In animal models, signs of acute toxicity include ataxia, labored breathing, ptosis, sedation, hypoactivity, and excitation. However, gabapentin's lethal dose was not identified in mice and rats after receiving single oral doses of 8,000 mg/kg.
Acute, life-threatening toxicity has not been seen in humans with gabapentin overdoses of up to 49 g. In these cases, double vision, slurred speech, drowsiness, lethargy, and diarrhea were observed. All patients recovered with supportive care.
Patients should be monitored closely and given supportive care following gabapentin overdoses. It is not known whether the use of activated charcoal is effective in delaying the absorption of gabapentin. Gabapentin can be removed by hemodialysis but this is not usually required. However, in patients with renal impairment, hemodialysis may be performed.