If your doctor has prescribed verapamil, it is because they have deemed that the benefit to you is greater than the potential risk of side effects. However, adverse reactions do occasionally occur. Common side effects include constipation, heartburn, dizziness, and headache. Tell your doctor if any of these are severe or don’t go away.
Rare, but serious side effects include fainting, new or worsening symptoms of heart failure (such as swelling of the hands, feet, or ankles; shortness of breath; or unusual weight gain), very slow heartbeat, liver disease/damage (symptoms include excessive vomiting, loss of appetite, abdominal pain, dark urine, or yellowing of the skin/eyes), or allergic reactions (such as rash, itching, swelling of the face/tongue/throat, and difficulty breathing or swallowing). Get immediate medical attention if you experience any of these complications.
Talk to your doctor about your medical history - have or have ever had a narrowing or blockage of your digestive system or any other condition that causes food to move through your digestive system more slowly; heart failure; heart, liver, or kidney disease; muscular dystrophy (a genetic disease that causes gradual weakening of the muscles); or myasthenia gravis (a condition that causes certain muscles to weaken). Inform your doctor of all known allergies and of all medications, supplements, and herbal products that you take. Tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding.
This is not a complete list of side effects or precautions. For more information please visit the National Institutes of Health’s DailyMed webpage for Verapamil.