In this drug factsheet:
What side effects are possible with this medication?
Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.
The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.
The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.
Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.
- flushing and feeling of warmth
- unusual tiredness or weakness
Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.
Check with your doctor as soon as possible if any of the following side effects occur:
- bleeding, tender, or swollen gums
- breathing difficulty, coughing, or wheezing
- chest pain (may appear about 30 minutes after taking medication)
- dizziness, lightheadedness, or fainting
- irregular or fast, pounding heartbeat
- muscle weakness
- skin rash
- slow heart rate (less than 50 beats per minute)
- swelling of ankles, feet, or lower legs
- unusual secretion of milk
Stop taking the medication and seek immediate medical attention if any of the following occur:
- symptoms of a serious allergic reaction, e.g.
- difficulty breathing
- swelling of the face or throat
Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.
Are there any other precautions or warnings for this medication?
Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.
Low blood pressure and heart rate: Low blood pressure symptoms of tiredness and weakness with faintness have been reported following single doses and even after some months of treatment with verapamil. Some people may require a reduced dose. Verapamil can cause very low heart rate for some people. Report an abnormally low heart rate (less than 50 beats per minute) to your doctor.
Medical conditions: If you have kidney disease, liver disease or a neuromuscular disease (such as myasthenia gravis, Lambert-Eaton syndrome, or Duchenne muscular dystrophy), discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.
Pregnancy: This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.
Breast-feeding: This medication passes into breast milk. If you are a breast-feeding mother and are taking verapamil, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.
Children: The safety and effectiveness of using this medication have not been established for children.
Seniors: Seniors may have a higher risk of side effects with this medication.
What other drugs could interact with this medication?
There may be an interaction between verapamil and any of the following:
- "azole" antifungals (e.g., ketoconazole, fluconazole)
- benzodiazepines (e.g., diazepam, lorazepam)
- beta-blockers (e.g., propranolol, metoprolol)
- cancer medications
- calcium salts (e.g., calcium carbonate, calcium gluconate)
- certain medications that affect your immune system (e.g., cyclosporine, sirolimus, tacrolimus, everolimus)
- grapefruit juice
- neuromuscular blocking agents (e.g., atracurium, pancuronium)
- non-steroidal anti-inflammatory medications (NSAIDS; e.g., ibuprofen, naproxen)
- other medications that lower blood pressure (e.g., hydrochlorothiazide)
- other medications that treat abnormal heart rhythms (e.g., disopyramide, flecainide, propafenone, quinidine)
- St. John's wort
- "statin" medications (e.g., atorvastatin, lovastatin, simvastatin)
- tricyclic antidepressants (e.g., amitriptyline, desipramine imipramine)
If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:
- stop taking one of the medications,
- change one of the medications to another,
- change how you are taking one or both of the medications, or
- leave everything as is.
An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.
Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.