A patient with treatment-resistant schizophrenia is being titrated onto clozapine. Above which daily dose does the risk of seizures rise steeply, warranting caution or prophylactic anticonvulsant coverage?

• A Above 150 mg per day
• B Above 300 mg per day
• C Above 1000 mg per day
• D Above 600 mg per day ✓

Explanation

Clozapine lowers the seizure threshold in a dose-dependent manner: seizures occur in roughly 1 to 2 percent below 300 mg per day, around 4 percent between 300 and 600 mg, and above 10 percent beyond 600 mg per day. At higher doses, slow titration, dose reduction, or adjunct valproate is considered. The commonly quoted practical ceiling is 900 mg per day, well below the 1000 mg figure in option C.

Reference: Kaplan and Sadock's Synopsis of Psychiatry, 12th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.