Effect of kolanut on the pharmacokinetics of the antimalarial drug halofantrine

Abstract

Co-administration of halofantrine and kolanut caused a significant decrease in the plasma concentrations of halofantrine and the active metabolite desbutylhalofantrine probably during adsorption of the drug due to complex formation. This indicates that caution should be exerted when the drug is taken together with caffeine-containing nutrients.

Effect of dehusked Garcinia kola seeds on the overall pharmacokinetics of quinine in healthy Nigerian volunteers

“…There are several reports of other commonly consumed supplements with significant effects on drug bioavailability and disposition. For example, kola nut has been reported to cause a significant decrease in the plasma concentration of halofantrine and its metabolite when co‐administered and Tamarindus indica the major component of a local drink widely taken in the Northern part of Nigeria has been reported to significantly decrease the bioavailability of aspirin in healthy human subjects …”

“…35 There are several reports of other commonly consumed supplements with significant effects on drug bioavailability and disposition. For example, kola nut has been reported to cause a significant decrease in the plasma concentration of halofantrine and its metabolite when coadministered 28 and Tamarindus indica the major component of a local drink widely taken in the Northern part of Nigeria has been reported to significantly decrease the bioavailability of aspirin in healthy human subjects. 38 Although, the exact mechanism responsible for the delayed and decreased absorption of quinine in the presence of G. kola in this current study is not known, it is possible that quinine may have interacted through complex formation with the trace metals or flavonoids usually found in G. kola 6,11 as evidenced from a significant reduction in the C max and t max of quinine but no significant change in parameters which are indicative of interference with elimination.…”

“…The choice of ingesting kola twice daily was to evaluate if a higher dose of G. kola ingestion is associated with further changes on quinine kinetics. Doses of G. kola in this study were chosen based on the consumption pattern from a survey conducted prior to this present study and reports from doses employed in previous studies, both in rats and in man . Prolonged administration of G. kola ensured that a possible induction of enzyme activity by G. kola could be evaluated as it is known that enzyme inhibition may occur with the first dose of the inhibitor, whereas an inducer can cause an increase in enzyme activity over time usually at a relatively higher dose of the inducing agent .…”

“…Doses of G. kola in this study were chosen based on the consumption pattern from a survey conducted prior to this present study and reports from doses employed in previous studies, both in rats and in man. 9,27,28 Prolonged administration of G. kola ensured that a possible induction of enzyme activity by G. kola could be evaluated as it is known that enzyme inhibition may occur with the first dose of the inhibitor, 29,30 whereas an inducer can cause an increase in enzyme activity over time usually at a relatively higher dose of the inducing agent. 31 During the seventh day of bitter kola administration, coinciding with the end of the wash out period, each participant after an overnight fast received bitter kola concomitantly with the administration of a single oral dose of 600 mg quinine sulfate tablets.…”

Effect of fluconazole on the pharmacokinetics of halofantrine in healthy volunteers

“…The blood samples were centrifuged immediately for 15 min at 2000 g and the plasma was transferred into plain tubes and stored at −20 °C until analysed. Plasma samples were assayed for halofantrine and N ‐desbutylhalofantrine by HPLC upon liquid–liquid extraction using a validated method developed earlier (15). The method had a recovery of the compounds of greater than 85%.…”