MEDWATCH:  Truvada® (Emtricitabine and Tenofovir DF) By  Stuart Katsh, MS, RD

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Drug, Food, and Herb Interactions
 

• When Truvada® is administered with didanosine, the Cmax (the highest plasma concentration of a drug between doses) and area under the concentration-time curve (AUC- plasma concentration of a drug, usually over a 24 hour period; average amount of medication that is consistently available) of didanosine increases significantly. Current recommendations are to decrease the dose of didanosine to 250 mg in all patients weighing more than 60 kilograms (kg). There are no dosing recommendations for patients weighing less than 60 kg.

• Atazanavir and lopinavir/ritonavir have been shown to increase Tenofovir DF concentrations. No dosage adjustments have been recommended.

• Truvada® decreases the AUC and Cmin (lowest plasma concentration of a drug) of atazanavir. It is recommended to co-administer atazanavir (300 mg) with ritonavir (100 mg) when combined with Truvada®.

• Careful monitoring is recommended when Truvada® is given with other medications known to have renal and/or hepatic toxicity.

• Interactions between Truvada® and specific herbs are unknown but people should avoid using any herbs known to interact with HIV medications. Herbs with known precautions should be avoided as well. This may include St. John's Wort, Silymarin (Milk Thistle), garlic, and others.