Hypetor Mechanism of Action

Pharmacology: Pharmacokinetics: Metoprolol is readily and completely absorbed from the gastro-intestinal tract but is subject to considerable first-pass metabolism. Peak plasma concentrations occur about 1.5 hours after a single oral dose. Peak plasma-metoprolol concentrations at steady state with usual doses have been reported as 20 to 340 ng per mL. It is moderately lipid-soluble. Metoprolol is widely distributed, it crosses the blood-brain barrier, the placenta, and is distributed in breast milk. It is slightly bound to plasma protein, it is extensively metabolized in the liver by oxidative deamination-O-dealkylation followed by oxidation and aliphatic hydroxylation. The metabolites are excreted in the urine together with only small amounts of unchanged metoprolol.
The rate of hydroxylation to alpha-hydroxymetoprolol is reported to be determined by genetic polymorphism; the half-life of metoprolol in fast hydroxylators is stated to be 3-4 hours, whereas in poor hydroxylators it is about 7 hours. Metoprolol is removed by dialysis.