Tadalafil and Risperidone: Can They Be Taken Together?

Tadalafil and Risperidone: Understanding the Interaction

Published: 25 October 2026

Many men taking risperidone for mental health conditions wonder whether tadalafil and risperidone can be used together safely. The good news is that there is no major direct interaction between these two medicines, but your prescriber will carefully check your individual circumstances, particularly your blood pressure and overall cardiovascular health. This page explains what each medicine does, how they may affect each other, and what you need to know before starting treatment.

What Is Tadalafil and How Does It Work?

Tadalafil is a prescription medicine used to treat erectile dysfunction (ED) in men. It belongs to a group of medicines called PDE5 inhibitors, which work by relaxing the blood vessels in the penis, allowing more blood to flow in when you are sexually aroused [4]. Tadalafil does not cause an erection on its own—sexual stimulation is still needed for it to work.

Tadalafil is available in two main forms: on-demand tablets (usually 10mg or 20mg) taken at least 30 minutes before sexual activity, with effects lasting up to 36 hours, and daily low-dose tablets (2.5mg or 5mg) for men who prefer spontaneity [4]. The long duration of action is why tadalafil is sometimes called 'the weekend pill'. Common brand names include Cialis, but generic tadalafil is widely available and works in exactly the same way.

Like all PDE5 inhibitors, tadalafil can lower blood pressure slightly, which is usually not a problem for most men but becomes important when combined with certain other medicines or health conditions [4]. Your prescriber will assess your heart health and current medicines during the consultation to ensure tadalafil is safe for you.

What Is Risperidone and Why Is It Prescribed?

Risperidone is an antipsychotic medicine used to treat several mental health conditions, including schizophrenia, bipolar disorder, and sometimes severe behavioural problems. It works by affecting certain natural chemicals (neurotransmitters) in the brain, particularly dopamine and serotonin, helping to reduce symptoms such as hallucinations, delusions, and mood swings.

Risperidone can cause a range of side effects, and one that is particularly relevant here is its potential to contribute to erectile dysfunction. Antipsychotic medicines, including risperidone, can affect sexual function through several mechanisms: they may increase levels of the hormone prolactin, which can reduce testosterone and libido, and they can also affect the nervous system pathways involved in achieving and maintaining an erection. This means that some men taking risperidone may experience ED as a side effect of the medicine itself.

If you are taking risperidone and experiencing erectile difficulties, it is important not to stop or change your mental health medication without speaking to your GP or psychiatrist first. ED treatments like tadalafil may help manage the sexual side effects while you continue your essential mental health treatment, but this must be done under medical supervision.

Can Risperidone Cause Erectile Dysfunction?

Yes, risperidone is known to cause sexual side effects, including erectile dysfunction, reduced libido, and difficulty with ejaculation. These effects are thought to occur because risperidone increases prolactin levels and affects dopamine pathways, both of which play important roles in sexual function. If you have noticed ED symptoms since starting risperidone, discuss this with your prescriber—they may be able to adjust your dose or consider alternative treatments, and they can also assess whether tadalafil or another ED medicine might be appropriate for you.

The Interaction Between Tadalafil and Risperidone

There is no major direct pharmacological interaction between tadalafil and risperidone. This means that tadalafil does not significantly affect how risperidone works, and risperidone does not substantially change the levels or effectiveness of tadalafil in your body. Neither medicine is listed as a contraindication for the other, so they can be prescribed together when clinically appropriate.

However, both medicines can affect blood pressure. Tadalafil can cause a mild drop in blood pressure, and risperidone can also lower blood pressure, particularly when you stand up (a side effect called postural hypotension). When taken together, there is a theoretical risk that the blood-pressure-lowering effects could add up, potentially causing dizziness, light-headedness, or fainting, especially when standing up quickly.

This does not mean the combination is unsafe, but it does mean your prescriber will take extra care to check your blood pressure, review your cardiovascular health, and ensure you are not taking other medicines that also lower blood pressure. If you experience dizziness, fainting, or feel light-headed after starting tadalafil while on risperidone, contact your GP or pharmacist for advice. Most men tolerate the combination well, but individual assessment is essential.

What Your Prescriber Will Check Before Approving Tadalafil and Risperidone Together

When you request tadalafil through an online consultation at Cured Pharmacy, the UK-registered prescriber will review your full medical history and current medicines, including risperidone. They will specifically check your cardiovascular health, including any history of heart disease, stroke, or very low blood pressure, because tadalafil is not suitable when sexual activity itself is inadvisable [4].

The prescriber will also ask about other medicines you take, particularly any that lower blood pressure (such as antihypertensives or alpha-blockers), and whether you have experienced dizziness or fainting with risperidone. If you are stable on risperidone and your blood pressure is well controlled, tadalafil is usually considered safe to use, often starting with a lower dose to minimise the risk of side effects.

You must declare all your current medicines during the consultation, including over-the-counter products and herbal supplements. Never take tadalafil if you are also using nitrates (GTN spray, isosorbide mononitrate or dinitrate), nicorandil, riociguat, or recreational drugs called 'poppers' (amyl or alkyl nitrites), as this combination can cause a dangerous drop in blood pressure [4]. If you are unsure about any of your medicines, the prescriber will clarify during the consultation.

Starting Tadalafil While on Risperidone

If approved, your prescriber may recommend starting with a lower dose of tadalafil (such as 10mg on-demand or 2.5mg daily) to see how you tolerate it alongside risperidone. You should take tadalafil exactly as prescribed, and avoid drinking large amounts of alcohol, which can worsen ED and add to the blood-pressure-lowering effect. If the initial dose is effective and well tolerated, your prescriber may adjust it at a follow-up consultation.

Practical Advice for Using Tadalafil and Risperidone Safely

If you have been prescribed tadalafil while taking risperidone, there are several practical steps you can take to use both medicines safely. First, take tadalafil exactly as directed—on-demand tablets should be taken at least 30 minutes before sexual activity, and daily tablets should be taken at the same time each day. Do not take more than the prescribed dose, and never take another PDE5 inhibitor (such as sildenafil or vardenafil) on the same day.

Be aware of how you feel when you stand up, especially in the first few days after starting tadalafil. If you feel dizzy or light-headed, sit or lie down until it passes, and stand up slowly from sitting or lying positions. Avoid drinking heavily, as alcohol can make dizziness worse and reduce the effectiveness of tadalafil. Grapefruit juice can also increase tadalafil levels in your blood, so it is best to avoid it.

If you experience any unusual symptoms—such as a severe headache, chest pain during sex, sudden loss of vision or hearing, or an erection lasting more than four hours—seek urgent medical help. These are rare but serious side effects that require immediate attention. For less urgent concerns, such as mild headache, indigestion, or back pain (common side effects of tadalafil), speak to your pharmacist or GP if they persist or become bothersome [4].

Other ED Treatment Options and Tadalafil Alternatives

Tadalafil is just one of several effective ED treatments available in the UK. If tadalafil is not suitable for you, or if you would prefer a different option, your prescriber can discuss alternatives. Sildenafil (generic Viagra) is another PDE5 inhibitor that works in a similar way but has a shorter duration of action—about four to six hours—and is taken about one hour before sex [3]. Vardenafil (generic Levitra) and avanafil (Spedra) are also PDE5 inhibitors with slightly different onset times and durations [5][6].

All PDE5 inhibitors have similar interactions and precautions, so if you can take tadalafil safely with risperidone, you can usually take the other PDE5 inhibitors too, though your prescriber will confirm this. Some men prefer sildenafil because it is shorter-acting and they feel more in control of timing, while others prefer tadalafil's longer window of effectiveness, which allows for more spontaneity.

If PDE5 inhibitors are not suitable or effective, other options include alprostadil (available as a cream called Vitaros or an injection called Caverject), vacuum erection devices, or referral to a specialist for further assessment [7]. Addressing the underlying cause of ED—whether it is a side effect of risperidone, an undiagnosed health condition like diabetes or heart disease, or psychological factors—is also important, so speak to your GP if ED is a new or worsening problem [1][2].

Can You Switch from Risperidone to Reduce ED?

If risperidone is contributing to your erectile difficulties, your psychiatrist or GP may consider switching you to a different antipsychotic with a lower risk of sexual side effects, or adjusting your dose. However, you must never stop or change risperidone on your own, as this can cause your mental health symptoms to return or worsen. Any changes to your mental health medication must be made under the guidance of your prescriber, and ED treatment with tadalafil can often be used alongside risperidone to manage symptoms effectively.

Scientific References

1. NHS. (n.d.). Erectile dysfunction (impotence). NHS website. https://www.nhs.uk/conditions/erection-problems-erectile-dysfunction/ [accessed 25 October 2026]
2. National Institute for Health and Care Excellence. (n.d.). Erectile dysfunction. Clinical Knowledge Summaries. https://cks.nice.org.uk/topics/erectile-dysfunction/ [accessed 25 October 2026]
3. Joint Formulary Committee. (n.d.). Sildenafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/sildenafil/ [accessed 25 October 2026]
4. Joint Formulary Committee. (n.d.). Tadalafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/tadalafil/ [accessed 25 October 2026]
5. Joint Formulary Committee. (n.d.). Vardenafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/vardenafil/ [accessed 25 October 2026]
6. Joint Formulary Committee. (n.d.). Avanafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/avanafil/ [accessed 25 October 2026]
7. Joint Formulary Committee. (n.d.). Alprostadil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/alprostadil/ [accessed 25 October 2026]

Information on this page is for educational purposes only and is not medical advice. Prescription treatments require clinical assessment by a UK-registered prescriber. Always consult a qualified healthcare professional before starting or changing any medication.