Bupranolol is quickly and completely absorbed from the gut. Over 90% undergo first-pass metabolism. Bupranolol has a plasma half life of about two to four hours, with levels never reaching 1 μg/L in therapeuticdoses. The main metabolite is carboxybupranolol, 4-chloro-3-benzoic acid - that is, the methyl group at the benzene ring is oxidized to a carboxyl group - of which 88% are eliminated renally within 24 hours.