Atovaquone

Agents: atovaquone, atovaquone/proguanil

Atovaquone is an antiparasitic agent with activity against several important protozoans. Its activity against the malaria parasite is enhanced when given in combination with the drug proguanil (this co-formulated tablet is known as Malarone). Atovaquone tends to be better tolerated than comparator drugs but is limited by the lack of an IV formulation (for severe disease),  high cost, and somewhat lower efficacy (for Pneumocystis disease).

Spectrum

Like-a-parasite-but-technically-a-fungus: Pneumocystis jirovecii Protozoa: Plasmodium species, Toxoplasma gondii,  Babesia species

Adverse Effects

Both atovaquone and atovaquone/proguanil are very well tolerated. The most common adverse effects are gastrointestinal (nausea/vomiting, diarrhea, abdominal pain).

Important Facts

• Atovaquone is available as a suspension, while atovaquone/proguanil is formulated as a tablet.  Bioavailability is rather low with both, but it is enhanced substantially when given with food, especially high-fat meals. Both agents should be administered with food.

• In clinical trials of atovaquone in treating mild to moderate  Pneumocystis  pneumonia in patients intolerant of TMP/SMX, atovaquone was slightly less effective than its comparators  (dapsone or pentamidine) but better tolerated,  leading to similar overall success rates. Atovaquone should not be used in patients with severe  Pneumocystis  pneumonia or in patients whose GI absorption is thought to be poor.

• Other than its cost, atovaquone/proguanil is a favorable drug for malaria prophylaxis for travelers. It is highly effective, well tolerated,  active against chloroquine-resistant  Plasmodium, and requires administration only 1–2 days prior to travel, while in the malaria-endemic area, and for 7 days after return. Many other agents used for malaria prophylaxis re-quire beginning the medication 2 weeks before travel and continuing for 4 weeks afterward.

What They’re Good For

Atovaquone: Treatment of mild to moderate Pneumocystis pneumonia and prophylaxis against Pneumocystis in patients intolerant of first-line therapy.

Atovaquone/proguanil: Treatment of uncomplicated malaria and prophylaxis against malaria.

Don’t Forget!

Make sure your patients take their atovaquone with food (or at the very least a glass of milk); the bioavailability of atovaquone is increased approximately 5 times when administered with food com-pared with the fasting state.

References

Gallagher ,J.C. and MacDougall ,c. (2012). Antibiotics Simplified. Second Edition. Jones & Bartlett Learning, LLC.