[Cotrimoxazole in bone-related infections: toxicity and clinical and economic impact].

BACKGROUND: Cotrimoxazole is a therapeutic option for bone-related infections but is associated to hyperkalemia and renal failure. Tolerance to this drug may reduce length of stay (LOS) and hospital charges. AIMS: To evaluate renal, potassium toxicity, clinical outcome, and use of hospital resources in patients treated with cotrimoxazole for bone-related infections.
METHODS: Retrospective analysis of adult patients with bone-related infections confirmed by culture and treated with this drug. Serum potassium and creatinine levels were analyzed during follow-up and risk factors for hyperkalemia were searched. Length of stay (LOS) and hospital charges were compared. Clinical outcome was evaluated as a secondary endpoint.
RESULTS: From 2011 to 2014, 23 patients were identified (mean age 64.7 years). Diabetes mellitus, peripheral vascular disease, and previous amputations prevalence were high (82.6%, 47.8%, and 43.5%, respectively). Median serum potassium concentration increased significantly at first control (4.35 mEq/L to 4.9 mEq/L; p < 0.001), and also creatinine serum concentration (0.9 to 1.1 mg/dL; p < 0.05). Seven patients developed hyperkalemia. Cotrimoxazole was discontinued in 10 patients (43.5%), and in 6, discharge was postponed. Drugs active against the renin-angiotensin system (DAARAS) were associated with kyperkalemia (OR 10.8 IC95 1.37-85; p < 0.05). LOS was higher among patients with cotrimoxazole toxicity (median LOS 56 versus 30 days, p < 0.05). Patients with no cotrimoxazole interruption had less drug-related hospital charges (median values of 563 versus 2820 USD, respectively; p < 0.01).
CONCLUSIONS: Cotrimoxazole use must be monitored in order to detect hyperkalemia or renal toxicity and suspend its prescription. Patients that use DAARAS have a higher risk of kyperkalemia. LOS and drug-related hospital charges are reduced when patients can tolerate cotrimoxazole.