Atovaquone

Atovaquone is used with azithromycin for canine Babesia gibsoni infection and feline cytauxzoonosis. Absorption improves when it is given with a fatty meal.

Group

Hydroxynaphthoquinone antiprotozoal

Mechanism of Action

Inhibition of the protozoal mitochondrial cytochrome bc1 complex impairs electron transport and energy-dependent metabolic pathways.

Dose Rates

Dog

Cat

Indications

• Babesia gibsoni infection in dogs, combined with azithromycin.
• Cytauxzoon felis infection in cats, combined with azithromycin and intensive supportive care.
• Alternative treatment of canine pneumocystosis.

Contraindications

• Avoid during pregnancy unless the clinical need outweighs uncertain fetal risk.
• Do not substitute atovaquone–proguanil tablets without accounting for the second active ingredient.
• Malabsorption or inability to administer with food can compromise exposure and treatment response.
• Prior atovaquone hypersensitivity; severe GI disease can make oral exposure unreliable.

Interactions

• Rifampin can reduce atovaquone exposure.
• Proguanil-containing combinations can increase GI intolerance in dogs.
• Metoclopramide and tetracycline may reduce atovaquone concentrations.

Adverse effects

• GI intolerance, including diarrhea or vomiting.
• Poor treatment response with inadequate absorption or resistant parasites.

Toxicity

Veterinary overdose data are limited. Monitor GI tolerance and clinical or hematologic response; incomplete parasite clearance and relapse remain possible. Monitor serial CBCs during treatment of canine babesiosis. Severe disease may also require monitoring of renal indices, hepatic enzymes and potassium. Clinical improvement alone does not establish elimination of infection.

Preparations