Verapamil

What is verapamil?

Verapamil is a prescription-only medication known as a calcium channel blocker. It works by relaxing the muscles of the heart and blood vessels to reduce blood pressure and improve blood flow. It is available under brand names such as Securon, Verapress, and Vera-Til, and comes in tablets, modified-release forms, capsules, and oral solutions[1]. 

What is verapamil used for?

Verapamil is prescribed to treat a range of heart and circulation-related conditions. These include[1]: 

• High blood pressure (hypertension) 

• Prevention of future heart disease, heart attacks, and strokes in people with high blood pressure 

• Chest pain (angina) 

• Abnormal heart rhythms, such as supraventricular tachycardia 

• Cluster headache prevention (occasionally, as an off-label use) 

How does verapamil work?

Verapamil works by blocking calcium from entering the muscle cells of the heart and blood vessels. This leads to[1]: 

• Relaxation of the blood vessels, which helps lower blood pressure 

• Slowing of the heart rate, which helps control abnormal rhythms 

• Reduction in the heart's workload, easing angina symptoms 

Who can take verapamil?

Verapamil is suitable for many adults, but there are some situations where it should be avoided or used with caution. You should speak to a doctor or pharmacist first if you[1]: 

• Have very low blood pressure 

• Have certain heart rhythm disorders (such as second or third-degree AV block) 

• Have untreated heart failure or a very slow or irregular heart rate 

• Are taking ivabradine or intravenous dantrolene 

• Have liver disease, kidney problems, or porphyria 

• Have Wolff-Parkinson-White syndrome (a heart condition) 

• Are pregnant, trying to get pregnant, or breastfeeding, unless advised by a doctor 

Please tell your doctor or pharmacist about any conditions you may have or medication you take before you start treatment, and always follow the instructions in the Patient Information Leaflet[2].  

How do you take verapamil?

Verapamil should be taken exactly as directed[1]: 

• Take with or after food to reduce the risk of stomach upset 

• Swallow tablets whole with water 

• Do not chew or crush modified-release tablets 

• Avoid grapefruit juice, as it can increase the risk of side effects 

What is the typical dosage of verapamil?

The dose depends on the condition being treated and the form of verapamil prescribed: 

• For high blood pressure with standard tablets or liquid: the usual dose is 120mg, taken twice a day, but can be increased to a maximum of 480mg a day, split into 2 or 3 doses 

• For high blood pressure with slow-release tablets: the usual dose is 240mg taken once a day, but it can be increased to 480mg a day, split into a morning dose and an evening dose 

• For angina or arrhythmias: usually between 40mg to 120mg daily, divided into doses, or 240mg twice a day with slow-release tablets 

• After a heart attack: 360mg of slow-release tablets a day, split into 2 or 3 doses, starting 1 week after your heart attack 

The dose you start on sometimes does not work well enough and your blood pressure does not lower enough, or your angina is not controlled. If this happens, your doctor will gradually increase your dose. Your dose may be lowered if your blood pressure is controlled or any side effects bother you. Always follow the instructions provided by your doctor or pharmacist[1]. 

Can you stop taking verapamil?

Do not stop taking verapamil suddenly without medical advice. Doing so can cause your condition to worsen. If you need to stop treatment, your doctor or pharmacist may advise reducing the dose gradually[1]. 

What do you do if you take too much verapamil?

Taking too much verapamil can be dangerous and may cause very low blood pressure, slow heart rate, dizziness, fainting, or collapse. Call 999 or go to A&E immediately if you think you or someone else has taken too much[1]. 

What do you do if you forget to take verapamil

If you forget a dose[1]: 

• Take it as soon as you remember 

• If it’s almost time for your next dose, skip the missed one 

• Do not take two doses at the same time 

What medicines can’t you take with verapamil?

Verapamil can interact with several other medicines. You should avoid or use caution if you are taking[1]: 

• Beta-blockers (such as atenolol) 

• Digoxin or ivabradine for heart failure 

• Statins (especially simvastatin) 

• Antiarrhythmic medicines (e.g. amiodarone) 

• Antidepressants (e.g. fluoxetine) 

• Antifungal medicines (e.g. itraconazole) 

• Anticonvulsants (e.g. carbamazepine) 

• Antibiotics (e.g. clarithromycin, erythromycin, rifampicin) 

• HIV or hepatitis C medication 

• Colchicine for gout 

• Immunosuppressants (e.g. ciclosporin, tacrolimus) 

• Grapefruit juice 

Always inform your doctor or pharmacist about all medications and supplements you take before you start a new medicine, and follow the instructions in the Patient Information Leaflet[2]. 

What are the side effects of verapamil?

Like all medicines, verapamil may cause side effects, though not everyone gets them. The most common side effects include[1]: 

• Constipation 

• Dizziness or tiredness 

• Headache 

• Flushing 

• Nausea or vomiting 

Serious side effects for which you should seek urgent medical attention include: 

• Swelling of the hands, feet, ankles, or legs 

• Very slow heart rate 

• Chest pain or fainting 

• symptoms of liver problems (e.g., yellowing of the skin or eyes, dark urine) 

You should contact your GP if you experience any of these symptoms. In rare cases, the medicine may cause a serious allergic reaction (anaphylaxis). You should call 999 or visit A&E immediately if you believe this is happening[1]. 

Symptoms of anaphylaxis include[1]:  

• Difficulty breathing  

• Tightness in throat and chest  

• Swelling of the tongue or throat  

• Feeling faint or dizzy  

• Blue/grey skin or lips  

• Loss of consciousness 

If you experience any side effects, including those not listed, you are encouraged to report them via the Yellow Card Scheme or contact your doctor, pharmacist, or nurse. This information is intended as a summary for general awareness and does not replace professional medical advice. 

The information provided in the side effects section is not a comprehensive list of all possible side effects associated with this medication. For a complete list of side effects, please refer to the Patient Information Leaflet (PIL) provided with your medication or consult your healthcare professional[2]. 

Frequently asked questions about verapamil

How quickly does verapamil work? 
It begins working within a few hours, but full effects may take several days[1]. 

Can I drink alcohol while taking verapamil? 
Yes but  in moderation,alcohol can make side effects like dizziness worse and increase the blood pressure lowering effects of verapamil[1].  

Can I take verapamil long-term? 
Yes, it is commonly used for long-term treatment when monitored appropriately[1]. 

Can I drive while taking verapamil? 
Yes, unless you feel dizzy, tired or unwell[1]. 

What foods should I avoid? 
Avoid grapefruit and grapefruit juice. These can make the side effects of verapamil worse[1]. 

For the official NHS guide for verapamil, visit their website.