tag:theconversation.com,2011:/us/topics/nerve-pain-27578/articlesNerve pain – The Conversation2018-11-25T19:06:01Ztag:theconversation.com,2011:article/1061632018-11-25T19:06:01Z2018-11-25T19:06:01ZAmbulance call-outs for pregabalin have spiked – here’s why<figure><img src="https://images.theconversation.com/files/246806/original/file-20181122-182071-2lpqex.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">At higher-than-prescribed doses, pregabalin causes sedation and euphoria.</span> <span class="attribution"><a class="source" href="https://unsplash.com/photos/i4rOpdj444c">Bruno van der Kraan</a></span></figcaption></figure><p>Pregabalin (sold under the brand name Lyrica) is prescribed as an anti-epileptic and a painkiller for nerve pain. Australian prescriptions of pregabalin have risen significantly in the past five years. It’s now in the <a href="https://www.nps.org.au/australian-prescriber/articles/top-10-drugs-2015-16">top ten most expensive medications for the Pharmaceutical Benefits Scheme</a> (PBS). </p>
<p>We’ve also seen a rise in “off-label” prescription of pregabalin. This means it’s being prescribed for conditions for which there is limited evidence of effectiveness. Pregabalin is <a href="https://www.nejm.org/doi/full/10.1056/NEJMp1704633">often prescribed</a> for chronic or persisting pain, for example, even when there is no clear nerve-related cause. </p>
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<a href="https://theconversation.com/explainer-why-are-off-label-medicines-prescribed-44783">Explainer: why are off-label medicines prescribed?</a>
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<p>Pregabalin is thought to have effects in the brain similar to those of benzodiazepines such as diazepam (Valium) by indirectly increasing levels of the neurotransmitter GABA. </p>
<p>Until recently, researchers and doctors <a href="https://europepmc.org/abstract/med/24849194">did not think pregabalin was addictive</a>. But now studies suggest pregabalin may also have an indirect effect on the brain’s reward chemical, dopamine. </p>
<p>Our research, published today in the <a href="https://www.mja.com.au/">Medical Journal of Australia</a>, shows ambulance call-outs associated with the misuse of pregabalin have increased tenfold in Victoria since 2012. This mirrors an increase in prescription rates.</p>
<h2>Growing evidence of misuse</h2>
<p>In 2010, the <a href="https://link.springer.com/article/10.1007/s00228-010-0853-y">first study</a> was published that reported on a trend of pregabalin misuse. </p>
<p>Since then, several <a href="https://link.springer.com/article/10.1007/s40263-014-0164-4">international research articles</a> have documented misuse, including <a href="https://link.springer.com/article/10.1007/s40265-017-0700-x">using higher doses than are recommended</a>. At higher-than-prescribed doses, pregabalin causes sedation and euphoria.</p>
<p>People who use opioids – painkillers like oxycodone, or illicit opioids such as heroin – have a particularly <a href="https://link.springer.com/article/10.1007/s40263-014-0164-4">high risk</a> of misusing pregabalin. So do those with a history of substance use problems. </p>
<p>People who use illicit drugs report often using pregabalin in combination with other drugs. Pregabalin <a href="https://link.springer.com/article/10.1007/s40263-014-0164-4">has been implicated</a> in drug-related deaths in individuals who weren’t prescribed the medication, and often in combination with other sedative medications or illicit drugs. </p>
<p>High rates of pregabalin use are also reported in secure environments, such as prisons, in both <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4657313/pdf/austprescr-38-160.pdf">Australia</a> and <a href="https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/385791/PHE-NHS_England_pregabalin_and_gabapentin_advice_Dec_2014.pdf">the United Kingdom</a>. </p>
<h2>What did we find?</h2>
<p>We analysed a unique database (<a href="https://www.turningpoint.org.au/research/population-health">the Ambo Project</a>) that documents all ambulance attendances related to alcohol and drug use and mental health in Victoria. </p>
<p>We found pregabalin-related ambulance attendances increased tenfold between 2012 and 2017, from 0.28 cases per 100,000 population to 3.32 cases per 100,000. Pregabalin misuse contributed significantly to 1,201 call-outs from 2012 to 2017. </p>
<p>Pregabalin has a sedative effect, which can be compounded when used with other drugs that cause sedation, including alcohol, or other prescribed medications such as benzodiazepines and sleeping tablets (such as Valium). </p>
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Read more:
<a href="https://theconversation.com/despite-escalating-prescriptions-nerve-pain-drug-offers-no-relief-for-sciatica-74699">Despite escalating prescriptions, nerve pain drug offers no relief for sciatica</a>
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<p>More than two-thirds of pregabalin-related ambulance call-outs were for people who also used other sedatives. Almost 90% required transport to hospital. In some situations, such sedation could be life-threatening.</p>
<p>Our findings of rising harms, especially from co-use with other drugs, echo findings from a <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/add.14412">New South Wales</a> research group that used data from poisons hotline calls, hospital admissions, and coronial reports from drug-related deaths. </p>
<h2>How to reduce the harms</h2>
<p>Doctors need to ensure patients are provided with the opportunity for careful and considered informed consent.</p>
<p>Pregabalin is a high-risk medication, especially when used with other sedatives. Although some doctors are aware of the side effects and harms associated with pregabalin, many are not. </p>
<p>The <a href="https://www.racgp.org.au/yourracgp/faculties/queensland/newsletter/september-2018/">Royal College of General Practitioners recently warned doctors</a> to carefully assess the risks when prescribing these medications, particularly for people who are also prescribed opioids or benzodiazepines. <a href="https://www.nps.org.au/news/gabapentinoid-misuse-an-emerging-problem">NPS MedicineWise</a> also recently highlighted the need for prescribers to exercise caution.</p>
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Read more:
<a href="https://theconversation.com/health-check-why-can-you-feel-groggy-days-after-an-operation-74989">Health Check: why can you feel groggy days after an operation?</a>
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<p>Better regulation is also needed. </p>
<p>Some Australian states including Victoria plan to implement <a href="https://www2.health.vic.gov.au/public-health/drugs-and-poisons/safescript">real-time prescription monitoring (RTPM)</a>. This would allow authorities to monitor and regulate access to high-risk medications such as opioid painkillers (oxycodone or similar) or benzodiazepines. </p>
<p>But pregabalin is not on the list of medications that will be captured by real-time prescription monitoring. To reduce the high risk of harm from pregabalin misuse, we should consider adding this drug to the list.</p>
<p>In the United Kingdom, pregabalin will become a “scheduled” or <a href="https://www.bmj.com/content/363/bmj.k4364">controlled medication</a> from April 2019. This means doctors will need to apply for a permit before prescribing it. </p>
<p>If this is found to be successful, Australia should consider following suit.</p><img src="https://counter.theconversation.com/content/106163/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>We would like to acknowledge the contribution of our co-authors Karen Smith, Debbie Scott and Paul Dietze. Thanks to Ambulance Victoria for providing the data and the Population Health team at Turning Point who code it to create this unique data set.
Shalini Arunogiri has previously received a scholarship from the National Health and Medical Research Council (NHMRC), and the Society for Mental Health Research (SMHR).
</span></em></p><p class="fine-print"><em><span>Dan Lubman has received funding from the National Health and Medical Research Council, the Australian Research Council, beyondblue, Movember, Victorian Department of Health and Human Services, Commonwealth Department of Health, Victorian Gambling Research Foundation and the Victorian Health Promotion Foundation. He has also received speaking honoraria from AstraZeneca, Indivior, Janssen, Servier, Shire and Lundbeck and has provided consultancy advice to Lundbeck and Indivior. </span></em></p><p class="fine-print"><em><span>Rose Crossin has previously received an RTP scholarship from the Australian Department of Education and Training. </span></em></p>Ambulance call-outs associated with the misuse of pregabalin (Lyrica) have increased tenfold in Victoria since 2012, mirroring an increase in prescription rates.Shalini Arunogiri, Addiction Psychiatrist, Lecturer, Monash UniversityDan Lubman, Director, Turning Point Alcohol and Drug Centre & Professor of Addiction Studies, Monash UniversityRose Crossin, Research Officer in Addiction Studies , Monash UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/746992017-03-23T02:06:23Z2017-03-23T02:06:23ZDespite escalating prescriptions, nerve pain drug offers no relief for sciatica<figure><img src="https://images.theconversation.com/files/161941/original/image-20170322-24884-mcaaom.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Your best option for treating the pain of sciatica is to seek advice, remain physically active, and wait it out. </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/423021505?src=ygXWUgqd6KdR4Gbs_As8dw-1-1&size=huge_jpg">from www.shutterstock.com </a></span></figcaption></figure><p><a href="http://www.nejm.org/doi/full/10.1056/NEJMra1410151">Sciatica</a> is a disabling condition characterised by pain in the leg along the distribution of the sciatic nerve. It can be accompanied by back pain, tingling, numbness, reduced strength and reflex changes in the leg. </p>
<p>Sciatica is most commonly caused by irritation of the nerve roots emerging from the lower spine. For this reason it is often considered a type of nerve pain. </p>
<p>It is estimated that around <a href="https://www.lumc.nl/sub/5038/att/812180307081046/905080238511046.pdf">5 to 10% of people with low back pain have sciatica</a>, equating to around 200,000 to 400,000 <a href="http://www.aihw.gov.au/back-problems/">Australians</a>. It is notoriously difficult to treat sciatica with over-the-counter medications and complementary therapies. </p>
<p>Our <a href="http://www.nejm.org/doi/full/10.1056/NEJMoa1614292?query=featured_home">study</a> released today examines the commonly prescribed nerve pain treatment pregabalin for acute and chronic sciatica. The results show that pregabalin does not improve pain symptoms or function, but is associated with unwanted side effects such as dizziness when compared to a placebo.</p>
<h2>Huge uptake of new drug</h2>
<p><a href="http://www.thelancet.com/journals/laneur/article/PIIS1474-4422(14)70251-0/abstract">Medicines</a> that have shown to be effective for treating nerve pain were considered to be an exciting new treatment option for sciatica.</p>
<p>These include drugs used to treat epilepsy, such as <a href="http://www.nps.org.au/publications/health-professional/health-news-evidence/2014/treating-neuropathic-pain">gabapentin and pregabalin</a>. These medicines, sometimes called gabapentinoids, seem to work by <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4804325/">preventing normal conduction</a> of pain signals along a nerve. </p>
<p><a href="https://theconversation.com/weekly-dose-lyrica-the-epilepsy-drug-that-treats-chronic-nerve-pain-56130">Pregabalin</a> became subsidised by the Australian government for nerve pain in 2013 and quickly became widely prescribed for conditions such as sciatica. In its first year of <a href="http://www.pbs.gov.au/info/industry/listing/participants/public-release-docs/pregabalin-24month-analysis-dusc-prd-10-2015-abstract">listing</a>, nearly 1.4 million prescriptions were written and in its second year, this figure increased to 2.4 million. This was 32% more than the government predicted. </p>
<p>Since its first approval in 2004 pregabalin has become the most widely prescribed medicine for nerve pain globally, with worldwide sales of between <a href="https://igeahub.com/2016/04/30/top-25-pharmaceutical-products-in-2015/">US$3-5 billion annually</a>. The astonishing growth is likely to be a consequence of many factors but may partly be a reflection of the lack of effective treatments for sciatica. </p>
<p>But while <a href="https://www.nps.org.au/radar/articles/pregabalin-lyrica-for-neuropathic-pain">pregabalin</a> has been shown to be effective for other types of nerve pain, there was <a href="http://www.thelancet.com/journals/laneur/article/PIIS1474-4422(14)70251-0/abstract">little evidence</a> it helped patients with sciatica. There were also emerging concerns of increased harmful effects, including risk of <a href="http://www.nejm.org/doi/full/10.1056/NEJMoa0909801#t=article">suicidality</a> and <a href="https://link.springer.com/article/10.1007%2Fs40263-016-0359-y">misuse</a>. </p>
<p>We designed our <a href="http://www.nejm.org/doi/full/10.1056/NEJMoa1614292?query=featured_home">study</a> to examine whether pregabalin is effective and has tolerable side effects in patients with sciatica.</p>
<h2>Pregabalin does not work for sciatica</h2>
<p>The <a href="http://www.nejm.org/doi/full/10.1056/NEJMoa1614292?query=featured_home">research</a> compared the effects of pregabalin against placebo (identical inactive capsules) in 207 patients with sciatica. </p>
<p>Patients were randomly assigned to take up to eight weeks of pregabalin or placebo, prescribed and monitored by a general practitioner or a medical specialist. To keep the results as unbiased as possible, patients, doctors and study staff were kept blinded to who was treated with pregabalin and who received placebo capsules. </p>
<p>This study found after eight weeks there was no difference in the severity of leg pain between those who took pregabalin and those who took placebo capsules. The same result was seen at one year. There were also no differences in other relevant outcomes, such as back pain severity and function, at either eight weeks or one year. </p>
<p>However, people who took pregabalin reported more adverse effects. The most common adverse effect reported in the trial was dizziness. </p>
<p>The study shows that taking pregabalin does not improve your sciatic symptoms when compared with placebo, but you are more likely to have adverse effects when taking pregabalin. </p>
<h2>Treatment options for sciatica</h2>
<p>Few alternative treatment options exist for people suffering from sciatica. </p>
<p>There is limited data describing the effects of <a href="http://annals.org/aim/article/2603230/nonpharmacologic-therapies-low-back-pain-systematic-review-american-college-physicians">nonsurgical treatments</a> such as exercise, spinal manipulation or acupuncture on sciatica. </p>
<p>There is also no convincing evidence to show <a href="http://annals.org/aim/article/2603229/systemic-pharmacologic-therapies-low-back-pain-systematic-review-american-college">medicines</a> such as anti-inflammatory drugs, oral corticosteroids or opioid analgesic medicines are effective. <a href="http://annals.org/aim/article/2430207/epidural-corticosteroid-injections-radiculopathy-spinal-stenosis-systematic-review-meta-analysis">Epidural corticosteroid injections</a> have been shown to have a small benefit in the short-term only. </p>
<p><a href="http://www.nejm.org/doi/full/10.1056/NEJMoa064039#t=article">Surgery</a> confers a short-term effect in selected patients with sciatica, but after a year people with sciatica who have not had surgery do just as well as people who’ve had the procedure.</p>
<p>The good news is that sciatica does get better with time. It’s important to stay as active as possible and to avoid prolonged bed rest (as this can delay recovery). </p>
<p>If you’re currently taking pregabalin, speak to a doctor about your condition, and mention any improvement or adverse effects you’ve experienced since starting pregabalin. It’s important not to stop pregabalin abruptly – usually doses should be reduced slowly over a few weeks. Abruptly stopping pregabalin can <a href="https://www.nps.org.au/radar/articles/pregabalin-lyrica-for-neuropathic-pain">have some ill effects</a> and should be done with care, close monitoring and advice from a doctor.</p>
<p>It’s unfortunate, but we do not currently have a lot of effective treatment options for people with sciatica. Speak to your doctor or treating clinician (such as a physiotherapist) about what may be appropriate for you, including specific advice on how you can stay as active as possible.</p><img src="https://counter.theconversation.com/content/74699/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Christine Lin receives a fellowship from the National Health and Medical Research Council of Australia (NHMRC). The PRECISE Study was funded by a grant from NHMRC, and Pfizer Australia provided the study active and placebo capsules free of charge. Investigators of the PRECISE study maintained full autonomy on the study design, conduct and report.</span></em></p><p class="fine-print"><em><span>Andrew McLachlan receives funding as the Program Director of the National Health and Medical Research Council of Australia (NHMRC) Centre for Research Excellence in Medicines and Ageing. The PRECISE Study on pregabalin in sciatica was funded by a project grant from NHMRC, and Pfizer Australia provided the study active and placebo capsules free of charge. Investigators of the PRECISE study maintained full autonomy on the study design, conduct and report. Andrew McLachlan has served as an external consultant related to regulatory submissions for Pfizer and Hospira. </span></em></p>Prescriptions of the drug pregabalin to treat sciatica have skyrocketed in recent years. But a new study shows it brings only side effects, and not relief for sufferers.Christine Lin, Senior Research Fellow, George Institute for Global HealthAndrew McLachlan, Professor of Pharmacy (Aged Care), University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/657372016-10-02T19:36:20Z2016-10-02T19:36:20ZStigma and empty wallets make HIV positive people carry on despite pain<figure><img src="https://images.theconversation.com/files/139727/original/image-20160929-27030-3ecwqw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">shutterstock</span></span></figcaption></figure><p><em>Up to three quarters of people living with HIV <a href="https://www.ncbi.nlm.nih.gov/pubmed/24560338">suffer from pain</a>. The Conversation Africa spoke to Antonia Wadley about research that measured activity and resilience among people living with HIV and pain.</em></p>
<p><strong>How is HIV-related pain different from other types of chronic pain?</strong> </p>
<p>People living with HIV experience pain similar to people with other chronic conditions. For example, people with HIV can have similar nerve pain in the feet and legs as diabetics. The significance of <a href="https://peerj.com/articles/2464.pdf">our study</a> is that HIV-positive patients react to their pain differently. </p>
<p>Many people with moderate to severe chronic pain find it difficult to move around. But we found that, in contrast, HIV-positive people who had chronic pain were still active.</p>
<p>There were two parts to our study: we measured activity and resilience (or a person’s ability to cope with adversity). We wanted to see if HIV-positive people with pain moved less than those without pain and if resilience affected how much they moved. We also wanted to know if resilience affected how much pain they felt. </p>
<p>We measured activity by getting participants to wear movement detectors over two weeks. It helped us understand how much patients with chronic pain moved and how much time they spent being active each day. The overarching finding was that activity levels did not drop as pain increased. </p>
<p>In <a href="http://rheumatology.oxfordjournals.org/content/52/9/1721.long">previous studies</a>, women who suffered from rheumatoid arthritis spent large parts of each day not moving. And similarly, women who experienced really bad period pain moved much less when they were <a href="https://www.ncbi.nlm.nih.gov/pubmed/18722817">menstruating</a>. </p>
<p>But people living with HIV and chronic pain did not stop their usual activities, despite the pain they experienced. </p>
<p>To measure resilience we used a questionnaire developed by <a href="https://www.ncbi.nlm.nih.gov/pubmed/7850498">pain researchers in the US</a>. Researchers from Europe have used this questionnaire to assess resilience in patients experiencing chronic spinal pain. They <a href="https://www.ncbi.nlm.nih.gov/pubmed/?term=ramirez-maestre%2C+2015%2C+resilience">found</a> that people who were more resilient coped better with chronic pain and were more active.</p>
<p>Our assumption was that the more resilient patients were, the more active they would be. This assumption proved to be incorrect. Resilience made no difference to activity levels. We also assumed that resilience would lead to participants experiencing less pain. But that wasn’t the case either. Patients who were more resilient did not have less pain. </p>
<p><strong>What type of pain do people living with HIV experience? How common is it?</strong></p>
<p>One in every two people with HIV experience pain. This includes headaches, chest pain, back pain or frequently peripheral nerve pain in their feet and hands. </p>
<p>The pain can be moderate to severe and can be caused by the immune system’s response to the virus or can co-occur with it. The pain does not tend to go away when patients go onto antiretroviral drugs. Some drugs have been shown to inadvertently <a href="http://www.jiasociety.org/index.php/jias/article/view/18719/3511">induce pain</a>. While the pain can be short-lived, it can also become chronic. </p>
<p><strong>So what factors did play a role in activity levels and why?</strong></p>
<p>There were two reasons why HIV-positive people with pain may have continued to be active: financial stresses and stigma. </p>
<p>We found that younger participants, unemployed participants and those who worried most about getting food were the ones who were more active. It seems they relegated their pain to a lower priority. </p>
<p>Our study also showed that stigma often stopped people from talking about their pain and may have motivated them to keep active. </p>
<p>We asked the participants with pain who they spoke to about their pain. Nearly half of the patients had not told their closest friends and some had not disclosed this to their family. They said they feared that talking about their pain might reveal their HIV status. </p>
<p><strong>Why are these findings important and what’s next?</strong></p>
<p>The HIV-positive patients who were more resilient were more satisfied with their health. </p>
<p>HIV-related pain is really difficult to treat. Improving resilience, for example with psychological treatments, may be one way of improving patients’ satisfaction with their health even if their pain stays the same. </p>
<p>With other kinds of chronic pain, people who keep active do better. But sometimes, pushing through pain can actually make pain intensity and disability worse. In this study we looked at how pain affects activity in HIV. Now we need to look at how activity affects pain. </p>
<p>We know that for patients with other kinds of pain, social support is really important to help them cope. HIV-positive patients may go without social support if they conceal their pain. We need to understand how they cope instead. </p>
<p>The impact of HIV stigma on pain also needs to be investigated.</p><img src="https://counter.theconversation.com/content/65737/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Antonia Wadley received funding from the Medical Faculty Research Endowment Fund of the University of the Witwatersrand and the Medical Research Council of South Africa.
</span></em></p>Many people with moderate to severe chronic pain find it difficult to move around. By contrast, HIV-positive people who had chronic pain are still active.Antonia Wadley, Lecturer in the School of Physiology, Faculty of Health Sciences, University of the WitwatersrandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/579432016-06-03T00:50:51Z2016-06-03T00:50:51ZWhat is chronic pain and why is it hard to treat?<figure><img src="https://images.theconversation.com/files/124195/original/image-20160526-22080-1hnaidv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">It hurts.</span> <span class="attribution"><a class="source" href="http://www.shutterstock.com/pic-392626384.html?src=download_history">Back pain image via www.shutterstock.com.</a></span></figcaption></figure><p>A recent study by the <a href="http://dx.doi.org/10.1016/j.jpain.2015.05.002">National Institutes of Health</a> found that more than one in three people in the United States have experienced pain of some sort in the previous three months. Of these, approximately 50 million suffer from chronic or severe pain. </p>
<p>To put these numbers in perspective, <a href="http://www.diabetes.org/diabetes-basics/statistics/">21 million people have been diagnosed with diabetes</a>, <a href="http://www.cancer.org/cancer/cancerbasics/cancer-prevalence">14 million have cancer</a> (this is all types of cancer combined) and <a href="http://www.cdc.gov/nchs/fastats/heart-disease.htm">28 million have been diagnosed with heart disease</a> in the U.S. In this light, the number of pain sufferers is stunning and indicates that it is a major epidemic. </p>
<p>But unlike treatments for diabetes, cancer and heart disease, therapies for pain have not really improved for hundreds of years. Our main therapies are non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen or aspirin, which are just modern versions of chewing on willow bark; and opioids, which are derivatives of opium. </p>
<p>In 2012 <a href="http://www.cdc.gov/mmwr/volumes/65/rr/rr6501e1.htm">259 million prescriptions for opioids</a> were filled in the United States. It is not clear how many of these prescriptions were for chronic pain. And indeed, <a href="http://www.cdc.gov/drugoverdose/pdf/guidelines_factsheet-a.pdf">new CDC guidelines</a> on the use of opioids to treat noncancer chronic pain caution physicians to consider the risks and benefits of using opioids when prescribing them to patients. </p>
<p>The fact is, however, that opioids are used to treat chronic pain not because they are the ideal treatment, but because for some patients, despite their drawbacks, they are the most effective treatment available at the moment. </p>
<p>The problem, as I see it, is this: we are not investing enough in researching and teaching what causes pain and how to treat it.</p>
<h2>Pain can have a purpose</h2>
<p>I study the processes that trigger and maintain chronic pain. One of the first things I teach my students is that pain is a biological process that is critical for life. Pain protects our bodies from injury and by reminding us that tissue is damaged and needs to be protected it also aids in repairing the injuries we do acquire. </p>
<p>This is graphically illustrated by individuals who are congenitally incapable of <a href="https://ghr.nlm.nih.gov/condition/congenital-insensitivity-to-pain">feeling pain</a>. People with these conditions typically succumb to infections or organ failure at a young age due to multiple injuries that go unattended. Because they cannot feel pain, they never learn to avoid hazards, or how to protect still-healing injuries. </p>
<p>For the most part, physicians and scientists are not particularly concerned with pain from everyday bumps, bruises and cuts. This type of acute pain typically does not require treatment or can be treated with over-the-counter medication. It will resolve itself when the tissue heals. </p>
<p>What concerns those of us who treat and study pain, however, is chronic pain. This <a href="http://www.ninds.nih.gov/disorders/chronic_pain/chronic_pain.htm#What_is">type of pain</a> – that can last for weeks, months or even years – serves no useful purpose for survival and is actually detrimental to our health. </p>
<p>There isn’t one type of chronic pain. </p>
<p>In many cases chronic pain persists after an injury has healed. This happens relatively often with <a href="http://www.ncbi.nlm.nih.gov/pubmed/20104399">wounded veterans</a>, car accident victims and others who have suffered violent trauma.</p>
<p>Chronic pain from arthritis is telling the person about the damage in their body. In this respect it is similar to acute pain and, presumably, if the body healed the pain would subside. But, at the moment, there is no treatment or intervention to induce that healing so the pain becomes the most troubling aspect of the disease. </p>
<p>Chronic pain can also arise from conditions, like <a href="http://www.niams.nih.gov/health_info/fibromyalgia/">fibromyalgia</a>, which have an unknown cause. These conditions are often misdiagnosed and the pain they produce may be dismissed by health care professionals as psychological or as drug-seeking behavior. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/124196/original/image-20160526-22060-ctbt03.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/124196/original/image-20160526-22060-ctbt03.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=357&fit=crop&dpr=1 600w, https://images.theconversation.com/files/124196/original/image-20160526-22060-ctbt03.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=357&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/124196/original/image-20160526-22060-ctbt03.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=357&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/124196/original/image-20160526-22060-ctbt03.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=449&fit=crop&dpr=1 754w, https://images.theconversation.com/files/124196/original/image-20160526-22060-ctbt03.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=449&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/124196/original/image-20160526-22060-ctbt03.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=449&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">How does the brain process pain?</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/wellcomeimages/16765237052/in/photolist-rxudTf-khquvW-9RPWDj-pUMbMm-qAAbSS-rg1jHu-pJKfTp-bGTZ8M-pEurqE-pWSMJH-9RPW2G-khnPbt-p66rbs-khnEji-rxzDXr-9RPW61-bPTEPp-9RM2RZ-9RM3SB-bBzyC7-9RQtvj-bQuf4v-wsfgQn-9RQtwf-GgbgLV-v7xRxC-FR4PY3-wGqd6G-wsfgYZ-Gp9WmY-ushSEP-v7FzRk-us8483-us84gj-a86X4e-ws7WZj-vGhbnc-vKwyJC-vMHGfE-ws7XuN-vMSe2x-wKeCrV-v7xUe9-vKwyKE-wJ2fsf-ws7XEs-wGqd9s-wJJTG6-ws7X6w-EpAGfH">Wellcome Images</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<h2>How do we experience pain?</h2>
<p>The human pain experience can be divided into three dimensions: what pain researchers call the sensory-discriminative, the affective-motivational and the cognitive-evaluative. In acute pain there is a balance between each of these dimensions that allows us to accurately evaluate the pain and the threat it may pose to our survival. In chronic pain these dimensions are disrupted. </p>
<p>The sensory-discriminative dimension refers to the actual detection, location and intensity of the pain. This dimension is the result of a direct nerve pathway from the body to the spinal cord and up into the brain’s cortex. This is how we are aware of the location on our bodies of a potential injury and how much damage may be associated with the injury. </p>
<p>Knowing where it hurts is only part of experiencing pain. Is your injury life-threatening? Do you need to run away or fight back? This is where the affective-emotional dimension comes in. It arises from the pain circuitry interacting with the limbic system (the emotional centers of the brain). This adds an emotional flavor to the incoming pain signal and is part of the fight-or-flight response. This pathway evokes the anger or fear associated with the possibility of physical harm. It also provokes learning so that in the future we avoid the circumstances leading to the injury. </p>
<p>The third dimension, the cognitive-evaluative, is the conscious interpretation of the pain signal, combined with other sensory information. This dimension draws on the different aspects of pain processing allowing us to determine the location and potential severity of an injury and to come up with survival strategies based on all available information.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/124197/original/image-20160526-22068-19svmb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/124197/original/image-20160526-22068-19svmb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=371&fit=crop&dpr=1 600w, https://images.theconversation.com/files/124197/original/image-20160526-22068-19svmb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=371&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/124197/original/image-20160526-22068-19svmb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=371&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/124197/original/image-20160526-22068-19svmb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=467&fit=crop&dpr=1 754w, https://images.theconversation.com/files/124197/original/image-20160526-22068-19svmb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=467&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/124197/original/image-20160526-22068-19svmb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=467&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">When pain is the disease.</span>
<span class="attribution"><a class="source" href="http://www.shutterstock.com/pic-178383632/stock-photo-senior-hands-suffering-from-pain-and-rheumatism.html?src=tD6LkwLNTEMhMfUawwBxAw-1-55">Hands images via www.shutterstock.com.</a></span>
</figcaption>
</figure>
<h2>When it always hurts</h2>
<p>The pain sensory system is designed for survival. If a pain signal persists, the default programming is that the threat to survival remains an urgent concern. Thus, the goal of the pain system is to get you out of harm’s way by ramping up the intensity and unpleasantness of the pain signal. </p>
<p>To increase the urgency of the pain signal, the sensory-discriminative dimension of pain becomes less distinct, leading to a more diffuse, less localized, pain. This pathway also amplifies the pain signal by rewiring spinal cord circuits that carry the signal to the brain, making the pain feel more intense.</p>
<p>If there is a threat to survival, the increasing intensity and unpleasantness of pain serves a purpose. But if the pain signal persists from, let’s say, arthritis or an old injury, the increased intensity and unpleasantness is unwarranted. This is what we define as chronic pain. </p>
<p>In chronic pain, as compared to acute pain, the affective-motivational dimension becomes dominant, leading to psychological consequences. Thus suffering and depression are much worse for chronic pain patients than it would be for an individual with an equivalent acute injury. </p>
<p>The multifaceted nature of pain is why opioids are often the most effective agents for both moderate to severe acute and chronic pain. </p>
<p>Opioids act at all levels of the pain neural circuitry. They suppress incoming pain signals from the peripheral nerves in the body, but importantly for chronic pain patients, they also inhibit the amplification of the signals in the spinal cord and improve the emotional state of the patient. </p>
<p>Unfortunately, patients rapidly develop tolerance to opioids, which significantly reduces their effectiveness for chronic therapy. Because of this as well as their addictive nature, potential for abuse and overdose, and side effects such as constipation, opioids are less than ideal agents for treating chronic pain. It is critical that we find alternatives. But that’s easier said than done. </p>
<h2>Funding for pain research lags</h2>
<p>In 2015 the National Institutes of Health spent US$854 million on <a href="https://report.nih.gov/categorical_spending.aspx">pain research</a>, compared to more than $6 billion for cancer. It is no wonder that pain patients muddle through with what amounts to centuries-old therapies.</p>
<p>The competition for funding for pain researchers is intense. In fact, many of my friends and colleagues, all highly experienced midcareer scientists, are leaving research because they cannot sustain the funding necessary to make any significant progress in finding treatments for pain. I, myself, spend up to 30 hours per week preparing and writing research proposals for funding agencies. Yet, less than one in 10 of these proposals are funded. The dearth of funding is also discouraging young scientists from doing pain research. With tenure at major universities becoming more and more difficult to attain, they can little afford to spend all of their time writing research proposals that do not get funded. </p>
<p>In addition, many medical and dental programs in the United States devote as little as one hour in their curriculum to teaching <a href="http://www.ncbi.nlm.nih.gov/pubmed/21945594">pain mechanisms and pain management</a>. Thus, most of our health professionals are poorly prepared to diagnose and treat chronic pain, which contributes to both the under treatment of pain and the abuse of opioids. </p>
<p>Unrelieved pain contributes more to human suffering than any other disease. It is time to invest in research to find safe effective therapies and on training health care providers to appropriately diagnose and treat pain.</p><img src="https://counter.theconversation.com/content/57943/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Robert Caudle receives funding from the National Institutes of Health and the Facial Pain Foundation. He is also a partner in Velocity Laboratories, LLC. Velocity Laboratories, LLC is a contract research organization.</span></em></p>Unrelieved pain contributes more to human suffering than any other disease.Robert Caudle, Professor of Oral and Maxillofacial Surgery, Neuroscience Division, University of FloridaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/561302016-05-18T06:39:31Z2016-05-18T06:39:31ZWeekly dose: Lyrica, the epilepsy drug that treats chronic nerve pain<figure><img src="https://images.theconversation.com/files/123111/original/image-20160519-6180-fpnc2t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Neuropathic pain often doesn't respond to common painkillers such as ibuprofen or paracetamol.</span> <span class="attribution"><span class="source">from shutterstock.com</span></span></figcaption></figure><p>Lyrica is the brand name for a prescription medicine called <a href="http://www.nps.org.au/medicines/pain-relief/simple-pain-reliever-and-fever-medicines/pregabalin-simple-pain-reliever-and-fever-medicines/lyrica-capsules-simple-pain-reliever-and-fever-medicines">pregabalin</a>. Although it is an anticonvulsant, or an anti-epileptic drug, pregabalin is commonly prescribed to alleviate <a href="http://www.racgp.org.au/afp/2013/march/neuropathic-pain-update/">nerve or neuropathic pain</a> – a type of pain caused by damage to, or a disease affecting, nerves.</p>
<p>Neuropathic pain <a href="http://theconversation.com/why-different-painkillers-are-only-effective-for-certain-types-of-pain-41035">doesn’t normally respond to common painkillers</a> such as ibuprofen or paracetemol. This is because the mechanisms that cause neuropathic pain are different to the underlying causes of other pain.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/122948/original/image-20160518-9509-1epk0n5.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/122948/original/image-20160518-9509-1epk0n5.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/122948/original/image-20160518-9509-1epk0n5.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=886&fit=crop&dpr=1 600w, https://images.theconversation.com/files/122948/original/image-20160518-9509-1epk0n5.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=886&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/122948/original/image-20160518-9509-1epk0n5.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=886&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/122948/original/image-20160518-9509-1epk0n5.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1113&fit=crop&dpr=1 754w, https://images.theconversation.com/files/122948/original/image-20160518-9509-1epk0n5.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1113&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/122948/original/image-20160518-9509-1epk0n5.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1113&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption"></span>
<span class="attribution"><a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<h2>History</h2>
<p>Pregabalin is closely related to <a href="http://www.drugs.com/gabapentin.html">gabapentin</a>, a medication developed to treat <a href="http://www.epilepsyaustralia.net/epilepsy-explained/">partial seizures</a>. This is a type of epilepsy caused by a surge in nerve cell excitability in one area of the brain.</p>
<p>Because nerve pain and epilepsy are related by abnormal levels of nerve excitability, an American neurologist <a href="http://www.priory.com/anaes/neuropathic.htm">tested gabapentin on patients</a> in the mid-1990s and found it relieved their neuropathic pain. </p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/122932/original/image-20160518-9494-1h15eza.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/122932/original/image-20160518-9494-1h15eza.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=402&fit=crop&dpr=1 600w, https://images.theconversation.com/files/122932/original/image-20160518-9494-1h15eza.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=402&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/122932/original/image-20160518-9494-1h15eza.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=402&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/122932/original/image-20160518-9494-1h15eza.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=505&fit=crop&dpr=1 754w, https://images.theconversation.com/files/122932/original/image-20160518-9494-1h15eza.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=505&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/122932/original/image-20160518-9494-1h15eza.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=505&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Pregabalin was registered by the TGA in 2005.</span>
<span class="attribution"><a class="source" href="https://upload.wikimedia.org/wikipedia/commons/3/32/Lyrica.jpg">By Acdx (Own work) [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Subsequently, pregabalin was developed as an improved version of gabapentin. The amount of pregabalin absorbed into the bloodstream increases in a linear fashion; unlike gabapentin where as the dose goes up, the proportion absorbed into the bloodstream goes down. This makes the effects of pregabalin more predictable than those of gabapentin.</p>
<p>Both are <a href="http://www.cpmc.org/professionals/research/about/news/neuropathic-pain-treatment.html">recommended as first line treatments</a> for nerve pain by the International Association for the Study of Pain. Lyrica was <a href="http://www.centerwatch.com/drug-information/fda-approved-drugs/drug/900/lyrica-pregabalin">approved in 2004</a> in the United States for the treatment of partial seizures of epilepsy and some neuropathic pain. </p>
<p>In 2007, pregabalin was approved in the United States to treat <a href="https://theconversation.com/hidden-and-unexplained-feeling-the-pain-of-fibromyalgia-48319">fibromyalgia</a>, a chronic disorder characterised by pain and muscle tenderness throughout the body. In Australia, it was registered by the <a href="https://www.ebs.tga.gov.au/ebs/picmi/picmirepository.nsf/pdf?OpenAgent&id=CP-2010-PI-04219-3">Therapeutic Goods Administration</a> in 2005. </p>
<h2>How it works</h2>
<p>In neuropathic pain, damaged nerve fibres are hyper-excitable, which means sensations such as light pressure or touch, which are normally barely felt, are perceived as painful. </p>
<p>Pregabalin (and gabapentin) are thought to interact with specific proteins in nerve endings in the brain and spinal cord. This reduces entry of calcium ions into nerve terminals to dampen release of pain neurotransmitter molecules in the spinal cord and brain.</p>
<h2>How Lyrica is used for pain</h2>
<p>Nerve pain is <a href="http://theconversation.com/why-different-painkillers-are-only-effective-for-certain-types-of-pain-41035">more severe</a> than non-neuropathic pain. Patients with persistent nerve pain often describe it as intense burning or shooting sensations in their arms, hands, fingers, legs, feet or toes. Because it’s often poorly relieved by available medications, the pain is unrelenting and intrudes into all activities of daily living.</p>
<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/122954/original/image-20160518-9480-4vy7uz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/122954/original/image-20160518-9480-4vy7uz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/122954/original/image-20160518-9480-4vy7uz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/122954/original/image-20160518-9480-4vy7uz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/122954/original/image-20160518-9480-4vy7uz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/122954/original/image-20160518-9480-4vy7uz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/122954/original/image-20160518-9480-4vy7uz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">In neuropathic pain, damaged nerve fibres are hyper-excitable.</span>
<span class="attribution"><span class="source">from shutterstock.com</span></span>
</figcaption>
</figure>
<p>About 7% to 8% of adults <a href="http://iasp.files.cms-plus.com/AM/Images/GYAP/Epidemiology%20of%20Neuropathic%20Pain.pdf">have chronic pain</a> with neuropathic characteristics. These include: feeling pain from light pressure or touch, such as clothing; hypersensitivity to mildly painful events such as bumps or knocks; burning, tingling and pins and needles; and abnormal sensations, such as ants crawling under the skin when touched.</p>
<p>Some groups have a <a href="http://iasp.files.cms-plus.com/AM/Images/GYAP/Epidemiology%20of%20Neuropathic%20Pain.pdf">higher prevalence of neuropathic pain</a> than others, particularly those who suffer from conditions that cause damage to the nerves, such as those with diabetes or following a bout of shingles.</p>
<p>Neuropathic pain is also common after certain operations, such as a mastectomy and affects about 35% of people with HIV infection. About 20% of cancer patients with chronic pain will have pain with neuropathic characteristics either because a tumour is pinching one or more nerves or because of damage to nerves that results from the cancer treatment itself. </p>
<p>The <a href="http://www.nps.org.au/publications/health-professional/nps-radar/2013/april-2013/pregabalin">recommended pregabalin dose</a> to relieve nerve pain is 150 mg to 600 mg per day. The doctor will initially prescribe a relatively low dose that is typically 75 mg once or twice daily; and 25 mg once or twice daily for the elderly or children. This will gradually be increased over several months.</p>
<h2>How Lyrica is used for epilepsy</h2>
<p>In people with <a href="http://www.epilepsy.org.au/about-epilepsy/understanding-epilepsy/seizure-types-classification">partial seizures</a>, a doctor may prescribe pregabalin as an add-on treatment to other anti-epileptic medications. But it is <a href="http://www.epilepsy.com/medications/pregabalin">not the best add-on treatment</a> for everyone. </p>
<p>The doctor will gradually increase the dose, usually starting at 75 mg twice a day or 50 mg three times a day. The goal is to reach the dose that <a href="http://www.epilepsy.com/medications/pregabalin">gives the best control of partial seizures</a> without causing troublesome side-effects.</p>
<h2>What it costs</h2>
<p>Pregabalin capsules are marketed in strengths ranging from 25 mg to 300 mg. It’s listed on the <a href="http://www.pbs.gov.au/medicine/item/2355Y">Pharmaceutical Benefits Scheme</a> in Australia, which means you pay up to A$38.30 for a pack of 56 capsules or A$6.20 if you have a concession card. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/122928/original/image-20160518-9458-1sguask.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/122928/original/image-20160518-9458-1sguask.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=580&fit=crop&dpr=1 600w, https://images.theconversation.com/files/122928/original/image-20160518-9458-1sguask.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=580&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/122928/original/image-20160518-9458-1sguask.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=580&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/122928/original/image-20160518-9458-1sguask.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=729&fit=crop&dpr=1 754w, https://images.theconversation.com/files/122928/original/image-20160518-9458-1sguask.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=729&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/122928/original/image-20160518-9458-1sguask.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=729&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Less common side-effects of Lyrica include blurred vision, dry mouth, fatigue and weight gain.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/rubbertoe/4831777541/in/photolist-8mY88k-t3Sirh-sLveSN-t1LJeG-d7EozE-iq6UbX-3rEHUV-9imqcE-9imp6h-7eQSoE-9iifer-9iigmc-58j2gf-9imkZA-faxSty-9iidUF-7tJ8LY-9immuy-9immYq-9imj7m-9imkwA-7b6wsp-9imkKd-9immRs-9iieyX-9iii8F-9imkcu-9iik22-9immCu-9iidLk-9iieUk-9iii16-9iigGP-9iihqr-9iidSr-9iifXP-9imo37-9imoRC-9iieeg-9imkqS-9imk6Q-9iihKR-9imm75-9iifsD-9imogh-9imnzm-9imns5-9imoYw-9imnjS-9immdA">Rubbertoe (Robert Batina)/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
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<h2>How many people use it?</h2>
<p>When pregabalin was first listed on the Pharmaceutical Benefits Scheme in 2013 to treat neuropathic pain, the then <a href="http://www.australiandoctor.com.au/news/latest-news/high-number-of-pregabalin-scripts-spark-pbs-invest">health minister announced</a> it would help 270,000 Australians. However, between June 2015 and 2016, <a href="http://medicarestatistics.humanservices.gov.au/statistics/do.jsp?_PROGRAM=%2Fstatistics%2Fpbs_item_standard_report&itemlst=%2702355Y%27&ITEMCNT=1&LIST=2355Y&VAR=SERVICES&RPT_FMT=1&start_dt=201407&end_dt=201506">pregabalin’s item number</a> was claimed around 650,000 times. This may be because the effects of pregabalin are more predictable than those of its predecessor, gabapentin.</p>
<h2>Side-effects</h2>
<p>The main <a href="http://www.nps.org.au/publications/health-professional/nps-radar/2013/april-2013/pregabalin">side-effects of pregabalin</a> are drowsiness, dizziness, impaired balance and an inability to think properly. These are more likely to occur soon after treatment starts and may diminish with time. Less common side-effects include blurred vision, dry mouth, fatigue and weight gain.</p>
<p>Side-effects are the main reason patients stop taking pregabalin for nerve pain. So it is really important that the initial dose is not too high and that the dosage gets increased slowly, especially in older people and those with impaired kidney function.</p>
<h2>Special considerations</h2>
<p>Pregabalin is excreted from the body in urine through the kidneys. People with impaired kidney function <a href="http://www.nps.org.au/publications/health-professional/nps-radar/2013/april-2013/pregabalin">need lower doses of pregabalin</a> as the drug would be excreted more slowly. Pregabalin is not broken down in the liver so it does not interfere with the liver breakdown of other medications.</p>
<p>Prolonged use of pregabalin <a href="http://theconversation.com/why-different-painkillers-are-only-effective-for-certain-types-of-pain-41035">does not produce tolerance and dependence</a>, nor does it have the same potential for misuse, abuse or addiction. Pregabalin can also be used safely with other pain-killers such as paracetamol and morphine.</p><img src="https://counter.theconversation.com/content/56130/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Maree Smith currently holds competitive research grant funding from the Australian Research Council in collaboration with Boehringer Ingelheim GmbH, from the National Health and Medical Research Council as well as NCRIS 2015 funding from Therapeutic Innovation Australia (TIA Ltd) for the THMR project. Maree Smith is named inventor on patented AT2 receptor antagonist technology for the relief of neuropathic and chronic inflammatory pain, commercialized by the UQ spin-out company, Spinifex Pharmaceuticals (2005-2015), that was acquired by Novartis in mid-2015. Maree Smith conducts contract R&D studies in collaboration with multiple companies in her role as Director of the Centre for Integrated Preclinical Drug Development at The University of Queensland. She is currently President and Board member of the Australian Pain Relief Association (APRA) and she is a member of the Editorial Board of Pain: Clinical Updates.</span></em></p><p class="fine-print"><em><span>Brendan Moore acted in a paid advisory role for pharmaceutical companies, including Pfizer, more than five years ago. </span></em></p>Lyrica, the brand name for a medicine called pregabalin, is an anti-epileptic drug most commonly used to treat chronic nerve pain - a type of pain caused by abnormality in, or damage to, the nerves.Maree Smith, Director, Centre for Integrated Preclinical Drug Development and Professor of Pharmacy, The University of QueenslandBrendan Moore, Adjunct Associate Professor, The University of QueenslandLicensed as Creative Commons – attribution, no derivatives.