Classification: Antiprotozoal agent
Action/Kinetics: The mechanism of action of atovaquone against Pneumocystis carinii is not known. However, in Plasmodium appears to act by inhibiting electron transport resulting in inhibition of nucleic acid and ATP synthesis. The bioavailability of the drug is increased twofold when taken with food. Plasma levels in AIDS clients are about one-third to one-half the levels achieved in asymptomatic HIV-infected volunteers. t 1/2: 2.2 days in AIDS clients due to enterohepatic cycling and eventually fecal elimination. Not metabolized in the liver; over 94% is excreted unchanged in the feces.
Uses: Acute oral treatment of mild to moderate P. carinii in clients who are intolerant to trimethoprim-sulfamethoxazole. Prophylaxis of P. carinii in clients intolerant to trimethoprim-sulfamethoxazole. Not effective for concurrent pulmonary diseases such as bacterial, viral, or fungal pneumonia or in mycobacterial diseases.
Contraindications: Hypersensitivity to atovaquone or any components of the formulation; potentially life-threatening allergic reactions are possible.
Special Concerns: Use with caution during lactation, in elderly clients, and in severe hepatic impairment. Safety and efficacy have not been determined in children. GI disorders may limit absorption of atovaquone.
Side Effects: Since many clients taking atovaquone have complications of HIV disease, it is often difficult to distinguish side effects caused by atovaquone from symptoms caused by the underlying medical condition. GI: Nausea, diarrhea, vomiting, abdominal pain, constipation, dyspepsia, taste perversion. CNS: Headache, fever, insomnia, dizziness, anxiety, anorexia. Dermatologic: Rash (including maculopapular), pruritus. Respiratory: Cough, sinusitis, rhinitis. Hematologic: Anemia, neutropenia. Miscellaneous: Asthenia, oral monilia, pain, sweating, hypoglycemia, hyperglycemia, hypotension, hyponatremia, allergic reaction, infection.
Laboratory Test Alterations: ALT, AST, alkaline phosphatase, amylase.
Since atovaquone is highly bound to plasma proteins ( >99.9%), caution should be exercised when giving the drug with other highly plasma protein-bound drugs with narrow therapeutic indices as competition for binding may occur.
How Supplied: Suspension: 750 mg/5 mL