in vivo
Cyclizine is metabolized to its N-desmethyl derivative, Norcyclizine, which has little antihistamine (H1) activity compared to Cyclizine. After oral administration of Cyclizine, the effect will be produced within 30 minutes, and the maximum effect will be achieved within 1-2 hours, which can last for 4-6 hours. Cyclizine administered orally at a dose of 50 mg alone in healthy adult volunteers produced peak plasma concentrations of approximately 70 ng/mL two hours after dosing. The plasma elimination half-life is about 20 hours.
