- Objective: High-dose loading with oral and intravenous valproate has been reported to be therapeutic in mania over 48 to 72 hours. We hypothesized that very high dose intravenous (IV) valproate might have even more rapid effects equivalent to effects in status epilepticus that occur within 20 minutes. Method: Seven patients with mania (Young Mania Rating Scale score > 20) and minimal prior drug treatment were given valproate 20 mg/kg IV over 30 minutes. Results: No antimanic effects were observed during 120 minutes of observation. There were no side effects. Conclusion: Slowly evolving biochemical changes, perhaps at the gene level, may be required for the antimanic effect of anticonvulsants.