Q. I would like to know your feelings on the regular use of gabapentin for chronic insomnia. As a long time suffer of insomnia, my doctor has prescribed a myriad of drugs. Most recently upwards of 3600 mg of gabapentin 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 (Neurontin) was originally developed as an anti-seizure drug. It 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).
Pfizer, the manufacturer of the brand name Neurontin, got into major trouble when it marketed this drug for off-label uses. A company is not allowed to promote a medicine for things that the FDA has 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 for alleviating nerve pain caused by shingles (postherpetic neuralgia).
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. 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.
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 Side Effects:
- Dizziness, vertigo
- Fatigue and or tiredness
- Unsteadiness or incoordination
- Abnormal thinking, anxiety, hostility, confusion, amnesia,
- Depression, suicidal thoughts, mood changes
- Fluid accumulation in feet, edema of face or extremities
- Digestive distress, indigestion, loss of appetite, gas, nausea, vomiting, diarrhea
- Dry mouth, dental problems, gingivitis
- Blurred vision, double vision, unusual eye movements (nystagmus)
- Withdrawal seizures (never stop gabapentin suddenly!)
- Blood disorders
- Skin rash (alert your M.D. immediately if this occurs!)
- Upper respiratory tract infections, fever
- High blood pressure
- Tremor, jerky movements
- Joint pain, joint stiffness, arthritis
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.
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. We are surprised that your doctor prescribed such a heavy-duty drug for insomnia, especially at such a high dose. The “normal” dose of gabapentin for treating epilepsy or shingles pain would be up to 1800 mg daily. Although 3600 mg is sometimes prescribed, it would have to be considered a high dose, especially for an unapproved use.
Since you report that gabapentin is affecting the quality of your life in a negative way, perhaps it is time to talk to your doctor about reconsidering this drug and discussing a gradual withdrawal process. You may need to consult a sleep specialist to help you deal with your chronic insomnia in a more integrative manner.