Spironolactone may cause headache, drowsiness, and gastrointestinal disturbances such as cramps and diarrhea. Other reported effects include ataxia, confusion, and skin rashes. Gynecomastia is relatively common and may persist in rare cases. Endocrine-related effects may include hirsutism, deepened voice, menstrual irregularities, and impotence. Temporary increases in blood urea nitrogen (BUN) and mild acidosis may occur. Spironolactone may also lead to hyponatremia and hyperkalemia. Excessive diuresis can result in dehydration, reduced blood volume, circulatory collapse, and an increased risk of thrombosis or embolism, especially in elderly patients. Severe depletion of potassium and magnesium may cause cardiac arrhythmias.