Disclaimer: None of the information in this article constitutes medical advice, and is just the opinion of the writer(s) and published for informational purposes only. We recommend that patients follow their doctor’s guidance in regard to prescription medication.
Gabapentin is one of the most commonly-prescribed medications in the world, and it’s used primarily to treat seizures. It’s the generic version of the drug, and the brand-name version in the U.S. is called FusePaq Fanatrex, Gabarone, Gralise or Neurontin. These terms all refer to the same active ingredient, so we will refer to them interchangeably throughout this article.
In this article we’ll review the medical research on gabapentin to determine if we believe it to be safe and effective for treating seizures. We’ll also highlight side effects of the drug, dosage information and discuss whether it can be used to treat animals with seizure disorders.
Does Gabapentin Work?
Gabapentin has been studied extensively in clinical trials spanning decades. As one example, a medical trial from 2003 examined the efficacy of gabapentin for the treatment of epilepsy, which is a condition that causes seizures.
Patients were prescribed either gabapentin at 1,200 milligrams (mg) per day, gabapentin at 1,800 mg per day or a placebo pill. Both of the groups taking gabapentin had seizures drop by more than 10% the rate of those taking placebo. The higher-dose gabapentin group experienced around 5% fewer seizures than the lower-dose gabapentin group.
A separate medical trial tested whether gabapentin was effective for treating seizures in children. A group of children who experienced regular seizures were prescribed gabapentin.. Around 50% of the patients taking gabapentin experienced a 25% or greater reduction in seizures.
By the end of the trial, two patients (out of 32 total) taking gabapentin had a total reduction in their symptoms and were seizure-free, and four patients were only experiencing seizures once every few months (categorized as “almost seizure-free”).
Gabapentin has also been proven effective in treating a specific category of seizures called partial-onset seizures. This condition involves seizures which only affect one part of the brain instead of the entire brain. The trial, which was published in the Epilepsea medical journal, used gabapentin as a monotherapy (sole type of therapy) for treating partial-onset seizures.
The group taking gabapentin experienced a statistically significant reduction in partial-onset seizures, and the study authors concluded that the data “provide[s] good evidence of the efficacy and safety of gabapentin.”
We can conclude from the available evidence that gabapentin is effective for treating seizures.
How Does Gabapentin Work?
One interesting thing about gabapentin is that researchers don’t know exactly how it works. Even the StatPearls database, which is a medical database maintained by the U.S. government, describes gabapentin’s mechanism of action in the following way: “The exact mechanism of action with the GABA receptors is unknown.”
Sometimes pharmaceutical compounds can be found effective based on clinical trials without scientists knowing their exact biochemical effect. If a drug causes patients’ mood to improve by 30%, it may qualify for approval to treat depression even if researchers are unclear how it works.
The brain is incredibly complex, and there are millions of synergies and interactions between different chemicals and electrical signals, and sometimes it can be challenging to parse out exactly what downstream effects a medication causes.
A separate medical review suggested that gabapentin may work by modifying the function of voltage-sensitive calcium channels in the brain.
Gabapentin Side Effects
Gabapentin does cause side effects in some patients, as nearly all pharmaceutical medications do, but it doesn’t carry a black box warning, which is the most severe level of warning from the Food and Drug Administration (FDA) in the U.S. This is a good sign, as many pharmaceutical medications we’ve reviewed recently, such as Pristiq, carried black box warnings on their label.
In 2019 the FDA published a warning letter about gabapentin side effects, indicating to patients that the medication may cause serious breathing problems. The letter detailed that patients with “respiratory risk factors” such as chronic obstructive pulmonary disease (COPD) were at risk of this side effect.
A medical review of gabapentin side effects was published in the American Journal of Geriatric Psychiatry in 2004. It pooled data from three individual trials to report on the most common side effects.
Interestingly, patients at lower doses of gabapentin experienced higher rates of certain side effects. Patients taking a dose under 1,800 mg of gabapentin experienced dizziness over 20% of the time, which was much higher than placebo. Patients at this dose also reported daytime sleepiness as a side effect 14.9% of the time, which was 9.1% higher than the placebo group.
The more concerning side effect noted in this trial was in the higher-dose gabapentin group. Those taking a dose over 1,800 mg per day were more likely to experience peripheral edema, which is swelling of the extremities. 7.5% of patients at this dose experienced this side effect.
Another side effect reported in a separate medical review of gabapentin is myoclonus. This is the medical term for muscle jerking. The researchers report that 1.9% of patients taking gabapentin in a medical study experienced this side effect, but that it was resolved when medication was stopped, suggesting this effect is reversible.
Gabapentin is prescribed at a wide range of doses based on condition and severity of condition. The StatPearls database referenced earlier in this review lists the dose for seizure to range between 300 mg and 1,200 mg taken three times per day, which results in a cumulative daily dose between 900 mg and 3,600 mg.
The dose is lower for those prescribed gabapentin for fibromyalgia, ranging 400 mg to 800 mg taken three times daily, resulting in a cumulative daily dose between 1,200 and 2,400 mg.
Gabapentin is also prescribed for neuropathic pain, which is the medical term for nerve pain which can affect nerves throughout the body. The dose range for this condition is the same as the dose range for seizures: between 900 mg and 3,600 mg per day, divided into three oral doses.
A medical study documents that gabapentin is cleared via renal (kidney) excretion, so dosage is typically lower for patients with kidney disease, so as not to overburden the kidneys.
Should I Take Branded Or Generic Gabapentin?
As referenced in the intro to this article, gabapentin is the generic name of a drug that’s branded in the U.S. as one of the following medications: FusePaq Fanatrex, Gabarone, Gralisek Neurontin.
All of these drugs have the exact same active ingredient: gabapentin.
A medical study examined whether gabapentin generic or branded was more effective, and the researchers determined that the drugs were equally effective. This should be logically unsurprising, given that they contain the same active ingredient. Unless there were quality control issues with the generic product manufacturing, there’s no reason for a branded version of a drug to be more effective than the generic version.
We typically recommend that patients speak with their doctor about the generic version of drugs (in this case gabapentin) instead of the brand-name version, because it’s likely to be equally effective and significantly cheaper.
Gabapentin may interact with various other drugs, as detailed by its FDA information label.
The label contains a “Drug Interactions” section which indicates that gabapentin may interact with hydrocodone and morphine, which are both opioids. This suggests that patients taking gabapentin should be sure to indicate such if they receive treatment in urgent care or an emergency room, because both opioids listed can be used in these settings.
Gabapentin also interacts with an over-the-counter (OTC) antacid called Maalox. The antacid reduces the bioavailability of gabapentin by 20%, which may make the drug less effective.
Gabapentin may also interact with urinary protein tests. The gabapentin label indicates that the drug cause false positive readings on a specific dipstick test for urinary protein levels, which indicates that patients taking gabapentin should be sure to notify their doctor before taking any test for urinary protein to ensure accurate results.
Is Gabapentin A Controlled Substance?
Gabapentin has a unique legality for a pharmaceutical medication. A controlled substance means a substance which is illegal in the United States, such as cocaine.
Gabapentin is not a controlled substance federally, according to the Drug and Enforcement Agency (DEA). However, the medication is a controlled substance in an increasing number of states. Even though the drug is federally legal, users in states where it’s illegal on the state level, due to its inclusion on the controlled substances list, may be subject to legal action.
A Pharmacy Today review indicates that gabapentin is a controlled substance in the following states: Alaska, Kentucky, Michigan, North Dakota, Tennessee, Virginia and West Virginia.
There’s also been a recent push by both the FDA and the DEA to make gabapentin a federally controlled substance due to potential for abuse and misuse.
Patients in states where gabapentin is a controlled substance should seek legal counsel before handling the substance even if it’s prescribed by a medical professional.
Is Gabapentin Addictive?
Whether or not a drug is addictive is a complex medical issue, because it can vary so much patient-to-patient. An extremely thorough medical review analyzed the addictive potential of gabapentin by examining results from 106 individual medical studies on the drug.
The researchers concluded the following:
“We did not find convincing evidence of a vigorous addictive power of gabapentinoids which is primarily suggested from their limited rewarding properties, marginal notes on relapses, and the very few cases with gabapentinoid-related behavioral dependence symptoms (ICD-10) in patients without a prior abuse history.”
A separate study suggested that gabapentin could induce drug-seeking behavior due to its effects on dopamine, which is a neurotransmitter associated with pleasure and reward seeking. However, this study used an animal model so the quality of evidence is lower than the previous study which examined human data.
We recommend that patients with a history of addiction speak with their doctor about the risks of Gabapentin’s addictive potential, because the risk seems higher in those who are predisposed to addiction.
Can Gabapentin Treat Anxiety?
Gabapentin is not approved by the FDA for treating anxiety, so such use is an off-label use, and one we would not recommend. Some doctors prescribe drugs for off-label uses.
A medical study from 2012 tested the efficacy of gabapentin for anxiety reduction in breast cancer survivors. Patients either took daily gabapentin at 300 mg, daily gabapentin at 900 mg, or a placebo pill.
Both trial participant groups taking gabapentin had significantly reduced anxiety compared to the placebo group. Interestingly, the lower dose was more effective for anxiety reduction. Both medication groups experienced more than double the anxiety-reduction effect of the placebo group.
A separate case study published in the Case Reports for Psychiatry medical journal documented a 59 year old woman who was prescribed gabapentin for anxiety. The drug was effective in treating her Generalized Anxiety Disorder (GAD) symptoms.
This early research suggests that gabapentin may be effective for treating anxiety, but more medical studies are needed to establish so conclusively. The FDA may approve gabapentin for treatment of anxiety if more research emerges proving its efficacy.
Can Gabapentin Cause Withdrawal Symptoms?
Gabapentin can cause withdrawal symptoms, and is documented to do so in some patients in medical research. A case report published in the Annals of Pharmacotherapy journal documents a 76 year old woman who developed akathisia while withdrawing from gabapentin. This condition refers to the inability to remain still, and can be quite uncomfortable. The condition eventually resolved itself after 3 days.
Another medical review documents 18 case reports of patients who experienced addition to or withdrawal symptoms from use of gabapentin. The study authors listed “a history of alcohol or substance abuse” as a risk factor for dependence issues.
Withdrawal symptoms varied, but the most common were confusion and disorientation (experienced in 45% of withdrawal cases), excessive sweating (36%) and gastrointestinal symptoms (23%).
Because gabapentin can cause discomforting withdrawal symptoms, it’s important for patients considering stopping use of the medication to speak with their doctor first, because tapering off according to medical standards can make the quitting process safer and less painful.
Does Gabapentin Cause Weight Gain?
Use of gabapentin is associated with weight gain on average. A medical review titled “Drugs Commonly Associated With Weight Change” which was published in the well-respected JECM journal documents that gabapentin is associated with 2.2 kilograms (kg) of weight gain, which equates to 4.85 pounds (lbs), after 1.5 months of use.
It’s unclear what causes this association, and whether gabapentin is directly a cause of weight gain or if it causes downstream biological effects which cause weight gain.
Gabapentin And Alcohol
Gabapentin is sometimes prescribed for reducing alcohol cravings and ameliorating dependence on alcohol. A clinical study on gabapentin for treating alcohol dependence found that the drug was effective.
Only 4.1% of alcoholic patients on a placebo pill were able to fully abstain from alcohol use during the trial, while 11.1% of patients taking 900 mg gabapentin and 17% of patients taking 1,800 mg gabapentin were able to fully abstain.
Gabapentin’s FDA label, which we linked to earlier, also notes there are contraindications of using alcohol while on the drug. Alcohol should not be used while taking gabapentin unless approved otherwise by a doctor.
Can Gabapentin Be Used For Dogs?
Because older dogs often suffer from seizures and nerve pain, many consumers want to know whether gabapentin is an effective treatment.
It can be difficult to measure pain in animals, but a clinical trial on gabapentin for post-operative pain management in dogs attempted to do so. The researchers used morphine administration as a proxy for the dogs’ pain: more morphine required suggested more pain, and less morphine required suggested less pain.
The dogs in the study were given morphine based on whether they were agitated and in visible distress, which is how the vets qualified pain. The dogs receiving gabapentin required significantly less morphine, suggesting that gabapentin may be effective for reducing pain in dogs.
A separate clinical trial evaluated the effects of gabapentin on dogs with seizures. 6 of the 11 dogs studied experienced a positive response to the drug, with the average number of seizures per week and the average number of days without a seizure per week decreasing by the end of the study.
These medical results suggest that gabapentin may be effective for treating seizures and pain in dogs, but we strongly recommend only giving gabapentin to a dog if the medication was prescribed by a veterinarian. Dosage differs between humans and dogs, and there may be other medical considerations that would put an animal’s life at risk if their owner were to give the animal a human dose of gabapentin.