Gabapentin
Sold as Neurontin
Gabapentin is used for nerve pain (postherpetic neuralgia, diabetic neuropathy) and as an add-on for partial seizures.
Boxed warning
FDA Drug Safety Communication (December 2019): serious breathing difficulty (respiratory depression), including deaths, has occurred when gabapentin or pregabalin is combined with opioids, benzodiazepines, or other CNS depressants — and in patients with existing respiratory risk factors (e.g. COPD, older age). Gabapentinoids are not FDA-classified with a formal boxed warning in the label the way black-box drugs are, but the FDA safety communication is being surfaced here with equal visibility because of the seriousness of the risk. Tell your prescriber about every opioid, benzodiazepine, sleep aid, or muscle relaxant you take.
What it treats
Neuropathic pain, partial seizures, restless legs syndrome (off-label).
Typical dosing
Titrated from 300 mg/day up to 1800–3600 mg/day in divided doses (dose depends on indication and response). Dose MUST be reduced with impaired kidney function — gabapentin is cleared almost entirely by the kidneys: • CrCl ≥60 mL/min: standard dosing (up to 3600 mg/day in 3 divided doses). • CrCl 30–59 mL/min: reduce total daily dose by about 50% (e.g. 400–1400 mg/day in 2 divided doses). • CrCl 15–29 mL/min: reduce further, about 25% of standard (e.g. 200–700 mg/day, once daily). • CrCl <15 mL/min: 100–300 mg once daily. • Hemodialysis: use a reduced maintenance dose based on CrCl, PLUS a supplemental dose after each dialysis session (dialysis removes gabapentin). Always confirm the exact dose with your prescriber/pharmacist using your current renal function.
Monitoring
Kidney function (CrCl/eGFR) before starting and periodically, since dosing depends on it. Watch for signs of respiratory depression (excess sedation, slow/shallow breathing) especially when combined with opioids or benzodiazepines.
Side effects
Drowsiness, dizziness, peripheral edema, weight gain, fatigue, coordination problems. Serious: respiratory depression (see warning above), suicidal thoughts (small increased risk across anticonvulsants), severe allergic reaction (DRESS syndrome — rash, fever, swollen lymph nodes).
Interactions to know
Antacids reduce absorption — separate by 2 hours. Additive sedation and respiratory depression risk with opioids, benzodiazepines, alcohol, and other CNS depressants — this combination requires caution and, often, dose adjustment or closer monitoring per your prescriber.
Pregnancy & breastfeeding
Limited data — discuss with prescriber.
Clinical content reviewed by the BetterBuyRx clinical team, on 2026-07-07.
Educational only. Not medical advice. Always confirm with your prescriber or pharmacist.