The magnitude of the effect of garlic will depend upon doses and concentrations of garlic supplementation and the clinical significance of these interactions is difficult to predict.
The effect of garlic supplements on the pharmacokinetics of saquinavir
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Study Design
Pharmacokinetic studies to determine the effect of concomitant garlic and amprenavir levels has not been conducted, but data may be extrapolated from further research using garlic with saquinavir. This study evaluated the effect of garlic supplements on the pharmacokinetics of saquinavir. Ten healthy volunteers received 10 doses of saquinavir (Fortovase) at a dosage of 1200 mg 3 times daily with meals for 4 days on study days 1–4, 22–25, and 36–39, and they received a total of 41 doses of garlic caplets taken 2 times daily on study days 5–25. Blood samples were obtained on study days 4, 25, and 39 for determination of saquinavir plasma pharmacokinetic parameters.
Study Results
In the presence of garlic, the mean saquinavir area under the curve (AUC) during the 8-h dosing interval decreased by 51%, trough levels at 8 h after dosing decreased by 49%, and the mean maximum concentrations (Cmax) decreased by 54%. After the 10-day washout period, the AUC, trough, and Cmax values returned to 60%–70% of their values at baseline.
Study Conclusions
Patients should use caution when combining garlic supplements with saquinavir when it is used as a protease inhibitor. The magnitude of the effect of garlic will depend upon doses and concentrations of garlic supplementation and the clinical significance of these interactions is difficult to predict.
References
Piscitelli SC, Burstein AH, Welden N, Gallicano KD, Falloon J. The effect of garlic supplements on the pharmacokinetics of saquinavir. Clinical Infectious Diseases. 2002; 2: 234-238.
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