Skip to main content

Drug Interactions between garlic and saquinavir

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

Edit list (add/remove drugs)

Interactions between your drugs

Major

saquinavir garlic

Applies to: saquinavir and garlic

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

Drug and food interactions

Moderate

saquinavir food

Applies to: saquinavir

ADJUST DOSING INTERVAL: Food significantly increases the absorption of saquinavir.

MONITOR: Coadministration with grapefruit juice may increase the plasma concentrations of saquinavir. The primary mechanism is inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall by certain compounds present in grapefruits. In eight healthy volunteers, ingestion of 400 mL of grapefruit juice prior to administration of a 600 mg dose of saquinavir mesylate increased the area under the plasma concentration-time curve and oral bioavailability of saquinavir by 50% and 100%, respectively, compared to water; however, the increase is not considered clinically relevant. A high degree of intersubject variability in the grapefruit juice effect was also observed. The extent to which this interaction may occur with the saquinavir free base soft gelatin capsule is unknown. However, the saquinavir soft gelatin capsule formulation is no longer commercially available.

MANAGEMENT: Saquinavir mesylate should be taken with meals or within 2 hours after eating to enhance bioavailability. Patients should be advised to avoid the consumption of large amounts of grapefruit and grapefruit juice during saquinavir therapy unless otherwise directed by their doctor, as the interaction is unreliable and subject to a high degree of interpatient variation.

References (6)
  1. (2001) "Product Information. Invirase (saquinavir)." Roche Laboratories
  2. Kupferschmidt HHT, Fattinger KE, Ha HR, Follath F, Krahenbuhl S (1998) "Grapefruit juice enhances the bioavailability of the HIV protease inhibitor saquinavir in man." Br J Clin Pharmacol, 45, p. 355-9
  3. Bailey DG, Malcolm J, Arnold O, Spence JD (1998) "Grapefruit juice-drug interactions." Br J Clin Pharmacol, 46, p. 101-10
  4. Eagling VA, Profit L, Back DJ (1999) "Inhibition of the CYP3A4-mediated metabolism and P-glycoprotein-mediated transport of the HIV-I protease inhibitor saquinavir by grapefruit juice components." Br J Clin Pharmacol, 48, p. 543-52
  5. Cerner Multum, Inc. "UK Summary of Product Characteristics."
  6. Cerner Multum, Inc. "Australian Product Information."

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.

See also

Report options

Loading...
QR code containing a link to this page

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.

Medical Disclaimer