What is a common adverse effect of cotrimoxazole?

Cotrimoxazole, a combination of sulfamethoxazole and trimethoprim, is commonly associated with hyperkalemia as an adverse effect. This medication can lead to an increased level of potassium in the blood due to its effects on renal handling of potassium. The trimethoprim component can act as a potassium-sparing diuretic, which may result in elevated serum potassium concentrations, particularly in patients with underlying renal impairment or those taking other medications that affect potassium levels.

Understanding how cotrimoxazole works and its mechanism of action helps clarify why hyperkalemia may occur, especially when monitoring patients who are at a higher risk.

The other options listed represent adverse effects associated with different medications or classes of drugs. For example, pulmonary fibrosis is more commonly linked to medications such as nitrofurantoin or certain chemotherapeutic agents. Tendon rupture is generally associated with fluoroquinolones. Blood glucose disturbances can arise from a variety of medications, particularly corticosteroids or certain antihypertensives, but are not characteristic of cotrimoxazole.

Therefore, recognizing hyperkalemia as a common adverse effect of cotrimoxazole is crucial for ensuring patient safety and proper management, especially in populations that may be more