Propranolol's duration and how long it lasts in the body depend on the formulation and dosage:
- Immediate-release propranolol typically starts working within 1 to 2 hours after taking it, with peak effects around 1 to 4 hours. Its therapeutic effects generally last about 8 to 12 hours. The drug has a half-life of about 3 to 6 hours, meaning half of the drug is eliminated from the body in this time. It usually takes about 15 to 30 hours (around 5 half-lives) for propranolol to be fully cleared from the system after the last dose
- Extended-release propranolol takes longer to reach peak blood levels (around 6 hours) but its effects can last up to 24 hours. The half-life of extended-release propranolol is longer, about 8 to 10 hours, allowing once-daily dosing for some patients
- After stopping propranolol, it can take 1 to 2 days for the drug to clear from the body, but full elimination may take up to 5 days, especially with long-term use. Abruptly stopping propranolol can cause rebound symptoms, so tapering under medical supervision is recommended
In summary, immediate-release propranolol effects last roughly 8 to 12 hours, while extended-release formulations can last up to 24 hours. The drug is eliminated from the body within 1 to 2 days, but full clearance may take longer depending on use and individual factors
