Get emergency medical help if you have any of these signs of an allergic reaction to verapamil: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
Call your doctor at once if you have:
fast, slow, or irregular heartbeats;
shortness of breath (even with mild exertion), swelling, rapid weight gain;
a light-headed feeling, like you might pass out;
anxiety, sweating, pale skin, wheezing, gasping for breath, cough with foamy mucus, chest pain;
flu symptoms (fever, chills, body aches, vomiting, diarrhea); or
feeling like you might pass out.
Common verapamil side effects may include:
constipation;
headache;
dizziness; or
stuffy nose, sinus pain, sore throat.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.