What is gabapentin used for?

Gabapentin Uses in Clinical Practice

Gabapentin is primarily used to treat neuropathic pain conditions (particularly postherpetic neuralgia and diabetic peripheral neuropathy), as well as adjunctive therapy for partial onset seizures in adults and children 3 years and older with epilepsy. 1

FDA-Approved Indications

• Management of postherpetic neuralgia in adults 1
• Adjunctive therapy for partial onset seizures (with or without secondary generalization) in adults and children 3 years and older with epilepsy 1

Neuropathic Pain Applications

Gabapentin is well-established as a treatment for various neuropathic pain conditions:

Diabetic Peripheral Neuropathy

• Binds to the α-2-δ subunit of calcium channels, reducing calcium influx and decreasing neurotransmitter release in hyperexcited neurons 2
• Provides substantial pain relief (at least 50% reduction) in 38% of patients with painful diabetic neuropathy compared to 21% with placebo 3
• Typical doses range from 1200-3600 mg/day, though clinical practice often uses lower doses than those in clinical trials 2

Postherpetic Neuralgia

• Provides substantial pain relief in 32% of patients compared to 17% with placebo 3
• Recommended as a first-line oral treatment for this condition 2

HIV-Associated Neuropathic Pain

• Recommended as first-line oral pharmacological treatment for chronic HIV-associated neuropathic pain 2
• May reduce HIV-associated sensory neuropathies through central allodynic effects and inhibition of ectopic discharge activity from injured nerves 2

Other Clinical Applications

Erythromelalgia

• Used with varying success in treating erythromelalgia (a rare vascular pain disorder) 2
• All 16 patients in one survey reported improvement with gabapentin, though none experienced complete remission 2

Hot Flashes

• Effective in moderating both severity and duration of hot flashes 2
• In a double-blinded, placebo-controlled study of women with breast cancer, higher-dose gabapentin (900 mg/day) reduced hot flash severity by 46-49% compared to 15-21% with placebo 2

Psychiatric Conditions

• Used in bipolar disorder and other psychiatric conditions, though this is not an FDA-approved indication 4

Dosing Considerations

• Starting dose typically 300 mg on day 1,600 mg on day 2, and 900 mg on day 3 5
• Titration to 1800 mg/day recommended for greater efficacy 5
• Doses up to 3600 mg/day may be needed in some patients 5
• Elderly patients and those with renal impairment require dose adjustments 6

Adverse Effects

Common side effects include:

• Dizziness (19% of patients) 3
• Somnolence (14%) 3
• Peripheral edema (7%) 3
• Gait disturbance (14%) 3

Important Considerations

Discontinuation

• Never stop gabapentin abruptly as this can cause withdrawal symptoms including pruritus, restlessness, confusion, agitation, anxiety, and headache 6, 1
• A gradual taper over weeks to months is recommended for patients on high doses or long-term therapy 6

Drug Interactions

• Fewer drug interactions compared to other antiepileptic medications 7
• If taken with antacids containing aluminum and magnesium, wait at least 2 hours before taking the next dose of gabapentin 1

Special Populations

• Requires dose adjustment in patients with renal impairment 6
• Elderly patients may need lower doses and more gradual titration 6

Clinical Pearls

• Despite being commonly prescribed for chemotherapy-induced peripheral neuropathy, evidence for this use is limited and conflicting 2
• Insurance companies often require trial of gabapentin before allowing use of duloxetine for neuropathic pain, despite guidelines suggesting otherwise 2
• The pharmacokinetic profile of gabapentin limits drug interactions, making it a good choice for patients on multiple medications 7