Hydroxyzine typically starts working within 15 to 60 minutes and reaches its peak effect in about 2 hours. The sedative and therapeutic effects usually last around 4 to 6 hours per dose
. The half-life of hydroxyzine ranges approximately from 14 to 25 hours, with an average around 20 hours in adults. This means it takes about 5 half-lives, or roughly 70 to 125 hours (3 to 5 days), for hydroxyzine to be fully eliminated from the body after the last dose
. While the drug's clinical effects wear off within several hours, hydroxyzine can remain in the system and potentially cause side effects like drowsiness for much longer, especially with regular dosing. Factors such as age, kidney or liver function, dosage, and metabolism can influence how long hydroxyzine lasts and stays in the body
. Summary:
- Onset: 15 to 60 minutes
- Peak effect: ~2 hours
- Duration of effects: 4 to 6 hours
- Half-life: 14 to 25 hours (average ~20 hours)
- Time to clear from system: 70 to 125 hours (3 to 5 days)
If effects persist beyond this or you experience prolonged drowsiness, consult a healthcare provider as it may indicate slower metabolism or drug interactions
