Medications and Drugs
Pharmacy Author: Omudhome Ogbru, Pharm.D.
Medical Editor: Jay W. Marks, M.D.
GENERIC NAME: gabapentin
BRAND NAME: Neurontin, Gabarone
DRUG CLASS AND MECHANISM: Gabapentin is an anticonvulsant that is used
for preventing seizures and for treating postherpetic neuralgia. The mechanism
of action of gabapentin is not known. Gabapentin structurally resembles the
neurotransmitter gamma aminobutyric acid (GABA). It is possible that this
similarity is related to gabapentin's mechanism of action. In animal models used
for testing the anticonvulsant and analgesic activity of drugs, gabapentin
prevents seizures and reduces pain-related responses. The FDA approved
gabapentin in December 1993.
PRESCRIPTION: Yes
GENERIC AVAILABLE: Yes
PREPARATIONS:
- Capsules: 100, 300, and 400 mg.
- Tablets: 100, 300, 400, 600, and 800 mg.
- Solution: 250 mg/5 ml
STORAGE: Tablets and capsules should be stored between 15-30 C
(59-86 F). Gabapentin solution should be refrigerated between 2-8 C (36-46 F).
PRESCRIBED FOR: Gabapentin is approved for treating seizure disorders
and nerve damage from herpes zoster (shingles, postherpetic neuralgia). There
are many non-approved uses for gabapentin. These include
alcohol withdrawal,
cocaine withdrawal, hiccups, restless leg syndrome, hyperhidrosis,
headaches,
diabetic neuropathy, hot flashes, and fibromyalgia.
DOSING: Gabapentin may be taken with or without food. The recommended
dose for postherpetic neuralgia is 1800 mg daily in 3 divided doses. The initial
dose of 300 mg daily is increased over several days to the recommended daily
dose. Seizures are treated with 900-1800 mg/daily in 3 divided doses. Withdrawal
of treatment should occur slowly over a week.
DRUG INTERACTIONS: Antacids reduce the concentration of gabapentin in
blood. Therefore, gabapentin should be administered 2 hours or more after taking
antacids. Morphine significantly increases blood concentrations of gabapentin
and may increase central nervous system-related adverse events associated with
gabapentin.
PREGNANCY: Safety in pregnancy has not been established.
NURSING MOTHERS: Gabapentin is secreted in human
breast milk. Nursing
mothers should only use gabapentin if the benefits outweigh the unknown risk to
the fetus.
SIDE EFFECTS: Common side effects of gabapentin are dizziness,
somnolence,
ataxia, fatigue, fluid retention, hostility, nausea and
vomiting.
Other adverse events associated with gabapentin include
hypertension, anorexia,
bruising, joint pain, motion sickness, and pneumonia.
Antiepileptic medications have been associated
with increased risk of suicidal thinking and behavior. Anyone
considering the use of antiepileptic drugs must balance this risk of suicide with the clinical need. Patients who are
started on therapy should be closely observed for clinical worsening, suicidal
thoughts, or unusual changes in behavior.
Reference: FDA Prescribing Information
Last Editorial Review: 9/10/2008
Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
- Drug Interactions - Learn about potential drug interactions you may be exposed to. Drug interactions can occur with prescription drugs, OTC medication, vitamins, herbs, and supplements.
- Epilepsy Treatment - Information on Epilepsy treatment includes how epilepsy is treated, drug therapy, side effects, and surgery.
- Shingles - Read about shingles symptoms (contagious rash), vaccine, causes (chickenpox [varicella] virus, stress), treatment, how it's transmitted and postherpetic neuralgia.
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