Gabapentin is an anticonvulsant that is sometimes used to treat epilepsy. It also may be used to lessen symptoms of postherpetic neuralgia, a complication of shingles that affects your nerve fibers and skin and causes burning pain. It’s been prescribed for peripheral neuropathy, a painful complication of diabetes, as well. Though your liver does not metabolize this drug, there have been a few case reports of abnormal liver function tests associated with it.
Gabapentin affects nerves and chemicals in your body that are involved in some types of pain and in seizures. Drug manufacturer Pfizer classifies abnormal liver function tests as an infrequent side effect for gabapentin. There is insufficient data to estimate incidence for these or establish whether gabapentin is the sole cause of elevated liver function tests, notes Pfizer. Gabapentin is not metabolized by the liver. Instead, it is excreted unchanged in your kidneys after circulating in your blood.
One case of gabapentin-induced liver toxicity is reported in the September 2002 edition of “BMJ.” The drug was being used to treat a 50-year-old man suffering from diabetic peripheral neuropathy. The man developed liver problems after taking the drug for two weeks, according to the case report. Symptoms included dark urine, jaundice, pale stool, fatigue and upper abdominal tenderness. After the man quit taking gabapentin, his liver function test and symptoms gradually improved. The case report notes that four unpublished reports of jaundice associated with gabapentin use existed at the time the report was submitted and recommended gabapentin be added to the list of drugs that may lead to the liver condition called cholestasis in which bile flow from your liver becomes blocked.
Drugs.com advises you to tell your doctor if you have a liver condition before taking gabapentin because you may need special tests or a dose adjustment to safely take this drug. Likewise, you need to advise your doctor if you have a kidney ailment or heart disease.
Gabapentin’s common side effects include gastrointestinal upset, sleepiness, dizziness, fatigue, clumsiness, vision changes, back pain, constipation or diarrhea, dry mouth and weight gain. Other possible side effects require immediate medical attention. These include a severe allergic reaction, abnormal thoughts, behavioral problems, back and forth eye movements, chest pain, an irregular heartbeat, sore throat, fever, chills, panic attacks, hyperactivity, memory loss, loss of coordination, mood changes, impulsiveness, hostility, an exaggerated feeling of well-being, new or worsening seizures, weakness or numbness, a severe headache, shortness of breath, twitching, trouble concentrating and swelling of your hands, feet or legs.
REFERENCES & RESOURCES
- Pfizer.com; Neurontin (Gabapentin); July 2010
- MayoClinic.com; Postherpetic neuralgia; May 28, 2010
- MayoClinic.com; Postherpetic Neuralgia Treatments and Drugs; May 28, 2010
- "American Family Physician"; Newer Antiepileptic Drugs; William J. Curry, M.D, et al.; Feb. 1998
- Drugs.com: Gabapentin Side Effects
- “BMJ”; Gabapentin Induced Cholestasis; Charles E Richardson; 2002
- Drugs.com: Gabapentin
- PubMed Health; Cholestasis; May 23, 2010
- Merck Manuals Online Medical Library; Cholestasis; Aug. 2006