Modification of propranolol's bioavailability by Eurycoma longifolia water-based extract.

Area of Science:

• Pharmacology
• Pharmacokinetics
• Herbal Medicine Interactions

Background:

• Eurycoma longifolia (E. longifolia) is a herb used for aphrodisiac properties, often by Asian males, including those with hypertension on propranolol.
• Propranolol, a beta-blocker, can cause sexual dysfunction as a side effect.
• No prior studies have investigated the pharmacokinetic interaction between E. longifolia and propranolol.

Purpose of the Study:

• To investigate the pharmacokinetic effects of Eurycoma longifolia on propranolol in healthy male volunteers.
• To compare propranolol's pharmacokinetics when administered with E. longifolia versus a placebo.

Main Methods:

• A placebo-controlled, randomized, single-blinded, crossover study involving 14 healthy, non-smoking young males.
• Participants received a single oral dose of 80 mg propranolol with either a placebo or 200 mg of a water-based E. longifolia extract.
• Plasma concentrations of propranolol were measured over 10 hours using high-performance liquid chromatography (HPLC).

Main Results:

• Co-administration with E. longifolia decreased propranolol's bioavailability (AUC0-∞) by 29%.
• Maximum plasma concentration (Cmax) of propranolol was reduced by 42%, and the time to reach Cmax (Tmax) was significantly prolonged by 86%.
• The terminal elimination half-life of propranolol was not significantly affected.

Conclusions:

• Eurycoma longifolia significantly reduces propranolol bioavailability, primarily by decreasing its absorption.
• The interaction does not appear to be mediated by increased propranolol metabolism.
• While pharmacodynamics were unaffected in healthy volunteers, caution is recommended when co-administering E. longifolia and propranolol.