Adverse Reactions to Spironolactone

Of 13,349 hospitalized medical patients monitored in a drug surveillance program, 788 (5.9%) received spironolactone during one or more admissions. Adverse reactions were attributed to spironolactone in 164 patients (20.8%). Hyperkalemia was reported in 68 patients (8.6%). Frequency increased with the level of blood urea nitrogen (BUN) and reached 20.3% in patients with BUN values of 50 mg/100 ml or greater. Hyperkalemia was far more common in patients who received potassium chloride concurrently (15.8%) than in those who did not (5.7%). Of patients with BUN values of 50 mg/100 ml or greater who received potassium chloride, 42.1% became hyperkalemic. Other adverse reactions were less common; dehydration (3.4%), hyponatremia (2.4%), gastrointestinal symptoms (2.3%), neurological disturbances (2.0%), and skin rashes (0.5%). The frequency of these events was not related to BUN levels.