Surprising Gabapentin Side Effects

The Food and Drug Administration first approved Neurontin (gabapentin) in 1993 to treat epilepsy. Anticonvulsants are not normally blockbuster drugs. Perhaps that is why the original manufacturer, Parke-Davis, promoted the drug off-label to treat pain. You will read about the mischief that caused shortly. The marketing campaign was incredibly successful, though. Gabapentin has become one of the most frequently prescribed pain pills in America. Over 10.5 million patients take it daily. Prescriptions are up, in large part because doctors have cut back on opioid prescribing. Do doctors adequately warn patients about gabapentin side effects and withdrawal reactions? There is a new and unexpected complication: COPD (chronic obstructive pulmonary disease).

COPD: An Unexpected and Worrisome Complication!

Most people are swallowing gabapentin for conditions that the FDA has never approved and for which there may be modest scientific support. We would not get overly concerned with this off-label prescribing if this drug were perfectly safe. But gabapentin side effects are not trivial, as you will read. And a brand new gabapentin side effect has just emerged.

Canadian researchers have just dropped a bombshell on gabapentin (Annals of Internal Medicine, Jan. 15, 2024). They compared patients taking gabapentinoids (gabapentin and pregabalin) with “nonusers.” This was a big database!

• There were 356 gabapentinoid users with epilepsy
• There were 9,411 gabapentinoid users with nerve pain
• There were 3,737 gabapentinoid users with chronic pain

These patients were matched 1:1 to similar people not taking gabapentinoids.

The authors point out that published studies:

“…have shown severe breathing difficulties in some patients using gabapentinoids.

“This safety issue may be of particular concern in patients with respiratory disease, such as chronic obstructive pulmonary disease (COPD).”

Here is what they found:

“In this population-based cohort study of patients with COPD, gabapentinoid use was associated with increased risk for severe exacerbation in patients with  epilepsy, neuropathic pain, and other chronic pain. The increased risk was observed regardless of age, sex, and various markers of COPD severity. Gabapentinoid use may also be associated with increased risks for moderate or severe exacerbation and respiratory failure.”

The FDA does list “serious breathing problems” in the official prescribing information for gabapentin:

“Serious breathing problems can occur when NEURONTIN is taken with other medicines that can cause severe sleepiness or decreased awareness, or when it is taken by someone who already has breathing problems. Watch for increased sleepiness or decreased breathing when starting NEURONTIN or when the dose is increased. Get help right away if breathing problems occur.”

We worry, though, that many health professionals may not warn patients who have COPD or other “breathing problems” that gabapentinoids could be dangerous.

Off-Label Prescribing of Gabapentin:

Approved and Unapproved Uses of Gabapentin:

There are only two FDA-sanctioned uses for gabapentin:

• “Management of postherpetic neuralgia in adults
• Adjunctive therapy in the treatment of partial onset seizures, with and without secondary generalization, in adults and pediatric patients 3 years and older with epilepsy”

“Postherpetic neuralgia” is the lingering nerve pain after a shingles attack.

That’s it! The FDA has not approved this drug for any other “indication.”

Despite the lack of FDA approval, doctors prescribe gabapentin for (Substance Abuse: Research and Treatment, Sept. 23, 2018):

• Attention deficit disorder (ADD/ADHD)
• Fibromyalgia
• Mental illness
• Migraines
• Substance dependence
• Neuropathic pain
• Restless leg syndrome (RLS)
• Bipolar disorder (BPD)
• Diabetic nerve pain
• Premenstrual syndrome (PMS)
• Postoperative pain
• Etc.

Gabapentin for Postoperative Pain:

Because there has been such concern about opioid abuse, many surgeons are now fearful about prescribing drugs such as oxycodone (Oxycontin, Percocet) or hydrocodone (Vicodin). The theory is that gabapentin will provide enough postoperative pain relief that doctors can prescribe a lower dose of opioid for a shorter period of time. That is supposed to reduce the risk of opioid dependence.

A study published in JAMA Internal Medicine (Nov. 1, 2022) reports that:

“…reductions in pain intensity 24 hours after surgery and opioid-related adverse events associated with gabapentin and placebo were inconsistent and not clinically meaningful.”

The authors reported about gabapentin side effects:

“…perioperative gabapentin use was associated with modestly increased risk of delirium, new antipsychotic use, and pneumonia but not with in-hospital death among adults aged 65 years or older after major surgery. Considering the increasing number of major surgeries performed in older adults and the negative consequences of perioperative delirium, our findings raise concern about an increasingly adopted clinical practice that involves routine use of gabapentin as part of multimodal analgesia.”

The Cochrane Database of Systematic Reviews (May 12, 2010) concluded that using gabapentin for the treatment of acute postoperative pain:

“…is of limited clinical value and inferior to commonly used analgesics.”

Gabapentin After Knee Surgery:

A reader of our syndicated newspaper column asked about gabapentin side effects:

Q. When I had knee replacement surgery, I was prescribed gabapentin to help control pain. It caused brain fog, imbalance, sleepiness and depression. Why wasn’t I warned about these complications?

A. Doctors are increasingly prescribing gabapentin to reduce opioid use following surgery. A study published in JAMA Internal Medicine (Nov. 1, 2022) indicates that older people may not tolerate this drug well.  They often report side effects similar to those you experienced. Doctors should warn patients about such adverse reactions.

Gabapentin for Knee Osteoarthritis:

Some doctors are prescribing gabapentin for knee pain associated with osteoarthritis. A study published in the Journal Osteoarthritis and Cartilage (Feb. 2023) concludes:

“Incorporating gabapentin into care for patients with knee OA [osteoarthritis] does not appear to offer good value.”

Gabapentin for Back Pain:

Q. My doctor prescribed gabapentin for severe back pain. It affected my vision and caused muddled thinking and loss of concentration and coordination. After I’d been on it for two months, my husband said, “What is going on? You’ve never been this way before.” After 30 years together, he knows me pretty well.

When I talked to the doctor about gabapentin side effects, he said he knew about them but didn’t want to scare me off taking it!

I stopped taking gabapentin and got my brain back. Then I started a regimen of targeted stretching and diet changes, along with some chiropractic care. My back has never felt better. To me it seems unethical for a doctor NOT to tell a patient about potential gabapentin side effects.

A. Many other readers have complained of brain fog or fuzzy thinking when taking gabapentin. No one should ever stop this drug abruptly, however. The FDA requires this in the official prescribing information:

“Adverse reactions following the abrupt discontinuation of gabapentin have also been reported. The most frequently reported reactions were anxiety, insomnia, nausea, pain, and sweating.”

If it is necessary to stop this drug, it should be done gradually under medical supervision.

How Well Does Gabapentin Work for Back Pain?

A systematic review and meta-analysis of this drug for pain and disability associated with sciatica was published in Atencion Primaria (Jan. 2022). The authors conclude:

“Our results are consistent with previous systematic reviews assessing the effectiveness of anticonvulsants on low and back pain relief. Their findings reflect that these drugs were related to a higher risk for AE [adverse effects] and were ineffective both for the treatment of pain associated with acute sciatica and functional disability.”

“In this review, no evidence has been found to support the use of pregabalin [Lyrica] or gabapentin for sciatica pain or low back pain, since the effect is not superior to placebo. In addition, adverse effects of different considerations associated with their use have been reported. In view of this, its routine clinical use cannot be supported.”

Gabapentin for “Pins and Needles”:

Female foot above colored pushpin, metal sharp pin

Q. About fifteen years ago, I was experiencing significant pins and needles sensations in my hands and feet and was diagnosed with MS. I was prescribed gabapentin for the discomfort. I kept taking the gabapentin and over the years I became progressively weaker and more fatigued. Then I began seeing specialists for bladder issues, among other things. I fully expected to end up in a nursing home within ten years.

Then I weaned myself from the gabapentin and noticed I was regaining strength and energy. I have now returned to living a totally normal, active life with my only symptoms being pins and needles. Careful use of supplements has helped reduce this too.

It scares me to think I might never have discovered the true cause of my disability. How many people are also living with a disease induced by medication?

A. Thank you for your insightful story. Gabapentin (Neurontin) has FDA approval to treat epilepsy and nerve pain after a shingles attack (postherpetic neuralgia). Doctors do prescribe it off-label for many other conditions, though. Side effects include weakness, fatigue, sleepiness, dizziness and depression. By the way, the official prescribing information lists “asthenia” as one of the important gabapentin side effects. Asthenia means “abnormal physical weakness or lack of energy” (RxList).

Gabapentin for Insomnia:

Alarm clock in the middle of the night isolated on black concept for insomnia or sleepless night

Q. I would like to know your feelings on the regular use of gabapentin for chronic insomnia. My doctor has prescribed a myriad of drugs to treat my long-term insomnia. Most recently, he prescribed upwards of 3600 mg of gabapentin to be taken at bedtime.

After more than 6 months of use I have noticed that gabapentin is taking a toll on my quality of life. Your thoughts please!

A. Gabapentin was approved by the FDA as an “add-on” treatment for patients with epilepsy in 1993. Although researchers do not completely understand how gabapentin works to control seizures, they think it affects production of a neurochemical in the brain called GABA (gamma-aminobutyric acid). It has never been approved for treating insomnia!

The Off-Label Marketing Boondoggle:

Parke-Davis was acquired by Warner-Lambert in 1974. Pfizer acquired the whole company in 2000.

The manufacturer of brand name Neurontin, got into major trouble when it marketed the drug for off-label uses. Pharmaceutical manufacturers were not allowed to promote their medicines for indications that the FDA had not approved. In Pfizer’s case, these unofficial uses for Neurontin included bipolar disorder, alcohol withdrawal, migraines and pain. The company eventually paid $430 million in penalties and admitted to fraudulent promotion.

We mention this because Neurontin is currently available generically as gabapentin. In addition to treating epilepsy, the drug now has official FDA approval only for alleviating nerve pain caused by shingles (postherpetic neuralgia).

Off-Label Prescribing Continues:

Even though gabapentin does not have the FDA’s blessing for treating other kinds of nerve pain (neuropathy), many doctors are using it for this purpose. Some physicians prescribe it to patients with fibromyalgia and migraines as well as to control hot flashes brought on by menopause, even though there is no official blessing from the FDA. It is estimated that 95% of the prescriptions filled for gabapentin are for unapproved off-label uses.

This is not illegal. Doctors can prescribe any drug for any reason they see fit. That said, we could find little evidence to suggest that gabapentin would be helpful for insomnia. This is definitely an “off-label” use if ever there was one. No organization is responsible for monitoring irresponsible off-label prescribing…not the FDA, the AMA, or any medical specialty group. Patients are on their own to find out if their doctors are prescribing a drug responsibly.

A review in the journal Substance Abuse: Research and Treatment (Sept. 23, 2018) puts off-label prescribing of gabapentin into perspective:

“Gabapentin has several potential therapeutic uses and may represent a safer option versus alternative agents in some of these indications, so the intent of this analysis is not to condemn its use. However, it is prudent to recognize that gabapentin has seen high rates of off-label use and increased prescribing in recent years, which fails to align with current evidence regarding efficacy. Indeed, most of the evidence for off-label use is limited to a few small, low-quality studies, often with data only weakly supporting use. Higher quality evidence, which indicates gabapentin nonefficacy, is often lost in the shuffle. Given the increasing reports of abuse and evidence of potential harms associated with gabapentin use, it is important to realize the potential risks associated with this medication and weigh these risks against this lack of reliable evidence purporting its efficacy for many of its off-label uses.”

Gabapentin Side Effects:

If there were few, if any, side effects associated with gabapentin we would not worry too much about the prescribing of this drug for so many off-label uses. But gabapentin has some potentially worrisome adverse effects.

The FDA has issued this warning:

“Antiepileptic drugs (AEDs), including Neurontin [gabapentin], increase the risk of suicidal thoughts or behavior in patients taking these drugs for any indication. Patients treated with any AED for any indication should be monitored for the emergence or worsening of depression, suicidal thoughts or behavior, and/or any unusual changes in mood or behavior.”

The FDA also mentions an “unexpectedly high incidence of pancreatic acinar adenocarcinomas” [cancer] in male rats that received gabapentin. The agency adds the unhelpful caveat that the:

“clinical significance of this finding is unknown.”

In other words, no one knows whether this animal research means that men will be at higher risk for pancreatic cancer. This is not the sort of thing that the FDA requires drug companies to follow up on because the long-term research needed to detect a cancer signal can be quite challenging and expensive.

Gabapentin Discontinuation Syndrome (aka Withdrawal):

No one should ever discontinue gabapentin abruptly. Like so many medications that affect the central nervous system, sudden withdrawal may lead to unexpected side effects. Some that have been reported include anxiety, insomnia, nausea, pain, sweating and even seizures. Sadly, though, the FDA gives very little guidance to prescribers about how to gradually taper patients off gabapentin.

Stories from Readers:

When you read a long list of gabapentin side effects like those listed above, your eyes glaze over almost instantly. Drug companies have recognized this, which is why there is so much prescription drug advertising on TV and in magazines. There was a time when the pharmaceutical industry worried about telling patients about such serious side effects as irregular heart rhythms, hypertension, cancer or blood disorders. Not any more. They realize that even warnings about heart attacks, strokes or death do not scare people away.

The only way we can help you understand what such side effects are like in real life is to share stories from visitors to this website. Here are just a handful. You can read hundreds more in the comment section at the bottom of this article.

Sue in Corvallis, Oregon, writes about her husband:

“My husband has been on gabapentin for anxiety and depression for over 3 years now. The doctors started him on this to get him off the benzodiazepines he had been on for 20 years.

“While it seemed to help in the beginning, they kept increasing the dose. He is currently on 2700 mg per day (900 mg x 3). That is way too much.

He has changed so much – cries hysterically, has mood swings, goes from insomnia to sleep deprivation. He has tremors, blurred vision and now talks about suicide all the time. He is so discouraged.

“If the FDA has not okayed gabapentin for anxiety and depression, why do docs prescribe it? I am ready to complain to the drug company! He and I just want his life back. Lying in bed 85% of the time is not helpful.”

Susan in Milton, Florida, shares a tragic story:

“My boyfriend was prescribed gabapentin for his diabetic neuropathy. I can see now that he became more withdrawn and one evening left the house without my knowledge and went to the hospital where they prescribed sertraline (Zoloft) and counseling the following Monday.

“He committed suicide Saturday morning. If I had been told by his doctor about the side effects of gabapentin I could have done something to prevent his death.”

Lynn in Mobile, Alabama, warns about weight gain from gabapentin (she isn’t the only one):

“I have been on gabapentin (800 mg 3 x daily) for about 13 years. It was prescribed for spinal problems and pain problems in general. When I first started gabapentin, it  worked great. But I experienced a tremendous amount of weight gain, like close to 100 pounds!

“As time has gone on I have noticed my life has changed so much. I have developed random weird thoughts. I never want to go anywhere or do anything except sit in my recliner and watch tv.

“I feel a nervous wreck if it’s been awhile since I have taken my gabapentin. I have an overwhelming feeling sometimes, like a flash in my mind of suicidal thoughts. My mind feels scrambled. It is very hard to explain.

“My pain is so unbearable sometimes that I am afraid to get off gabapentin. I am 44 years old and weighing around 250 pounds! I look horrible and don’t want anyone to see me period.”

Jonanne in England has had trouble getting off gabapentin:

“I had been on gabapentin for about two years for nerve damage from gallbladder surgery. I was on 300 mg 3 times a day. These tabs were a wonder drug and took my pain away almost immediately.

“Now two years later I returned to the doctor and told her I would like to come off this medication as I feel it’s time. For the last few weeks she weaned me off them with a withdrawal chart, which I followed till the last tablet. Just two days after being completely off gabapentin the side effects have hit me: dizziness, headaches, nausea, and I actually fainted, which I have never done before in my life.

“The doctor told me I had come off gabapentin too quickly and to start taking a lower dosage. I started weaning myself off gabapentin  gradually again, but still the same symptoms. I have not taken any pills for 5 days and the dizziness and headaches are back. I am not sleeping. I am also having hot sweats in the night and feeling very low in mood. I am not going back on gabapentin! I am going to persevere even with these symptoms and hope I can cope. I feel like I am going around the bend and will never get better.”

The People’s Pharmacy Bottom Line:

Gabapentin is an effective treatment for epilepsy and the excruciating pain that sometimes lingers after an attack of shingles. Although it is quite frequently prescribed for off-label uses, the benefit/risk ratio is not clear. The drug has many potentially serious side effects. And researchers are discovering new ones as demonstrated by the Canadian researchers who announced that gabapentin can trigger serious worsening of chronic obstructive pulmonary disease. By the way, the most extreme exacerbations of COPD happened about six months after patients started regular gabapentinoid use.

The “normal” dose of gabapentin for treating epilepsy or shingles pain would be up to 1800 mg daily. Reading that a doctor prescribes 3600 mg for an unapproved use like insomnia scares the heck out of us.

No one should ever stop gabapentin suddenly. If gabapentin side effects become problematic, a VERY gradual withdrawal process under medical supervision is necessary.

Is Marijuana an Alternative to Gabapentin?

People with nerve pain may find our one-hour interview with David Casserett, MD, quite fascinating. In it he talks about medical marijuana for “neuropathic” pain. It is titled, “How One Doctor Changed His Mind About Medical Marijuana.”

If you are worried about the psychoactive properties of marijuana, you may find this article about cannabidiol (CBD) oil of substantial interest. It may ease nerve pain without causing people to get “high.”