ACE inhibitors can sometimes cause a reversible decrease in kidney function. Your doctor may periodically check your kidney function by either blood or urine tests while you are on the medication. If you notice your feet or ankles swelling or weight gain, notify your doctor. Low blood pressure could lead to severe dizziness or even fainting. Consult your physician if any of these conditions occurs.
ACE inhibitors can occasionally cause the body to retain too much potassium.
Rarely, potassium excess in the body can cause confusion, irregular heartbeat, weakness in the legs, nervousness, or tingling in the hands, feet or lips. If any of these occurs, contact your doctor immediately. Also, consult your doctor before using any salt substitutes, since many of these contain potassium. Diabetic patients who test their urine for acetone should be aware that captopril can cause a false-positive reading. Animal studies show ACE inhibitors may cause problems during pregnancy.