Pharmacology: Pharmacokinetics: Tamsulosin is absorbed from the gastrointestinal tract and is almost completely bioavailable. The extent and rate of absorption ore reduced by food. After oral doses of an immediate-release preparation, peak plasma concentrations occur after 1 hour. Tamsulosin is about 99% bound to plasma proteins. It is metabolized slowly in the liver primarily by the cytochrome P450 isoenzymes CYP206 and CYP3A4, it is excreted mainly in the urine as metabolites and some unchanged drug. The plasma elimination half-life has been reported to be between 4 and 5.5 hours.