Can You Take Sildenafil and Verapamil Together?

Takes less than 2 minutes to complete 100% online

At a glance

What Is Sildenafil and How Does It Work?

Sildenafil is a prescription medicine used to treat erectile dysfunction (ED) in men. It belongs to a group of medicines called phosphodiesterase type 5 (PDE5) inhibitors [3]. Sildenafil works by relaxing the blood vessels in the penis, which increases blood flow and helps you get and keep an erection when you are sexually aroused. It does not work without sexual stimulation.

Sildenafil is available in three strengths: 25 mg, 50 mg, and 100 mg. You usually take it about one hour before sexual activity, and it can remain effective for around four to five hours [3]. The most common brand name is Viagra, but generic sildenafil is widely available and works in exactly the same way. At Cured Pharmacy, sildenafil is available from £0.45 per tablet after an online consultation with a UK prescriber.

Common side effects include headache, flushing, indigestion, and nasal congestion [3]. Sildenafil must never be taken with nitrates (such as GTN spray or isosorbide mononitrate), nicorandil, riociguat, or recreational drugs known as 'poppers', because the combination can cause a dangerous drop in blood pressure [3].

What Is Verapamil and Why Is It Prescribed?

Verapamil is a medicine called a calcium channel blocker, used to treat high blood pressure (hypertension), angina (chest pain caused by reduced blood flow to the heart), and certain abnormal heart rhythms (arrhythmias). It works by relaxing and widening blood vessels, which lowers blood pressure and reduces the workload on the heart. Verapamil also slows down the heart rate in some people.

Verapamil is available in immediate-release tablets (usually taken two or three times a day) and modified-release (prolonged-release) capsules or tablets taken once or twice daily. Common side effects include constipation, headache, dizziness, ankle swelling, and fatigue. Because verapamil lowers blood pressure, combining it with other medicines that also reduce blood pressure—including sildenafil—can increase the risk of dizziness or feeling faint.

Verapamil can also affect how the body processes other medicines. It is a moderate inhibitor of an enzyme system in the liver called CYP3A4, which means it can increase the levels of certain drugs in the bloodstream, including some (but not all) PDE5 inhibitors.

How Do Sildenafil and Verapamil Interact?

When considering sildenafil and verapamil together, there are two main interaction mechanisms to understand. First, both medicines can lower blood pressure. Sildenafil relaxes blood vessels in the penis and elsewhere in the body, which can cause a small drop in blood pressure [3]. Verapamil also lowers blood pressure by relaxing blood vessels. When taken together, the blood-pressure-lowering effects can add up, potentially causing dizziness, light-headedness, or fainting, especially when standing up quickly.

Second, verapamil is a moderate inhibitor of the liver enzyme CYP3A4, which is involved in breaking down sildenafil. This means verapamil may slightly increase the amount of sildenafil in your bloodstream, which could make side effects such as headache or flushing more noticeable [3]. However, this interaction is generally considered manageable, and sildenafil is not contraindicated with verapamil.

The British National Formulary notes that the combination of sildenafil and calcium channel blockers such as verapamil may enhance the blood-pressure-lowering effect, but it does not list verapamil as a contraindication [3]. Your prescriber will assess your overall cardiovascular health, current blood pressure control, and other medicines before deciding whether sildenafil is suitable for you.

Is the Interaction Dangerous?

For most men, the interaction between sildenafil and verapamil is not dangerous, provided the prescriber has reviewed your medical history and current treatment. The key is to start on the lowest effective dose of sildenafil and monitor for symptoms such as dizziness or light-headedness. If you experience these symptoms, sit or lie down until they pass, and let your prescriber know at your next review. Do not drive or operate machinery if you feel dizzy.

What you need to know

• Sildenafil and verapamil are not contraindicated but both can lower blood pressure.
• Verapamil may slightly increase sildenafil levels, making side effects more noticeable.
• Your prescriber will start you on the lowest sildenafil dose and check your blood pressure control.
• Watch for dizziness or light-headedness and avoid heavy alcohol or grapefruit juice.
• Never take sildenafil with nitrates, nicorandil, or riociguat—this is dangerous.

What Your Prescriber Will Check Before Approving Sildenafil

Before prescribing sildenafil to someone taking verapamil, a UK prescriber will carry out a thorough clinical assessment. They will ask about your current blood pressure readings, whether your blood pressure is well controlled on verapamil, and whether you have experienced any dizziness, fainting, or chest pain. They will also review all your other medicines to check for any additional interactions.

The prescriber will ask about your cardiovascular history, including any heart attack, stroke, unstable angina, severe heart failure, or abnormal heart rhythms. Sexual activity places extra demand on the heart, so sildenafil is not suitable if your doctor has advised you to avoid sexual activity [3]. The prescriber will also check that you are not taking any nitrates, nicorandil, riociguat, or other PDE5 inhibitors, as these are absolute contraindications.

If you are stable on verapamil and your blood pressure is well controlled, the prescriber will usually start you on the lowest dose of sildenafil (25 mg or 50 mg) and advise you to monitor for side effects. They may also suggest taking sildenafil at a different time of day from verapamil to minimise the peak blood-pressure-lowering effect, although this is not always necessary. Always follow the prescriber's instructions and do not adjust doses yourself.

Other Medicines the Prescriber Will Ask About

In addition to verapamil, your prescriber will ask about alpha-blockers (such as doxazosin or tamsulosin), other blood-pressure medicines, and any drugs that affect liver enzymes. If you take multiple blood-pressure-lowering medicines, the prescriber may choose a lower starting dose of sildenafil or recommend extra caution. Always declare every medicine you take, including over-the-counter products and herbal supplements such as St John's wort.

Practical Advice for Taking Sildenafil with Verapamil

If your prescriber approves sildenafil while you are on verapamil, follow these practical steps to use it safely. Take sildenafil exactly as prescribed—usually 25 mg or 50 mg about one hour before sexual activity, with or without food. Do not take more than one dose in 24 hours. Avoid heavy or high-fat meals before taking sildenafil, as they can delay how quickly it works.

Monitor your blood pressure if you have a home monitor, especially in the first few days of using sildenafil. If you feel dizzy, light-headed, or faint, sit or lie down and avoid sudden movements. Do not stand up quickly from a sitting or lying position. Limit alcohol, as it can worsen dizziness and make it harder to get an erection. Grapefruit juice can increase sildenafil levels in the blood, so it is best avoided.

If you experience chest pain during or after sexual activity, stop and seek urgent medical help. Do not take a nitrate spray (GTN) if you have used sildenafil in the past 24 hours, as this combination is dangerous [3]. If you have an erection lasting more than four hours, or sudden loss of vision or hearing, go to A&E immediately. Keep your prescriber informed of any side effects or concerns.

When to get urgent help

• Erection lasting more than 4 hours (priapism)—go to A&E immediately
• Sudden loss of vision or hearing—seek urgent medical help
• Chest pain during or after sex—stop activity and call 999; do not take GTN if you have used sildenafil
• Severe dizziness, fainting, or very low blood pressure—seek same-day medical advice
• Allergic reaction (rash, swelling, difficulty breathing)—call 999

Call 999 or go to A&E in an emergency, or contact NHS 111 for urgent advice.

Alternatives to Sildenafil If You Take Verapamil

If sildenafil is not suitable for you, or if you experience troublesome side effects, other PDE5 inhibitors may be an option. Tadalafil (Cialis) is another widely used ED treatment that works in a similar way to sildenafil but lasts much longer—up to 36 hours [4]. Like sildenafil, tadalafil can lower blood pressure and may interact with verapamil, so the same precautions apply. Tadalafil is available on-demand (10 mg or 20 mg) or as a daily low dose (2.5 mg or 5 mg).

Vardenafil (Levitra) and avanafil (Spedra) are also PDE5 inhibitors licensed for ED [5][6]. Vardenafil works within 25 to 60 minutes, while avanafil can work in as little as 15 to 30 minutes. However, both are more sensitive to interactions with CYP3A4 inhibitors than sildenafil, so they may not be the first choice if you take verapamil. Your prescriber will advise which option is best for your individual circumstances.

Non-tablet treatments include Eroxon, a topical gel that works locally and does not interact with verapamil, and prescription treatments such as Vitaros (alprostadil cream) or Caverject (alprostadil injection) [7]. These may be considered if oral medicines are unsuitable. Addressing underlying causes—such as improving blood pressure control, losing weight, stopping smoking, and managing diabetes—can also improve erectile function [1][2].

When to See Your GP

If you have new or worsening erectile dysfunction, see your GP for a full assessment. ED can be an early warning sign of cardiovascular disease or diabetes [1][2]. Your GP can review your verapamil dose, check your blood pressure control, and refer you to a specialist if needed. Do not stop or change your verapamil without medical advice, as this could affect your heart or blood pressure.

Choose your treatment

Select from our recommended UK-licensed medications.

Answer quick questions

Select safe UK treatments. Quick answers.

Get it delivered fast

We will deliver direct to you as quickly as tomorrow.

Start Your Assessment For Erectile Dysfunction

Start your journey to better health today.

• Reviewed by UK-based prescribers
• Takes under 3 minutes
• Discreet Packaging