Common side effects of spironolactone include increased urination, headache, fatigue, dizziness, menstrual irregularities, breast tenderness, nausea, vomiting, stomach pain and rash. Serious side effects may include irregular heart rate, little/no urination, and muscle pain/weakness. Allergic reaction to this medication is rare. Symptoms of an allergic reaction include rash, itching/swelling (especially of face/tongue/throat), dizziness and trouble breathing. Spironolactone can cause severe birth defects. This medication should not be used by women who are pregnant, may become pregnant, or are at a high risk of pregnancy.
This is not a complete list of side effects and others may occur. Contact your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.