MONOPRIL side effects, include nausea, vomiting, or diarrhea; headache; dry cough; dizziness or lightheadedness when sitting up or standing; or fatigue. If MONOPRIL side effects continue or are bothersome, check with your doctor. CHECK WITH YOUR DOCTOR AS SOON AS POSSIBLE if you experience MONOPRIL side effects like shortness of breath, hives, irregular or slow heartbeat, or chest pain. CONTACT YOUR DOCTOR IMMEDIATELY if you experience MONOPRIL side effects like swelling of hands, face, lips, eyes, throat, or tongue; difficulty swallowing or breathing; or hoarseness. If you notice other MONOPRIL side effects not listed above, contact your doctor, nurse, or pharmacist.