Use

Phenobarbital is a general central nervous system suppressant used for therapeutic drug monitoring. It has proven effectiveness in controlling generalized and partial seizures. Therapeutic serum concentrations are typically between 15–40 µg/mL, while toxic concentrations exceed 60 µg/mL. The drug has a long half‑life (~80 hours), so steady‑state levels are reached after approximately two weeks of therapy. Monitoring helps guide dosing to maintain efficacy and avoid toxicity.