Studies Warn of Pregabalin Deaths

By Pat Anson, Editor

Two new studies – one in Canada and one in Australia – should give pause to patients who use opioids and pregabalin (Lyrica), an anticonvulsant medication increasingly prescribed for fibromyalgia, neuropathy and other chronic pain conditions. Both studies found a number of overdose deaths that involve – but were not necessarily caused -- by pregabalin.

The Canadian study, published in the Annals of Internal Medicine, looked at over 1,400 patients in Ontario on opioid medication from 1997 to 2016 who died from opioid-related causes. Another group of over 5,000 surviving opioid patients was used as a control group.

Researchers found that patients who were co-prescribed opioids and pregabalin had a significantly higher risk of an overdose.

The risk of death was over two times higher for patients receiving opioids and a high dose of pregabalin (over 300mg) compared to those who took opioids alone.

Patients on a low or moderate dose of pregabalin also had a heightened risk, although not as large.

Lyrica2.jpg

Researchers say pregabalin has a sedative effect and may interact with opioids in ways that increase respiratory depression. Few doctors and patients are aware of the risk, even though over half of Ontario residents who begin pregabalin therapy are also prescribed an opioid.

"There is an important drug interaction between opioids and pregabalin that can lead to increased risk of fatal overdose, particularly at high doses of pregabalin," lead author Tara Gomes, PhD, of the Institute for Clinical Evaluative Sciences (ICES) and St. Michael's Hospital in Toronto, told MedPage Today.

"Clinicians should consider carefully whether to prescribe opioids and pregabalin together. If they decide that both medications are clinically appropriate, they should start with low doses and monitor their patients closely."

Lyrica (pregabalin) and Neurontin (gabapentin) are both made by Pfizer and belong to a class of anticonvulsant nerve medication called gabapentinoids. Sales of gabapentinoids have tripled in recent years, in part because of CDC prescribing guidelines that recommend the drugs as alternatives to opioid medication.  

U.S. health officials have only recently started looking into the misuse and abuse of gabapentinoids, which are increasingly used by addicts to enhance the euphoric effects of heroin and other illicit opioids. While gabapentin  has a warning label cautioning users who take the drug with opioids, there is no similar warning for pregabalin.

“Although current product monographs for gabapentin contain warnings about serious adverse events when this agent is combined with opioids, those for pregabalin do not. The importance of our finding warrants a revision of the pregabalin product monographs,” wrote Gomes.

Pregabalin Abuse in Australia

Health officials in Australia are also concerned about the growing use of pregabalin.  Researchers at the NSW Poisons Information Centre say poisoning cases involving pregabalin rose from zero in 2005 to 376 cases in 2016.

“Our study shows a clear correlation between the rapid and continuous rise of pregabalin dispensing and an increase in intentional poisonings and deaths associated with pregabalin,” said lead author Dr. Rose Cairns, a specialist at the NSW Poisons Information Centre.

According to the Australian Journal of Pharmacy (AJP), there have been 88 recorded deaths associated with pregabalin in recent years. Most of the deaths involved young, unemployed males who had a history of substance abuse, particularly with opioids, benzodiazepines, alcohol and illicit drugs.

“We believe that Australian doctors may not be aware of the abuse potential of pregabalin,” Cairns said. “Most patients who are prescribed this medication are in the older population but the group who are at high risk of overdosing are much younger. These people are likely to have been prescribed pregabalin despite having a history of substance abuse.”

According to researchers, up to two-thirds of people who intentionally misused pregabalin had a prior documented substance abuse history. “Prescribers need to consider this growing body of evidence that pregabalin has abuse potential before prescribing, especially to patients with substance abuse history,” said Cairns.

Pfizer did not respond to a request for comment on the Canadian and Australian studies.

New Treatments on Horizon for Chronic Pain

By Steve Weakley

Patients and doctors have long complained that there are few new treatments for chronic pain. And those that do come along are often reformulations of old medications or have unwelcome side effects.

Two developments this week suggest that trend may be changing. A new drug application has been submitted to the Food and Drug Administration for an “opioid of the future” that is less addictive, and research has uncovered a new way to treat neuropathic pain long term with a single injection.

In experiments on laboratory mice, researchers at the University of California at San Diego discovered a new method to block the root cause of pain with the injection of a naturally occurring protein, apolipoprotein A-I binding protein (AIBP). 

AIBP “turns off” a receptor called TLR4 that sits on the surface of nerve cells and searches for signs of infection or tissue damage.  Researchers say turning off the receptor prevents and even reverses inflammation and other cellular processes that create the sensation of pain.

bigstock-Scientist-Or-Chemist-With-Petr-2935640.jpg

A single spinal injection of AIBP relieved neuropathic pain associated with chemotherapy in the mice for two months with no side effects, according to findings published in the journal Cell.

“What’s so special about our new approach, inhibiting the TLR4 receptor with AIBP, is that it actually modifies the pain processing systems themselves," says study co-author Tony Yaksh, PhD, a professor and vice chair for research in the Department of Anesthesiology at UCSD School of Medicine.

"So, if you think of neuropathic pain as a disease, then we see this as truly disease-modifying. We’re blocking the underlying mechanism that causes pain, not just masking the symptoms.”

Neuropathic pain is a common side effect of chemotherapy treatments for cancer. Chemotherapy not only inhibits the growth of cancer cells, it can permanently damage nerve cells and make people sensitive to even the slightest touch. Opioids and other medications such as gabapentin (Neurontin) are commonly prescribed for neuropathy, but both have unwelcome side effects.

“If it comes down to a choice between living with chronic pain or getting a spinal injection once every few months, we think most people would take the injection," said co-author Yury Miller, MD, a professor in the UCSD Department of Medicine. “As it stands now, AIBP could be developed as therapy for unremitting severe pain that only responds to high dose morphine. AIBP would remove the need for opioids, and reduce the potential for drug abuse.

"We're not saying we shouldn't use opiates to treat chronic pain, or in particular cancer pain—that would be a tragedy.” Yaksh said. "But it would also be a greater tragedy if we didn't support work to find a substitute for systemic opiates.”

“Opioid of the Future”

While AIBP is still in its experimental phase and could be years away from being available for treatment, Nektar Therapeutics’ so-called “opioid of the future” is one step closer to market.  Nektar has completed over a dozen clinical trials on NKTR-181 and applied to the FDA for approval of the drug as a treatment for chronic low back pain.

PNN has previously reported on NKTR-181, a new type of opioid that shows promise in relieving moderate to severe pain with less risk of abuse and addiction of traditional opioids like oxycodone or hydrocodone.

Because of its slow rate of entry into the central nervous system, NKTR-181 significantly reduces the “high” or euphoric effect that recreational drug users crave. Many pain sufferers don't feel that high when taking opioid medication, they just get pain relief.

In trials, NKTR-181 showed a 65% reduction in low back pain vs. placebo in tablets taken twice a day. Safety studies found recreational drug users had significantly less “drug liking” of NKTR-181 -- even at high doses -- when compared to oxycodone. Participants also had less daytime sleepiness and fewer withdrawal symptoms.

 nektar therapeutics

nektar therapeutics

If it receives FDA approval, Nektar hopes to launch the drug commercially as early as next year. The company has yet to announce a partnership with a larger pharmaceutical company to help produce and commercialize NKTR-181 -- which is when the no-name "opioid of the future" will get a makeover with a branded name to make it more marketable.

Growing Abuse of Gabapentin

By Christine Vestal, Stateline

Doctors who are cutting back on prescribing opioids increasingly are opting for gabapentin, a safer, non-narcotic drug recommended by the Centers for Disease Control and Prevention.

By doing so, they may be putting their opioid-using patients at even greater risk.

Recently, gabapentin has started showing up in a substantial number of overdose deaths in hard-hit Appalachian states. The neuropathic (nerve-related) pain reliever was involved in more than a third of Kentucky overdose deaths last year.

Drug users say gabapentin pills, known as “johnnies” or “gabbies,” which often sell for less than a dollar each, enhance the euphoric effects of heroin and when taken alone in high doses can produce a marijuana-like high.

Medical researchers stress that more study is needed to determine the role gabapentin may have played in recent overdose deaths. However, a study of heroin users in England and Wales published last fall concluded that combining opioids and gabapentin “potentially increases the risk of acute overdose death” by hampering breathing and reversing users’ tolerance to heroin and other powerful opioids.

neurontin-cap-300mg-neurontin-cap-300mg-neurontin-min-min.jpg

Kentucky last year classified gabapentin as a controlled substance, making it harder for doctors to prescribe it in copious quantities and for long durations. The new classification also allows police to arrest anyone who illicitly sells the drug, although the state’s drug control chief, Van Ingram, said that was not the intent of the new law.

In the last two years, Illinois, Ohio, Massachusetts, Minnesota, Tennessee, Virginia and Wyoming also have moved to control the flow of gabapentin by requiring doctors and pharmacists to check a prescription drug database before prescribing it to patients to make sure they aren’t already receiving gabapentin, or some other medication that interacts with it, from another physician.

In a statement to Stateline, Pfizer communications director Steven Danehy said, “Reports of misuse and abuse with this class of medicines are limited and typically involve patients with a prior history of substance abuse, including opioids.”

The drugmaker also pledged to “continue working with regulatory authorities and health officials to evaluate and monitor the safety of these medicines.”

Prescribed for Many Conditions

Approved by the FDA in 1993 for the treatment of epilepsy and the nerve pain associated with shingles, gabapentin is sold by Pfizer under the brand name Neurontin. A generic form of the drug has been available since 2004 and is now sold by several other companies as well.

Gabapentin is now one of the most popular prescription drugs in the United States, according to the New England Journal of Medicine. It was the 10th-most-prescribed medication in 2016. Its more expensive cousin, pregabalin, sold as Lyrica and also made by Pfizer, was the eighth best-selling.

Many doctors recommend gabapentin to patients for a long list of disorders, including hot flashes, migraines, restless leg syndrome, fibromyalgia, and neuropathic pain associated with diabetes and spinal injuries. Some doctors also prescribe it for anxiety and insomnia.

Now, research is underway to determine whether gabapentin may be effective as a treatment for alcoholism.

Already, it is widely used to ease the symptoms of drug and alcohol detoxification. And addiction specialists routinely use gabapentin to manage pain in people who are either addicted or at risk of addiction to opioids and other substances.

Alone, high doses of gabapentin have not been found to affect breathing. The vast majority of gabapentin deaths, about 4 in 5, also involved opioids, according to the journal Addiction.

People who stop taking the medication abruptly, however, can suffer withdrawal symptoms such as trembling, sweats and agitation.

In February, Food and Drug Administration director Scott Gottlieb said the agency was reviewing the misuse of gabapentin and, for now, had determined no action was necessary. Similarly, the CDC has not issued a warning about gabapentin, nor has the Drug Enforcement Administration.

(Editor's note: the CDC opioid guidelines recommend gabapentin without any mention of the risk of abuse or overdose associated with the drug, or of possible side effects such as weight gain, anxiety and mood disorders.)

Early Signs of Abuse

In Kentucky, Ingram said it has been clear to police and pharmacists for the last three or four years that gabapentin was becoming an increasingly popular street drug. “People were seeking early refills, claiming they lost their prescriptions and openly conducting transactions in parking lots outside of drug stores,” he said.

But since it wasn’t a controlled substance, nothing was done about it. That’s likely to start changing with the new law, he said.

“Misuse of gabapentin is just one more collateral effect of the opioid epidemic,” said Caleb Alexander, an epidemiologist at Johns Hopkins University who has been studying the heroin and prescription drug epidemic. When one drug becomes less available, drug users historically seek out alternatives, he said. “What is most surprising is the sheer magnitude of its use.”

The share of Appalachian drug users who reported using gabapentin to get high increased nearly 30-fold from 2008 to 2014, according to a 2015 study in the American Journal of Psychiatry.

Paul Earley, an addiction doctor practicing in Georgia and a board member of the American Society of Addiction Medicine, said, “We knew that a small subset of our addiction patients would abuse gabapentin.” But he said it wasn’t until 2016, when Ohio sounded an alarm about the drug’s association with overdose deaths, that addiction doctors started taking the problem more seriously.

“For years, we considered gabapentin to be ‘good for what ails you,’” Earley said. “But I’m much more cautious than I used to be. If there’s anything we’ve learned from the opioid epidemic, it’s that we need to rethink how we prescribe drugs we once assumed were safe.”

This is story is republished with permission by Stateline, an initiative of The Pew Charitable Trusts.

Light Therapy Used to Treat Neuropathic Pain

By Pat Anson, Editor

For someone with peripheral neuropathy, even the slightest touch can cause burning, stinging or shooting pain, usually in the hands or feet.

The pain is caused when the peripheral nervous system is damaged by diabetes, shingles, chemotherapy or some other medical condition. About 8% of adults worldwide suffer from some form of neuropathy. Medications prescribed to dull the pain – such as opioids, anti-depressants or gabapentin (Neurontin) -- often prove to be ineffective, don’t last long or have unwanted side effects.

Scientists in Italy have now discovered an experimental way to treat neuropathy that provides pain relief for weeks at a time without the use of medication. In experiments on laboratory mice, researchers at the European Molecular Biology Laboratory (EMBL) in Rome identified a specific set of nerve cells in mouse skin that play a significant role in neuropathic pain.

 NATURE COMMUNICATIONs

NATURE COMMUNICATIONs

When injected with a light-sensitive chemical and then exposed to infrared light, the nerve cells pull away from the skin’s surface and stop sending pain signals. The pain-relieving effects of the light therapy appear to last for weeks.

The accompanying image shows the skin of a mouse, with the nerve cells that are responsible for sensitivity to touch highlighted in green. The neurons are primarily located around hair follicles.

The EMBL's research, first reported in the journal Nature Communications, is still in its early stages. But scientists say human skin tissue is similar to that of mice, indicating that light therapy might be effective in managing neuropathic pain in humans.

"In the end, our aim is to solve the problem of pain in both humans and animals," says Paul Heppenstall, PhD, EMBL group leader. "Of course, a lot of work needs to be done before we can do a similar study in people with neuropathic pain. That's why we're now actively looking for partners and are open for new collaborations to develop this method further, with the hope of one day using it in the clinic."

Heppenstall says light therapy works on the treated nerve cells the same way spicy food or capsaicin patches can cause nerve fibers to retract.  

"It's like eating a strong curry, which burns the nerve endings in your mouth and desensitizes them for some time," says Heppenstall. "The nice thing about our technique is that we can specifically target the small subgroup of neurons causing neuropathic pain."

There are many different types of nerve cells in skin, which respond to different sensations like vibration, cold, heat or normal pain. Researchers say those cells are not affected by the light treatment. The skin is only desensitized to a gentle touch, breeze, or tickling.

Previous attempts to develop drugs to treat neuropathic pain have mostly focused on targeting single molecules.

"We think however, that there's not one single molecule responsible, there are many," Heppenstall explains. "You might be able to succeed in blocking one or a couple, but others would take over the same function eventually. With our new illumination method, we avoid this problem altogether."

The neuropathic pain in mice was assessed with a simple touch. The mice would normally quickly withdraw their paw when it was gently touched, but after light therapy they exhibited normal reflexive response to touch. The effect of the therapy lasted for a few weeks, until the nerve endings grew back and the gentle touch caused pain again.

Opioid Hysteria Has Gone Too Far

By Lisa Kehrberg, MD, Guest Columnist

I’m a 43-year-old physician who retired due to illness at the age of 39. I have a rare genetic disease called acute intermittent porphyria (AIP), an extremely painful and disabling condition.

Due to an enzyme deficiency, AIP causes toxins to buildup in the liver. The symptoms of porphyria are primarily neurological with the most notable being abdominal pain -- a burning sensation that is almost unbearable. The pain is similar to what I’d imagine it would feel like to have a blowtorch placed against my stomach and back.

Acute porphyria also causes peripheral neuropathy in the hands and feet. Along with the pain comes severe nausea, vomiting, headaches, fatigue, muscle weakness, motor neuropathy, and fluctuations in blood pressure and pulse. About 10 percent of AIP patients have a severe form of the disease referred to as “high excreter, recurrent attacks.”

Unfortunately, I am in that 10 percent.

Initially, I only had monthly attacks lasting 3-5 days, starting in my teenage years. Somehow, I managed to complete my education and training and became a physician despite that.

I was not finally diagnosed with AIP until the age of 39, when I suffered a life-threatening porphyria attack. It was almost too late for me at that point, as the attack was so severe that I was no longer able to work or do much at all. There is a one percent mortality rate during each AIP attack and I’ve had hundreds of them, so I’ve been lucky.

My older brother died unexpectedly at the age of 39. Genetic testing of autopsy samples later determined he had the same AIP gene mutation as I have. He died prior to my diagnosis and his gene mutation was discovered as I lay in a hospital bed being told my diagnosis.

 LISA KEHRBERG, MD

LISA KEHRBERG, MD

At first, I felt such strong relief that my life was saved and sadness for my brother. But as the months passed, and I became sicker and more in pain, I started feeling a bit jealous of my brother. He was able to at least die with some dignity and is no longer suffering.

The pain that I experience is severe and the only thing effective enough to bring it down to tolerable levels is opioid medication. I’ve tried everything possible. Pain is a subjective experience and only the person experiencing it can know the severity and what helps to improve it.

I have difficulty understanding the response from some in the medical community, government, media and general public, who are so focused on “opioid addiction” that they are unable to see patients like me and empathize with us.

The media’s response has been extremely damaging. It seems people do not understand that addiction is a separate issue from pain management. Why is it that every time prescription pain medication is discussed, it's only in reference to addiction and the opioid epidemic? What about people like me who live with a life-threatening and severely painful disease? Not many reporters seem interested in that side of the story.

I have watched now as countless pain patients have taken their own lives due to discontinuation of their pain medication, often without any warning or consent. Physicians are not the problem in this. Physicians want to help patients. Physicians are being misled, brainwashed and even punished into thinking that prescription opioids usually lead to addiction.

Fortunately for patients like me, palliative care is a growing field and I’m so appreciative of my palliative care physician. I’m frightened for the future, not only for myself, but really for everyone. Pain affects everybody at some point in their lives. Whether it’s you, a family member or a friend -- pain will be there.

Everybody should be afraid of the direction where things are going. Even cancer patients at end of life are being denied appropriate pain treatments. Insurance companies are denying coverage for pain medications and getting away with it. I encourage everyone to please use common sense in this climate where the pendulum has swung too far in the wrong direction.

bigstock-Tell-Us-Your-Story-card-with-c-78557009.jpg

Lisa Kehrberg, MD, is a retired family practice physician who specialized in pain management. You can read more about Lisa at the American Porphyria Foundation’s website.

Pain News Network invites other readers to share their stories with us. Send them to editor@painnewsnetwork.org.

The information in this column should not be considered as professional medical advice, diagnosis or treatment. It is for informational purposes only and represents the author’s opinions alone. It does not inherently express or reflect the views, opinions and/or positions of Pain News Network.

Gluten-Free Diet May Relieve Neuropathy Pain

By Pat Anson, Editor

A small study by British researchers suggests that a strict gluten-free diet may help protect against the nerve pain caused by gluten sensitivity.

"These findings are exciting because it might mean that a relatively simple change in diet could help alleviate painful symptoms tied to gluten neuropathy," said lead author Panagiotis Zis, MD, a senior lecturer at the University of Sheffield. "While our study shows an association between a self-reported gluten-free diet and less pain, it does not show that one causes the other."

Gluten sensitivity has been associated with peripheral neuropathy -- a condition in which peripheral nerves become damaged, causing weakness, numbness and pain in the hands and feet. Diabetic neuropathy can also cause these symptoms, but when diabetes is ruled out and a person is sensitive to gluten – the pain and numbness might be caused by gluten neuropathy.

bigstock-Gluten-free-symbol-22894205.jpg

The British study involved 60 mostly elderly people who had gluten neuropathy. They were asked about the intensity of their pain, mental health and whether they followed a strict gluten-free diet. About half of the participants had pain with their neuropathy.

People who were following a gluten-free diet were significantly more likely to be free of pain than those who did not. Over half of those without pain were on a gluten-free diet, while 21 percent who were gluten-free still experienced pain.

After adjusting for age, sex and mental health status, researchers found that people following the strict diet were 89 percent less likely to have pain.  

The study also found that people with painful gluten neuropathy scored significantly worse on their mental health assessment, which had a range of zero to 100 with 100 being best. Those with painful gluten neuropathy had an average score of 76, as opposed to the average score of 87 for those with painless gluten neuropathy.

"This study is promising because it shows that a gluten-free diet may help lower the risk of pain for people with gluten neuropathy," Zis said. "More research is needed to confirm these results and to determine whether the gluten-free diet led to the reduction in pain."

Further results of the study will be presented at the annual meeting of the American Academy of Neurology in April.

Gluten is a protein found in wheat, rye, barley, oats and other cereal grains. Gluten is found in many types of food, including bread, pasta, cereal, sauces and salad dressing.

When people with celiac disease eat gluten, it triggers an immune response that attacks the small intestine, causing pain and inflammation. About 1-2% of the population has celiac disease, but most cases go undiagnosed and untreated. Celiac disease is hereditary and runs in families.

People with non-celiac gluten sensitivity (NCGS) may also develop gastrointestinal symptoms, as well as headaches, chronic fatigue, fibromyalgia and allergies. Abdominal pain and irregular bowel movements are frequently reported with NCGS, which can make it difficult to distinguish from irritable bowel syndrome (IBS).

Research about the relationship between gluten and chronic pain conditions is rather slim, although there are many anecdotal reports that a gluten free diet reduces pain. In PNN columns, Donna Gregory Burch said going gluten-free helped reduce her fibromyalgia symptoms, while Lisa Ayres found that eliminating gluten quickly relieved her arthritis symptoms.  

Should Gabapentin Be a Controlled Substance?

By Pat Anson, Editor

The U.S. Drug Enforcement Administration should consider scheduling gabapentin (Neurontin) as a controlled substance, according to researchers who studied the recreational use of the drug in Kentucky.

Gabapentin is a nerve medication approved by the Food and Drug Administration to treat epilepsy and post-herpetic neuralgia (shingles), but it is also widely prescribed off-label to treat fibromyalgia, migraines, neuropathy and other chronic pain conditions. The Centers for Disease Control and Prevention even recommends gabapentin as a safer alternative to opioids.

Sales of gabapentin have soared in recent years. About 64 million prescriptions were written for gabapentin in the U.S. in 20l6, a 49% increase in just five years.

But drug abusers have also discovered that gabapentin can heighten the effects of heroin, marijuana, cocaine and other substances.

"People are looking for other drugs to substitute for opioids, and gabapentin has filled that place for some," said Rachel Vickers Smith, PhD, an assistant professor at the University of Louisville School of Nursing. “Some have said it gives them a high similar to opioids. It had been easy to get a prescription for gabapentin and it's very cheap."

gabapatin.jpg

Vickers Smith and her colleagues recruited 33 people from Appalachian Kentucky who used gabapentin recreationally and asked them about their drug use. Many reported they started taking gabapentin over 10 years earlier for a legitimate medical condition, such as pain and anxiety. Over time, they started using the drug to help them relax, sleep and get high.

“Focus group responses highlighted the low cost of gabapentin for the purpose of getting high and noted increasing popularity in the community, particularly over the last 2 years. Gabapentin was a prominent drug of abuse in two cohorts of the primarily opioid-using individuals. Providers should be aware of gabapentin’s abuse potential, and a reexamination of the need for scheduling is warranted,” researchers reported in the journal Psychology of Addictive Behaviors.

In 2017, Kentucky became the first state to classify gabapentin as a controlled substance, which makes it more difficult for the medication to be prescribed. Ohio’s Substance Abuse Monitoring Network also issued an alert warning of gabapentin misuse across the state.

‘Snake Oil of the 20th Century’

Gabapentin was first approved by the FDA in 1993 and sold by Pfizer under the brand name Neurontin. A few years later, it was so widely prescribed that a top Pfizer executive called gabapentin “the snake oil of the twentieth century” in an email. The company was later fined hundreds of millions of dollars for promoting Neurontin’s off-label use.

"Early on, it was assumed to have no abuse potential," says Vickers Smith. "There's a need to examine it in further detail, especially if prescribing it is going to be encouraged."

Federal health officials have only recently started looking into the misuse and abuse of gabapentinoids, a class of nerve medication that includes gabapentin and pregabalin (Lyrica).

"Our preliminary findings show that abuse of gabapentinoids doesn't yet appear to be widespread, but use continues to increase, especially for gabapentin," FDA commissioner Scott Gottlieb, MD, said last week at a conference on opioid prescribing. "We're concerned that abuse and misuse of these drugs may result in serious adverse events such as respiratory depression and death. We want to understand changes in how patients are using these medications."

Gottlieb said FDA investigators are looking at websites and social media where opioid users discuss their use of gabapentinoids.

"We know we need to investigate and respond to signs of abuse as soon as signals emerge. We need to get ahead of these problems," he said.

Gabapentin is not currently scheduled as a controlled substance by the DEA, while Lyrica is classified as a Schedule V controlled substance, meaning it has a low potential for addiction and abuse.  

Lyrica and Neurontin Use Triples

By Pat Anson, Editor

The use of gabapentin (Neurontin) and pregabalin (Lyrica) has soared in the United States, with little attention paid to their safety and effectiveness, according to a research letter published in JAMA Internal Medicine.

Gabapentin and pregabalin belong to a class of nerve medication known as gabapentinoids, which are increasingly prescribed as alternatives to opioids in treating neuropathy, fibromyalgia and other types of chronic pain.

In an analysis of health data for nearly 350,000 patients, researchers found that the use of gabapentinoids more than tripled in the past decade, from 1.2% of patients in 2002 to 3.9% in 2015.

Use of the drugs was concentrated in older patients with numerous other health problems, who were often co-prescribed opioids or benzodiazepines, a class of anti-anxiety medication.

bigstock-Pouring-capsules-from-a-pill-b-46714792.jpg

“The combination of a dearth of long-term safety data, small effect sizes, concern for increased risk of overdose in combination with opioid use, and high rates of off-label prescribing, which are associated with high rates of adverse effects, raises concern about the levels of gabapentinoid use,” wrote lead researcher Michael Johansen, MD, of OhioHealth, a large non-profit health system based in Ohio.

“While individual clinical scenarios can be challenging, caution should be advised in the use of gabapentinoids, particularly for those individuals who are long-term opioid users, given the lack of proven long-term efficacy and the known and unknown risks of gabapentinoid use.”

 JAMA INTERNAL MEDICINE

JAMA INTERNAL MEDICINE

Johansen’s research adds to a growing body of evidence that pregabalin and gabapentin are overprescribed and being abused. A recent study by Canadian researchers found that there was “no clear rationale” for the off-label use of the drugs and warned that they have a “significant risk of adverse effects” such as dizziness, fatigue and diminished mental activity.

Lyrica (pregabalin) and Neurontin (gabapentin) are both made by Pfizer and are two of the company’s top selling drugs, generating billions of dollars in annual sales. Lyrica is approved by the FDA to treat diabetic nerve pain, fibromyalgia, post-herpetic neuralgia caused by shingles and spinal cord injuries; while Neurontin is approved to treat epilepsy and post-herpetic neuralgia. Both drugs are also widely prescribed off label to treat back pain, depression, migraine and other conditions.

Sales of pregabalin and gabapentin have risen steadily in recent years, in part because of CDC prescribing guidelines that recommend the two drugs as alternatives to opioid pain medication. About 64 million prescriptions were written for gabapentin in the U.S. in 20l6, a 49% increase in just five years.

“We believe… that gabapentinoids are being prescribed excessively — partly in response to the opioid epidemic,” Christopher Goodman, MD, and Allan Brett, MD, recently wrote in a commentary published in The New England Journal of Medicine. “We suspect that clinicians who are desperate for alternatives to opioids have lowered their threshold for prescribing gabapentinoids to patients with various types of acute, subacute, and chronic noncancer pain.

Gabapentinoids are increasingly being used recreationally by addicts who have found the medications enhance the effects of heroin and other opioids. Lyrica and Neurontin have been linked to heroin overdoses in the United Kingdom, where prescriptions for both drugs have soared in recent years. 

Painkillers Raise Risk of Obesity and Hypertension

By Pat Anson, Editor

Commonly prescribed painkillers such as opioids and gabapentinoids  -- a class of pain medication that includes Lyrica and Neurontin – significantly raise the risk of obesity and high blood pressure, according to a large new study published in PLOS ONE.

British researchers analyzed health data on over 133,000 people, comparing the Body Mass Index (BMI), waist circumference, blood pressure and sleeping habits of patients taking pain relievers to those who did not. The study is believed to be the largest to look at the effects of painkillers on overall health.

“In the last two decades there has been a significant increase in the number of people being prescribed both opioid and non-opioid medications to treat chronic pain,” said lead author Sophie Cassidy, PhD,  a research associate at the Institute of Cellular Medicine, Newcastle University. “We already know that opiates are dependency-forming but this study also found patients taking opiates have the worst health. Obesity rates are much higher and the patients reported sleeping poorly.”

weight.jpg

Those taking opioids were 95% more likely to be obese, 82% more like to have a “very high” waist circumference and 63% more likely to have hypertension compared to the control group.  

“There could be a number of possible mechanisms by which opioids might be associated with weight gain. Sedation might decrease physical activity and therefore reduce energy expenditure, those in our cohort taking opiates were less active, and those taking both opiates and other sedative drugs were the least active. Opioids have also been shown to alter taste perception with a craving for sugar and sweet foods described,” Cassidy wrote.

“These results add further weight to calls for these chronic pain medications to be prescribed for shorter periods.”

Patients who took gabapentinoids were also more likely to be obese, have a bigger waist and higher blood pressure compared to those not taking the drugs.

Gabapentinoids are commonly prescribed as alternatives to opioids to treat neuropathy, shingles and fibromyalgia, although many patients complain about side effects such as weight gain, depression and anxiety.

As PNN has reported, gabapentinoids are also coming under scrutiny because they are increasingly being abused. Lyrica (pregabalin) and Neurontin (gabapentin) are being reclassified as controlled “Class C” substances in the UK, following a spike in the number of deaths involving the medications.

Last week, the West Virginia Board of Pharmacy designated gabapentin as a “drug of concern,” after overdoses in the state involving gabapentin rose from 36 deaths in 2012 to 106 in 2016.  Ohio, Pennsylvania and Kentucky have also reported increases in fatal overdoses involving gabapentin.

FDA Approves Extended-Release Lyrica

By Pat Anson, Editor

The U.S. Food and Drug Administration has approved a new extended-release version of Lyrica for the treatment of neuropathic pain. Lyrica CR is designed to be taken once a day, instead of the two or three doses recommended for Lyrica’s original formulation.

“Lyrica CR was developed to offer patients an effective treatment option with the convenience of once-daily dosing,” said James Rusnak, MD, Chief Development Officer in Pfizer’s Global Product Development. “It provides an important option for patients and health care providers managing these often debilitating pain conditions.”

Pfizer said the effectiveness of Lyrica CR was established in a clinical trial of over 800 patients with neuropathic pain. Patients who took Lyrica CR had a 74% reduction in pain, compared to about 55% who took a placebo. The most common side effects of Lyrica CR were dizziness, somnolence, headache, fatigue, peripheral edema, nausea, blurred vision, dry mouth and weight gain.

Lyrica (pregabalin) is one of Pfizer’s top selling drugs, but the company will likely face strong competition from cheaper generic versions of pregabalin when its U.S. patent expires next year.

Pfizer is undoubtedly hoping that current Lyrica users will switch over to the new extended release version, which will have full patent protection for many years to come. The company did not release any information on the cost of the new drug, which is expected to be available in January.

Lyrica2.jpg

Unlike the original formulation of Lyrica, which is widely prescribed to treat fibromyalgia, Lyrica CR is only approved to treat nerve pain caused by diabetic peripheral neuropathy and postherpetic neuralgia caused by shingles. But that won’t stop doctors from prescribing it off-label to fibromyalgia and other chronic pain conditions.

Pregabalin Under Scrutiny

The extended release version of Lyrica comes at a time when pregabalin is drawing new scrutiny from researchers and doctors who believe the medication is over-prescribed and being abused. Pregabalin belongs to a class of nerve drug known as gabapentinoids, which are increasingly being prescribed as alternatives to opioid pain medication.

 “We believe… that gabapentinoids are being prescribed excessively — partly in response to the opioid epidemic,” Christopher Goodman, MD, and Allan Brett, MD, recently wrote in a commentary published in The New England Journal of Medicine. “We suspect that clinicians who are desperate for alternatives to opioids have lowered their threshold for prescribing gabapentinoids to patients with various types of acute, subacute, and chronic noncancer pain.”

As PNN has reported, the World Health Organization and the FDA are also investigating reports that pregabalin is being abused. Addicts have learned pregabalin enhances the effects of heroin and other opioids.

“Reports indicate that patients are self-administering higher than recommended doses to achieve euphoria, especially patients who have a history of substance abuse, particularly opioids, and psychiatric illness. While effects of excessively high doses are generally non-lethal, gabapentinoids such as pregabalin are increasingly being identified in post-mortem toxicology analyses,” the FDA said in a recent notice published in the Federal Register.

The warning label for Lyrica CR will caution users that the drug can be abused.

“Patients should not drink alcohol while taking Lyrica CR. Patients may have more dizziness and sleepiness if taking Lyrica CR with alcohol, narcotic pain medicines, or medicines for anxiety. Patients who have had a drug or alcohol problem may be more likely to misuse Lyrica CR,” the label warns.

Pregabalin is classified as Schedule V controlled substance in the U.S., which means it has a low potential for abuse.

New Drug Discovered for Neuropathic Pain

By Pat Anson, Editor

Researchers at The University of Texas have discovered a potent non-opioid pain reliever that acts on a previously unknown pain pathway. They say the synthetic compound, known as UKH-1114, is as effective at relieving neuropathic pain in laboratory mice as gabapentin, but lasts much longer.

Now scientists need to find out if drug is safe, effective and nonaddictive in humans -- a process that could take years.

"This opens the door to having a new treatment for neuropathic pain that is not an opioid," said Stephen Martin, a chemistry professor at The University of Texas at Austin. "And that has huge implications."

UKH-1114 binds to a receptor on cells in the central nervous system called the sigma 2 receptor. Although it was discovered 25 years ago, scientists did not know what sigma 2 did until now.

bigstock-Woman-touching-her-leg-pain-20349485-300x200.jpg

Theodore Price, an associate professor of neuroscience at The University of Texas at Dallas, tested UKH-1114 on mice with nerve damage and found that it alleviated pain as well as gabapentin did, but was effective much longer -- lasting for a couple of days, compared to 4 to 6 hours. Price’s research was the first to demonstrate that the sigma 2 receptor may be a target for treating neuropathic pain.

"We started out just working on fundamental chemistry in the lab," said James Sahn, a research scientist at The University of Texas at Austin. "But now we see the possibility that our discoveries could improve the quality of people's lives. That is very satisfying."

Sahn and his colleagues have filed patent applications on the new compound. Their findings have been published in the journal ACS Chemical Neuroscience. An earlier paper on the sigma 2 receptor was published in the journal Proceedings of the National Academy of Sciences.

Chronic neuropathic pain is caused when nerves in the central nervous system are damaged by chemotherapy, shingles, diabetes or injuries to the brain or spinal cord. About 8% of adults worldwide suffer from some form of neuropathy.

Diabetic peripheral neuropathy causes nerves to send out abnormal signals. Patients can feel stinging or burning pain, as well as loss of feeling, in their toes, feet, legs, hands and arms. Nearly 26 million Americans have diabetes and about half have neuropathy, according to the American Diabetes Association. 

Many patients say drugs commonly used to treat neuropathic pain, such as gabapentin (Neurontin) and pregabalin (Lyrica), either don’t work or have unpleasant side effects such as dizziness, fatigue and diminished cognitive ability. Some doctors also feel the drugs are being overprescribed as alternatives to opioid pain medication.  

Lyrica and Neurontin Face More Scrutiny

By Pat Anson, Editor

The safety and effectiveness of Lyrica (pregabalin) and Neurontin (gabapentin) – two non-opioid drugs widely used to treat chronic pain – are drawing new scrutiny from researchers and doctors who believe the medications are over-prescribed.

In a study published in PLOS Medicine, Canadian researchers say there is little evidence that gabapentinoids – a class of nerve medication that includes Neurontin and Lyrica – are effective in treating chronic low back pain. In their review of 8 clinical studies, the researchers also found the drugs have a “significant risk of adverse effects.”

Lyrica and Neurontin are commonly prescribed for fibromyalgia and neuropathic pain, but the researchers say the drugs are increasingly prescribed for chronic back pain, even though there is “no clear rationale” for it.

"Despite their widespread use, our systematic review with meta-analysis found that there are very few randomized controlled trials that have attempted to assess the benefit of using gabapentin or pregabalin in patients of chronic low back pain," wrote lead author Harsha Shanthanna, MD, an assistant professor at McMaster University in Hamilton, Ontario.

"They necessitate prolonged use and are associated with adverse effects and increased costs. Recent guidelines from the National Health Service (NHS), England, expressed concerns on their off-label use, in addition to the risk of misuse.”

Shanthanna and his colleagues found that gabapentin showed “minimal improvement” in back pain compared to a placebo and pregabalin was “inferior” compared to other analgesics. There were no deaths or hospitalizations reported in any of the studies, but both drugs were associated with increased risk of dizziness, fatigue, visual disturbances, and diminished mental activity.

Lyrica and Neurontin are both made by Pfizer and are two of the company’s top selling drugs, generating billions of dollars in sales annually. Lyrica is approved by the FDA to treat diabetic nerve pain, fibromyalgia, post-herpetic neuralgia caused by shingles, and spinal cord injuries. It is also prescribed off-label to treat other chronic pain conditions, including lower back pain.

Neurontin is only approved by the FDA to treat epilepsy and neuropathic pain caused by shingles, but is widely prescribed off label to treat depression, ADHD, migraine, fibromyalgia and bipolar disorder. According to one estimate, over 90% of Neurontin sales are for off-label uses. Pfizer has paid $945 million in fines to resolve criminal and civil charges that it marketed Neurontin off-label to treat conditions it was not approved for.

Sales of pregabalin and gabapentin have risen steadily in recent years, in part because of CDC prescribing guidelines that recommend the two drugs as alternatives to opioid pain medication. About 64 million prescriptions were written for gabapentin in the U.S. last year, a 49% increase since 2011.

“We believe… that gabapentinoids are being prescribed excessively — partly in response to the opioid epidemic,” Christopher Goodman, MD, and Allan Brett, MD, recently wrote in a commentary published in The New England Journal of Medicine. “We suspect that clinicians who are desperate for alternatives to opioids have lowered their threshold for prescribing gabapentinoids to patients with various types of acute, subacute, and chronic noncancer pain.

“Patients who are in pain deserve empathy, understanding, time, and attention. We believe some of them may benefit from a therapeutic trial of gabapentin or pregabalin for off-label indications, and we support robust efforts to limit opioid prescribing. Nevertheless, clinicians shouldn’t assume that gabapentinoids are an effective approach for most pain syndromes or a routinely appropriate substitute for opioids.”

FDA Seeks Public Comment on Abuse of Lyrica

The U.S. Food and Drug Administration announced last week that it was seeking public comment on reports that pregabalin is being abused. The FDA action was in response to a formal notification from the World Health Organization (WHO) that it may place international restrictions on pregabalin to reduce the risk of abuse and diversion. The FDA has until September 30 to respond to WHO.

Reports indicate that patients are self-administering higher than recommended doses to achieve euphoria, especially patients who have a history of substance abuse, particularly opioids, and psychiatric illness. While effects of excessively high doses are generally non-lethal, gabapentinoids such as pregabalin are increasingly being identified in post-mortem toxicology analyses,” the FDA said in a notice published in the Federal Register.

Pregabalin is already classified as Schedule V controlled substance in the U.S. under the Controlled Substances Act, which means the DEA considers it to have a low potential for abuse.

The idea that Lyrica and Neurontin are being abused is surprising to many patients and doctors, but there are growing signs the drugs are being used recreationally.

Both Lyrica and Neurontin have been linked to heroin overdoses in England and Wales, where prescriptions for both drugs have soared in recent years.  Addicts have apparently found the medications enhance the effects of heroin and other opioids.

A small study of urine samples from patients being treated at U.S. pain clinics and addiction treatment centers found that one in five patients were taking gabapentin without a prescription.

Gabapentin and pregabalin are also being abused by prison inmates, according to Jeffrey Keller, MD, chief medical officer of Centurion, a private corrections company. 

“Gabapentin is the single biggest problem drug of abuse in many correctional systems,” Keller recently wrote in Corrections.com. “There is little difference (in my opinion) between Lyrica and gabapentin in both use for neuropathic pain or for abuse potential.”

Pfizer did not respond to a request for comment.