Focus on Alternative and Complementary Therapies
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Focus Alternat Complement Ther©2005 Pharmaceutical Press
Focus Altern Complement Ther 2004; 9: 32
To determine if ingestion of Silybum marianum (milk thistle) affects the pharmacokinetics of indinavir, the authors conducted a three-period, RCT with 16 healthy participants.
Participants were randomised participants to S. marianum or control. All participants received initial dosing of indinavir and baseline indinavir levels were obtained (AUC0–8) (Phase I). The active group then were given 450 mg S. marianum extract capsules to be taken tid from day 2 to day 30. On days 29 and 30, indinavir dosing and sampling was repeated in both groups as before (Phase II). After a washout period of 7 days, indinavir dosing and sampling were repeated as before (Phase III).
Active group mean AUC0–8 indinavir reduced by –4.4% (90% CI, –27.5 to 26%, P = 0.78) from Phase I to Phase II in the active group and by –17.3% (90% CI, –37.3 to 9%, P = 0.25) in Phase III. Control group mean AUC0–8 reduced by –21.5% (90% CI, –43 to 8%, P = 0.2) from Phase I to Phase II and by a significant further reduction at Phase III of –38.5% (90% CI, –55.3 to –15.3%, P = 0.01) of baseline. Indinavir levels were not reduced significantly in the presence of S. marianum.
The significant decline of AUC0–8 in the control group indicates that factors other than the exposure of interest may affect drug pharmacokinetics. To place our findings in context, S. marianum–indinavir trials were identified through systematic searches of the literature. A meta-analysis of three S. marianum–indinavir trials revealed a non-significant pooled mean difference of 1% (95% CI, 53 to 55%, P = 0.97).
Funded by the Ontario HIV Treatment Network.
