Atovaquone

Trade Names:Mepron- Suspension 750 mg/5 mL

Pharmacology

Inhibits mitochondrial electron transport in metabolic enzymes of microorganisms. This may cause inhibition of nucleic acid and adenosine triphosphate synthesis.

Pharmacokinetics

Absorption

Bioavailability is approximately 47%. Food increases absorption approximately 2-fold. AUC is approximately 280 h•mcg/mL (fed) and approximately 169 h•mcg/mL (fasting). C _max is approximately 15.1 mcg/mL (fed) and 8.8 mcg/mL (fasting).

Distribution

Highly lipophilic. May undergo enterohepatic recycling. Vd is 0.6 L/kg. 99.9% protein bound.

Elimination

T _1/2 is 67 to 77.6 h. More than 94% is excreted unchanged in the feces; less than 0.6% is excreted in the urine.

Indications and Usage

Treatment of mild to moderate Pneumocystis carinii pneumonia (PCP) in patients who are intolerant of trimethoprim-sulfamethoxazole and acute oral treatment of mild to moderate PCP in patients who are intolerant to trimethoprim-sulfamethoxazole.

Contraindications

Standard considerations.

Dosage and Administration

PO 1,500 mg once daily with a meal.

PO 750 mg administered with food twice daily for 21 days (total daily dose, 1500 mg).

Storage/Stability

Do not freeze.

Drug Interactions

Food, particularly fats, increases absorption 3-fold.

Atovaquone is highly protein bound; interactions may occur because of competition for binding sites.

Decreases steady-state plasma concentrations of atovaquone and increases steady-state plasma concentrations of rifampin.

Laboratory Test Interactions

None well documented.

Adverse Reactions

CNS

Headache; insomnia; dizziness; anxiety.

Dermatologic

Rash; pruritus.

EENT

Sinusitis; rhinitis; altered taste.

GI

Nausea; diarrhea; vomiting; abdominal pain; constipation; oral monilia; anorexia; dyspepsia.

Genitourinary

Elevated creatinine; elevated BUN.

Hematologic

Anemia; neutropenia.

Hepatic

Elevated liver enzymes.

Respiratory

Increased cough.

Miscellaneous

Fever; sweating; weakness; decreased sodium concentration; elevated amylase; allergic reaction; rhinitis; asthenia; infection; dyspnea.

Precautions

Pregnancy

Category C .

Lactation

Undetermined.

Children

Safety and efficacy not established.

Elderly

Atovaquone has not been systematically evaluated in patients older than 65 yr of age.

Hepatic Function

Use caution and closely monitor administration.

Severe PCP

Treatment of severe episodes of PCP has not been evaluated. Efficacy in patients not responding to trimethoprim-sulfamethoxazole has not been established. Atovaquone has not been evaluated for prophylaxis of PCP.

Patient Information

• Inform patient that medication is most effective when taken with food (particularly fatty foods), and to notify health care provider if unable to eat.
• Inform patient that slight rash may develop while taking medication.
• Teach patient to recognize signs of oral fungal infections.

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