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Drug Interactions between garlic and tipranavir

This report displays the potential drug interactions for the following 2 drugs:

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Interactions between your drugs

Major

garlic tipranavir

Applies to: garlic and tipranavir

GENERALLY AVOID: Coadministration with garlic supplements may decrease the plasma concentrations of saquinavir and possibly other protease inhibitors (PIs). The exact mechanism is unknown but may involve induction of CYP450 3A4 metabolism and/or P-gycloprotein transport in the intestine by certain component(s) of garlic. In nine healthy, HIV-negative volunteers, investigators from the National Institutes of Health found that pretreatment with a garlic supplement (GarliPure Maximum Allicin Formula twice daily for 3 weeks) reduced the mean peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) of saquinavir (soft gelatin capsule 1200 mg 3 times daily for 10 doses during the last 4 days of garlic supplementation) by 54% and 51%, respectively, compared to baseline when saquinavir was administered alone. The effects appear to be sustained, since saquinavir Cmax and AUC returned to just 61% and 65% of baseline, respectively, after a 10-day washout period. Whether and how dietary garlic or other formulations of garlic supplement may affect saquinavir pharmacokinetics are currently unknown. It is also uncertain if and to what extent the interaction may occur with other PIs, which are also substrates of CYP450 3A4.

MANAGEMENT: Given the risk of reduced viral susceptibility and resistance development associated with subtherapeutic antiretroviral drug levels, garlic supplements should preferably be avoided in patients treated with PIs, particularly if they are using saquinavir as the sole PI in their antiretroviral regimen. Patients should be advised to consult with their caregivers before using any herbal or alternative medicines.

References

  1. Durant J, Clevenbergh P, Garraffo R, Halfon P, Icard S, DelGiudice P, Montagne N, Schapiro JM, Dellamonica P "Importance of protease inhibitor plasma levels in HIV-infected patients treated with genotypic-guided therapy: pharmacological data from the Viradapt Study." Aids 14 (2000): 1333-9
  2. NIAID. National Institute of Allergy and Infectious Diseases "Garlic supplements can impede HIV medication. http://www.niaid.nih.gov/newsroom/releases/garlic.htm" (2001):
  3. Piscitelli SC, Burstein AH, Welden N, Gallicano KD, Falloon J "The Effect of Garlic Supplements on the Pharmacokinetics of Saquinavir." Clin Infect Dis 34 (2002): 234-238
  4. Borek C "Garlic supplements and saquinavir." Clin Infect Dis 35 (2002): 343
View all 4 references

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Drug and food interactions

Moderate

tipranavir food

Applies to: tipranavir

ADJUST DOSING INTERVAL: Food does not appear to substantially alter the pharmacokinetics of tipranavir. When tipranavir capsules or oral solution was coadministered with ritonavir capsules at steady-state, no clinically significant changes in tipranavir peak plasma concentration (Cmax) and systemic exposure (AUC) were observed under fed conditions (500 to 682 kcal, 23% to 25% calories from fat) relative to fasted conditions. The effect of food on tipranavir exposure during coadministration with ritonavir tablets has not been evaluated. High-fat foods may enhance the gastrointestinal absorption of tipranavir. In a multiple-dose study, administration of tipranavir capsules with a high-fat meal (868 kcal, 53% from fat, 31% from carbohydrates) increased the oral bioavailability of tipranavir by 31% compared to administration with toast and skimmed milk, but did not significantly affect tipranavir Cmax. Thus, tipranavir may be safely taken with standard or high-fat meals.

MANAGEMENT: Tipranavir coadministered with low-dose ritonavir should be taken with food to improve the gastrointestinal tolerability of ritonavir. According to the product labeling, tipranavir coadministered with ritonavir capsules or solution can be taken with or without meals, whereas tipranavir coadministered with ritonavir tablets must be taken with meals.

References

  1. "Product Information. Aptivus (tipranavir)." Boehringer-Ingelheim (2005):
  2. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0
  3. Canadian Pharmacists Association "e-CPS. http://www.pharmacists.ca/function/Subscriptions/ecps.cfm?link=eCPS_quikLink" (2006):
  4. Cerner Multum, Inc. "Australian Product Information." O 0
View all 4 references

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Therapeutic duplication warnings

No warnings were found for your selected drugs.

Therapeutic duplication warnings are only returned when drugs within the same group exceed the recommended therapeutic duplication maximum.

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Drug Interaction Classification

These classifications are only a guideline. The relevance of a particular drug interaction to a specific individual is difficult to determine. Always consult your healthcare provider before starting or stopping any medication.
Major Highly clinically significant. Avoid combinations; the risk of the interaction outweighs the benefit.
Moderate Moderately clinically significant. Usually avoid combinations; use it only under special circumstances.
Minor Minimally clinically significant. Minimize risk; assess risk and consider an alternative drug, take steps to circumvent the interaction risk and/or institute a monitoring plan.
Unknown No interaction information available.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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