Concomitant administration of rifampin or rifabutin is known to reduce atovaquone concentrations [see Clinical Pharmacology]. The concomitant administration of MALARONE and rifampin or rifabutin is not recommended.
Proguanil may potentiate the anticoagulant effect of warfarin and other coumarin-based anticoagulants. The mechanism of this potential drug interaction has not been established. Caution is advised when initiating or withdrawing malaria prophylaxis or treatment with MALARONE in patients on continuous treatment with coumarin-based anticoagulants. When these products are administered concomitantly, coagulation tests should be closely monitored.
Concomitant treatment with tetracycline has been associated with a reduction in plasma concentrations of atovaquone [see Clinical Pharmacology]. Parasitemia should be closely monitored in patients receiving tetracycline.
While antiemetics may be indicated for patients receiving MALARONE, metoclopramide may reduce the bioavailability of atovaquone and should be used only if other antiemetics are not available [see Clinical Pharmacology].
Concomitant administration of atovaquone and indinavir did not result in any change in the steady‑state AUC and Cmax of indinavir but resulted in a decrease in the Ctrough of indinavir [see Clinical Pharmacology]. Caution should be exercised when prescribing atovaquone with indinavir due to the decrease in trough concentrations of indinavir.