Atovaquone

INTRODUCTION

Indications

Treatment of mild-to-moderate Pneumocystis carinii pneumonia (PCP) in patients who are unable to tolerate trimethoprim-sulfamethoxazole. Prophylaxis of PCP.

Action

Inhibits the action of enzymes necessary to nucleic acid and ATP synthesis in protozoa. Therapeutic Effects: Antiprotozoal action against P. carinii.

Adverse Reactions/Side Effects

CNS: headache, insomnia. Resp: cough. GI: diarrhea, nausea, vomiting. Derm: rash. Misc: fever.

PHYSICAL THERAPY IMPLICATIONS

Examination and Evaluation

• Assess pulmonary function by measuring lung volumes, breath sounds, respiratory rate, and other symptoms (cough, dyspnea, shortness of breath) (See Appendices I, J, K). Report changes in pulmonary function to help document the effects of drug therapy in treating PCP infections.

Interventions

• Implement therapeutic exercises and airway clearance techniques as needed to maintain and improve pulmonary function in patients with respiratory infections.

Patient/Client-Related Instruction

• Remind patient to take this drug as directed for the full course of treatment even if feeling better.

• Instruct patient and family/caregivers to report other troublesome side effects such as severe or prolonged headache, sleep loss, skin rash, fever, or GI problems (diarrhea, nausea, vomiting).

Pharmacokinetics

Absorption: Absorption is poor but is increased by food, particularly fat.

Distribution: Enters CSF in very low concentrations (<1% of plasma levels).

Protein Binding: >99.9%.

Metabolism and Excretion: Undergoes enterohepatic recycling; elimination occurs in feces.

Half-life: 2.2–2.9 days.

Contraindications/Precautions

Contraindicated in: Hypersensitivity; Lactation: May appear in breast milk.

Use Cautiously in: Decreased hepatic, renal, or cardiac function (dosage modification may be necessary); GI disorders (absorption may be limited); OB: Safety not established; Pedi: Safety not established.

Interactions

Drug-Drug: May interact with drugs that are highly bound to plasma proteins (does not appear to interact with phenytoin).

Drug-Food: Food enhances absorption.

Route/Dosage

Treatment

PO (Adults): 750 mg twice daily for 21 days.

PO (Children): 40 mg/kg/day (unlabeled).

Prevention

PO (Adults and Adolescents 13–16 yr): 1500 mg once daily.

Availability

Suspension: 750 mg/5 mL.