Indinavir Milk thistle

Piscitelli SC, Formentini E, Burstein AH, Alfaro R, Jagannatha S, Falloon J. Effect of milk thistle on the pharmacokinetics of indinavir in healthy volunteers. Pharmacotherapy 2002 22 551-556. 

DiCenzo R, Shelton M, Jordan K, et al. Coadministration of milk thistle and indinavir in healthy subjects. Pharmacotherapy 2003 23 866-870. 

The pharmacokinetics of indinavir 800 mg 8-hourly have been studied in the presence and absence of milk thistle 175 mg (containing silymarin 153 mg) tds for 3 weeks in an open study in 10 healthy volnnteers milk thistle had no significant effect except a small reduction in C in ss (47). 

Although some studies have found that milk thistle slightly lowers indinavir levels, it appears that this is a time-dependent effect rather than a drug interaction, since it also occurred in a control group in one study. The balance of evidence suggests that no important pharmacokinetic interaction occurs. 

Based on animal data, milk thistle might be expected to increase indinavir levels by inhibiting its metabolism, or to have effects via P-glycoprotein. ... 

The currently available data suggest that milk thistle extract does not have an effect on the pharmacokinetics of indinavir, although it is not totally conclusive. The reduction in indinavir levels appears to be just a time-de-pendent effect rather than an effect of the milk thistle, and further study is needed with longer exposure to indinavir than just four doses. 

Mills E, Wilson K, Clarke Foster B, Walker S, Rachlis B, DeGrootN, Montori VM, Gold W, Phillips E, Myers S, GallicanoK. Milk thistle and indinavir a randomized conlrolled pharmacokinetics study andmeta-anafysis. EurJ Clin Pharmacol (2005) 61,1-7. 

Human studies have indicated no interactions between milk thistle and indinavir (DiCenzo et al. 2003 Mills et al. 2005 Piscitelli et al. 2002), digoxin (Gurley et al. 2006b), or irinotecan (van Erp et al. 2005). 

No interaction between indinavir and milk thistle was observed in healthy volunteers orally administered four 800 mg doses of indinavir before or after oral administration of 525 mg milk thistle (containing 459 mg silymarin) daily for 21 days (Piscitelli et al. 2002) or before or after oral administration of 1350 mg milk thistle daily for 30 days (Mills et al. 2005). 

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