title: Tyramine pharmacokinetics and reduced bioavailability with food.
abstract: Tyramine challenge studies have demonstrated that it requires approximately twice the amount of tyramine administered with a meal compared to administration after a fast to elicit the same effect, suggesting a reduction in bioavailability of tyramine when administered with food. The pharmacokinetics of tyramine when administered in a fasted versus a fed state were studied. A single 200-mg dose of tyramine was administered orally to healthy subjects both after an overnight fast and during a meal. Systemic exposure to tyramine was reduced by 53% (p < 0.05), and the maximum concentration of tyramine was reduced by 72% (p < 0.05) when the dose was administered during a meal. Tyramine maximum serum concentration was observed between 20 minutes and 1 hour when the dose was administered after an overnight fast and appeared to be delayed and/or prolonged by administration during a meal. Tyramine oral clearance was 135 +/- 55.4 L/min, maximum observed serum concentration was 37.7 +/- 26.01 ng/mL, and tyramine elimination half-life was 0.533 (range: 0.330-0.668) hours after administration to fasted subjects. Tyramine bioavailability was significantly reduced when administered with a meal compared to after a fast. The results suggest that larger amounts of dietary tyramine will be required to induce a pressor response equivalent to that following encapsulated tyramine administered in the fasted state.
authors.affiliation: Somerset Pharmaceuticals, Inc., Tampa, Florida, USA.
authors.forename: Chad M
authors.initials: CM
authors.lastname: VanDenBerg
authors.forename: Lawrence F
authors.initials: LF
authors.lastname: Blob
authors.forename: Eva M
authors.initials: EM
authors.lastname: Kemper
authors.forename: Albert J
authors.initials: AJ
authors.lastname: Azzaro
mesh_terms: D000328:Adult; D019540:Area Under Curve; D001682:Biological Availability; D005215:Fasting / Q000378:metabolism; D005502:Food; D006207:Half-Life; D006801:Humans; D008297:Male; D008657:Metabolic Clearance Rate; D013566:Sympathomimetics / Q000097:blood / Q000493:pharmacokinetics*; D014439:Tyramine / Q000097:blood / Q000493:pharmacokinetics*
chemical_list: D013566:Sympathomimetics; D014439:Tyramine