Treatment of Epilepsy. The recommended initial dosage of Gabapentin (Neurontin) for adults being treated for epilepsy is 300 mg taken once up to three times a day. The usual maintenance dose is 900 mg per day given in 3 divided doses.If necessary, the maintenance dose may be increased up to the maximum daily dose of 1,800 mg, until the condition is under control. Children (aged 3 to 12 years old) should be given individualized dosage of gabapentin based on child’s body weight.The recommended initial dose ranges from 10-15 mg/kg/day given in three divided doses, then titrated until the effective dose is reached.f necessary, the maintenance dose may be increased up to the maximum daily dose of 1,800 mg, until the condition is under control. Children (aged 3 to 12 years old) should be given individualized dosage of gabapentin based on child’s body weight.