Pneumocystis jirovecii pneumonia (PJP) is a potentially life-threatening opportunistic infection in immunocompromised individuals. Patients at high risk of PJP (e.g. underlying disease, chemotherapy or immunosuppressive drugs) may require prophylactic therapy. Although trimethoprim-sulfamethoxazole is standard-of-care for PJP prophylaxis, atovaquone is an alternative for patients with sulfonamide allergy or intolerances. Australian guidelines recommend an oral atovaquone dose of 1500mg daily. However, a recent international study investigated a prophylactic 750mg daily dose in lower-risk haematological patients. A local audit of atovaquone dosing practices and subsequent PJP infection was proposed.
A retrospective audit of patients prescribed atovaquone for PJP prophylaxis was conducted at a day oncology outpatient clinic. Ethics approval was obtained.
Dispensing records from 1 January 2020 to 31 December 2024 were reviewed to identify all patients who received atovaquone. Data was collected on dose and duration. Medical records were examined for the duration of administration until the end of the observation period to determine if patients experienced a subsequent PJP infection. Statistical analysis was performed using Microsoft Excel.
All patients who received atovaquone prophylaxis were included (n=88). The median age was 69 years (range 22-89). 50% of patients received low-dose atovaquone (750mg daily) whilst 50% received standard dose (1500mg daily). Treatment duration ranged from 6-261 weeks (750mg daily) and 1-180 weeks (1500mg daily). 91% of patients in the low-dose group were considered low-intermediate risk. No PJP was reported in the low-dose group, however there was one case of PJP in the standard-dose group during the follow-up period.
While no PJP infections were observed in the low-dose group, further study with a larger sample and patient risk stratification is required to establish clinical implication. Consideration of low-dose atovaquone in select patients may reduce financial burden and assist patient compliance and tolerability.