Antiparasitic / Antifungal — PCP Prophylaxis / Treatment / Malaria Pregnancy: eMC §4.6: there is no information on the effects of atovaquone administration during human pregnancy. Atovaquone should not be used during pregnancy unless the benefit of treatment to the mother outweighs any possible risk to the developing foetus; insufficient animal data are available to assess the possible risk to reproductive potential or performance. Breast-feeding: it is not known whether atovaquone is excreted in human milk, therefore breast-feeding is not recommended. This presentation contains benzyl alcohol - use with caution and only if necessary in pregnant or breast-feeding patients because of the risk of accumulation and toxicity. (US labelling: Pregnancy Category C.)

Atovaquone

Brand names: Wellvone, Malarone (combined with proguanil)

Atovaquone is an oral antiprotozoal and antifungal agent used mainly for the treatment and prevention of Pneumocystis jirovecii pneumonia in patients who cannot tolerate co-trimoxazole, and for toxoplasmosis.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: 750 mg (5 ml of the 750 mg/5 ml oral suspension) twice a day

Route: Oral - must be taken with food

Frequency: Twice a day (morning and evening), with food, each day for 21 days

eMC §4.2 (Atovaquone Glenmark 750 mg/5 ml oral suspension), Pneumocystis pneumonia: 'The recommended oral dose is 750 mg twice a day (1 x 5 ml morning and evening) administered with food each day for 21 days. Higher doses may be more effective in some patients.' FOOD: the SPC stresses the importance of taking the full prescribed dose with food - food, particularly high-fat food, increases bioavailability two- to three-fold. CHILDREN: the UK SPC states 'Dosage in Children: Clinical efficacy has not been studied' - no paediatric dose is given; verify any under-18 use against a children's formulary. OLDER PEOPLE: there have been no studies in the elderly and no clinical experience has been gained in elderly patients - use in the elderly should be closely monitored. Efficacy has NOT been systematically evaluated in patients failing other PCP therapy (including co-trimoxazole), for treatment of severe PCP [(A-a)DO2 greater than 45 mmHg (6 kPa)], as a prophylactic agent for PCP, or versus intravenous pentamidine; no data are available in non-HIV immunocompromised patients with PCP. Diarrhoea at the start of treatment is associated with significantly lower atovaquone plasma levels, which correlated with a higher incidence of therapy failure and lower survival - consider alternative therapy for such patients and for those who have difficulty taking the suspension with food. Patients with pulmonary disease should be carefully evaluated for causes other than PCP. This presentation contains benzyl alcohol (SPC §4.4), which may cause allergic reactions and can accumulate in newborns up to 4 weeks old due to metabolic immaturity (intravenous benzyl alcohol has been associated with 'gasping syndrome' and death in neonates); it should not be used for more than a week in children under 3 years, and should be used with caution and only if necessary in pregnant or breast-feeding patients or in patients with liver or kidney impairment. US labelling (Lupin, DailyMed 2021) additionally gives a PCP PREVENTION regimen of 1,500 mg (10 mL) once daily with food, and the same treatment regimen of 750 mg (5 mL) twice daily with food for 21 days - the UK SPC used here does not carry a prophylaxis indication; verify against the UK SPC and local policy before using for prophylaxis.

Dose adjustments

Renal

eMC §4.2: not specifically studied in patients with significant hepatic or renal impairment. If it is necessary to treat such patients, caution is advised and administration should be closely monitored; no numeric dose adjustment is stated. The benzyl alcohol content means it should be used with caution in liver or kidney impairment because of the risk of accumulation and toxicity (metabolic acidosis). US labelling §5.2: closely monitor patients with severe hepatic impairment following administration - cases of cholestatic hepatitis, elevated liver enzymes and fatal liver failure have been reported.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Known hypersensitivity to atovaquone or to any of the excipients (eMC §4.3)
US labelling additionally: patients who develop or have a history of hypersensitivity reactions (e.g. angioedema, bronchospasm, throat tightness, urticaria) to atovaquone or any component of the oral suspension

Side effects

Very common: nausea
Very common: rash, pruritus
Common: diarrhoea, vomiting
Common: headache, insomnia, fever
Common: anaemia, neutropenia, hyponatraemia
Common: elevated liver enzyme levels; hypersensitivity reactions including angioedema, bronchospasm and throat tightness
Not known: erythema multiforme, Stevens-Johnson syndrome

Interactions

Rifampicin or rifabutin - concomitant administration is NOT recommended (reduces atovaquone concentrations)
Tetracycline - reduces atovaquone concentrations; patients receiving concurrent tetracycline should be closely monitored for loss of atovaquone efficacy
Metoclopramide - concurrent use is not recommended; another antiemetic treatment should be given
Efavirenz or boosted protease inhibitors - concomitant administration should be avoided whenever possible
Etoposide - atovaquone can increase the levels of etoposide and its metabolite
Indinavir (US labelling) - reduces indinavir trough concentrations; use caution and monitor for loss of indinavir efficacy

Clinical monograph

How it works

It selectively inhibits the parasite cytochrome bc1 complex of the mitochondrial electron transport chain, disrupting pyrimidine biosynthesis and energy production.

Prescribing in practice

Absorption is poor and highly dependent on fat, so atovaquone must be taken with a fatty meal to achieve adequate plasma concentrations and treatment efficacy, particularly important in patients with diarrhoea or malabsorption.
It is generally less effective than co-trimoxazole for Pneumocystis pneumonia, so it is reserved for those intolerant of first-line therapy.
Concurrent rifampicin and certain other agents can substantially lower atovaquone levels and reduce efficacy.

Monitoring

Monitor clinical response and tolerability, with attention to whether the drug is being taken with food to ensure adequate absorption.

Counselling the patient

Always take this medicine with food, ideally something containing fat, to help it work.
Continue prophylaxis for as long as advised even when you feel well.
Report persistent diarrhoea or vomiting, which may reduce how well the drug is absorbed.

Evidence & guidelines

Atovaquone is recommended in UK guidance as an alternative agent for Pneumocystis jirovecii pneumonia prophylaxis and treatment in patients intolerant of co-trimoxazole.

Reference: BHIVA HIV Guidelines; PHE Malaria Guidelines; NICE Malaria Prevention Guidance; IDSA PCP Guidelines; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways