Tadalafil and Prochlorperazine: Can You Take Them Together?

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Key takeaways

• No major direct interaction is commonly reported between tadalafil and prochlorperazine.
• Both medicines can lower blood pressure, so dizziness may increase—stand up slowly.
• Your prescriber checks your full medication list and health history during consultation.
• Never take tadalafil with nitrates, nicorandil, riociguat, or poppers—this is dangerous.
• See your GP if you experience new erectile dysfunction, as it can signal heart disease or diabetes.

What is tadalafil and how does it work?

Tadalafil is a prescription medicine licensed in the UK for treating erectile dysfunction in adult men [4]. It belongs to a group of medicines called PDE5 inhibitors, which work by relaxing blood vessels in the penis, allowing increased blood flow when you are sexually aroused. Unlike some other ED treatments, tadalafil does not cause an erection on its own—sexual stimulation is still needed.

Tadalafil is available in two main dosing schedules. The on-demand option (usually 10mg or 20mg) is taken at least 30 minutes before sexual activity, with effects lasting up to 36 hours—earning it the nickname 'the weekend pill' [4]. The daily option (2.5mg or 5mg) is taken once every day at the same time, allowing for more spontaneous sexual activity. Both generic and branded versions (Cialis) are available through UK pharmacies after a consultation with a prescriber.

Common side effects of tadalafil include headache, indigestion, back pain, muscle aches, flushing, and nasal congestion [4]. These are usually mild and temporary. Tadalafil is not suitable for everyone—it must not be taken with nitrates, nicorandil, riociguat, or recreational drugs called 'poppers', as this combination can cause a dangerous drop in blood pressure.

What is prochlorperazine used for?

Prochlorperazine is a prescription medicine that belongs to a group called phenothiazines. It is most commonly used to treat nausea and vomiting, including severe morning sickness, and to manage symptoms of vertigo (a spinning sensation) and inner ear problems such as Ménière's disease. It works by blocking dopamine receptors in the brain, which helps to reduce feelings of sickness and restore balance.

Prochlorperazine is available in several forms in the UK, including tablets (usually 5mg), buccal tablets that dissolve between the gum and cheek, and injections for hospital use. The usual dose for nausea is 5mg to 10mg, taken up to three times a day, though your doctor will tailor the dose to your individual needs.

Like all medicines, prochlorperazine can cause side effects. Common ones include drowsiness, dizziness, dry mouth, and blurred vision. Because it can affect alertness, you should be cautious when driving or operating machinery until you know how it affects you. Prochlorperazine can also lower blood pressure, particularly when you stand up quickly, which may cause light-headedness or fainting in some people.

How prochlorperazine affects blood pressure

One of the known effects of prochlorperazine is that it can cause postural hypotension—a drop in blood pressure when you change position, such as standing up from sitting or lying down. This happens because phenothiazines like prochlorperazine can block certain receptors (alpha-adrenergic receptors) that normally help maintain blood pressure when you move. The result can be dizziness, light-headedness, or even fainting, especially when you first start taking the medicine or if the dose is increased.

At a glance

Can you take tadalafil and prochlorperazine together?

There is no major direct drug interaction commonly reported between tadalafil and prochlorperazine, and many men take both medicines without problems. However, there is an important consideration: both medicines can lower blood pressure, and taking them together may add to this effect. Tadalafil works by relaxing blood vessels, which can cause a mild drop in blood pressure, while prochlorperazine can cause postural hypotension (a drop in blood pressure when standing up).

When these blood-pressure-lowering effects combine, some people may experience dizziness, light-headedness, or fainting, particularly when standing up quickly. This does not mean the combination is unsafe for everyone, but it does mean your prescriber needs to know about both medicines during your consultation. They will assess your overall health, blood pressure, and other medications to decide whether the combination is appropriate for you and whether any dose adjustments are needed.

If you are already taking prochlorperazine and your prescriber approves tadalafil, you may be advised to start on a lower dose of tadalafil and to be cautious when standing up, especially in the first few days. Never start, stop, or change the dose of either medicine without consulting your doctor or pharmacist first.

What your prescriber checks before approving tadalafil and prochlorperazine

When you request tadalafil through Cured Pharmacy, a UK-registered prescriber reviews your online consultation to ensure the treatment is safe and suitable for you. If you are taking prochlorperazine, the prescriber will pay particular attention to your blood pressure history, any symptoms of dizziness or fainting, and whether you take any other medicines that affect blood pressure.

The prescriber will also check that you do not have any conditions that make tadalafil unsuitable, such as recent heart attack or stroke, unstable angina, severe heart failure, very low blood pressure, or a history of sudden vision loss (NAION) [4]. They will review your full medication list to rule out dangerous combinations, such as nitrates, nicorandil, riociguat, or other PDE5 inhibitors, which must never be taken with tadalafil.

If you take other medicines that lower blood pressure—such as antihypertensives, alpha-blockers for prostate problems, or certain antidepressants—the prescriber will consider the cumulative effect. In some cases, they may recommend starting with a lower dose of tadalafil (such as 10mg instead of 20mg for on-demand use, or 2.5mg for daily use) to minimise the risk of dizziness. Honest and complete answers in your consultation are essential for your safety.

Why you must declare all your medicines

It is vital to list every medicine you take—prescription, over-the-counter, herbal remedies, and supplements—during your online consultation. Some interactions are not obvious: for example, St John's wort (a herbal remedy for low mood) can make tadalafil less effective, while grapefruit juice can increase tadalafil levels in your blood. Your prescriber relies on the information you provide to make safe prescribing decisions, so never leave anything out, even if you think it is unimportant.

Practical advice for taking tadalafil and prochlorperazine safely

If your prescriber approves the combination of tadalafil and prochlorperazine, there are some practical steps you can take to reduce the risk of side effects. First, be cautious when standing up, especially from lying down or sitting. Stand up slowly and pause for a moment to let your blood pressure adjust—this simple habit can prevent dizziness and falls.

Avoid drinking large amounts of alcohol when taking either medicine. Alcohol can worsen erectile dysfunction, increase the blood-pressure-lowering effect of both tadalafil and prochlorperazine, and make dizziness more likely [1]. Staying well hydrated (with water, not alcohol) and avoiding very hot baths or saunas can also help, as heat can dilate blood vessels and lower blood pressure further.

If you experience persistent dizziness, fainting, or feel unwell after taking the combination, contact your GP or pharmacist for advice. Do not simply stop taking prochlorperazine without medical guidance, as it has been prescribed for a reason. Your doctor may be able to adjust the timing of your doses, reduce the dose of one or both medicines, or suggest an alternative treatment. Always follow the dosing instructions for both medicines and never take more tadalafil than prescribed—taking extra will not improve the effect but will increase the risk of side effects.

Other ED treatment options available at Cured Pharmacy

Tadalafil is just one of several effective ED treatments available through Cured Pharmacy after an online consultation with a UK prescriber. Sildenafil (generic Viagra) is the most well-known option, taken about one hour before sexual activity with effects lasting around four to six hours [3]. It is available in 25mg, 50mg, and 100mg strengths, with the maximum dose being once per day.

Vardenafil (generic Levitra) works in a similar way to sildenafil and is taken 25 to 60 minutes before sex, while avanafil (Spedra) is the fastest-acting PDE5 inhibitor, often working within 15 to 30 minutes [5][6]. All of these medicines work by the same mechanism as tadalafil—relaxing blood vessels in the penis to improve blood flow—and all require sexual stimulation to be effective.

If you find that one PDE5 inhibitor does not suit you, another may work better or cause fewer side effects. Your prescriber can discuss the options during your consultation and help you choose the most appropriate treatment based on your lifestyle, health, and preferences. Remember, all PDE5 inhibitors share the same important safety warnings: do not take them with nitrates, nicorandil, riociguat, poppers, or another PDE5 inhibitor, and always declare your full medication list.

When to see your GP about erectile dysfunction

While online pharmacies like Cured Pharmacy offer convenient access to ED treatment, it is important to see your GP if you are experiencing erectile dysfunction for the first time. ED can be an early warning sign of underlying health conditions such as heart disease, high blood pressure, or diabetes [1][2]. Your GP can arrange tests, review your overall health, and address any contributing factors such as stress, anxiety, or relationship issues. Treating ED is important, but so is understanding and managing its root causes.

When to get urgent help

• Erection lasting more than 4 hours (priapism)—go to A&E immediately
• Sudden loss of vision or hearing—stop tadalafil and seek urgent medical help
• Chest pain during or after sex—call 999; do not take nitrate sprays if you have used tadalafil
• Severe dizziness, fainting, or collapse—call 999 or go to A&E
• Allergic reaction (swelling of face, lips, tongue, or throat, difficulty breathing)—call 999

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

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