First-pass metabolism of midazolam by the human intestine*

Abstract

The safety, pharmacokinetics, and pharmacodynamics of single oral doses of up to 48 mg and daily (for 28 days) doses of up to 24 mg mofegiline were investigated in healthy male volunteers. Plasma pharmacokinetics indicated rapid absorption and elimination: time to reach maximum concentration occurred at about 1 hour; half‐life ranged from 1 to 3 hours. Maximal plasma concentration and area under the plasma concentration‐time curve increased and oral clearance decreased disproportionately with dose. Mofegiline rapidly and markedly inhibited platelet monoamine oxidase B (MAOB) activity, which returned to baseline within 14 days. Urinary excretion of phenylethylamine increased proportionately with doses up to 24 mg. No changes in urinary elimination of catecholamines, blood pressure, heart rate, or ECG were observed. A classic maximum tolerated dose was not achieved in these studies. However, the 48 mg single dose and the 24 mg multiple daily dose far exceeded the dose (1 mg) that was associated with >90% platelet MAOB inhibition. Clinical Pharmacology & Therapeutics (1995) 58, 342–353; doi: