Tadalafil and Paliperidone: Can They Be Taken Together?

Tadalafil and Paliperidone: Understanding the Interaction

Published: 24 October 2026

If you're prescribed paliperidone for mental health and considering tadalafil for erectile dysfunction, you may wonder whether tadalafil and paliperidone can be taken together safely. The good news is that no major direct interaction between these two medicines is commonly reported in clinical practice, but your prescriber will still need to review your full medication list and health history before approving tadalafil. This page explains what each medicine does, how they may affect each other, what your doctor or pharmacist checks, and the practical steps to take if you're using both.

What Is Tadalafil and How Does It Work?

Tadalafil is a prescription medicine used to treat erectile dysfunction (ED) in men [3][4]. It belongs to a group of medicines called PDE5 inhibitors, which work by relaxing blood vessels in the penis, allowing more blood to flow in when you are sexually aroused. 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 10 mg or 20 mg) taken at least 30 minutes before sexual activity, with effects lasting up to 36 hours, and daily low-dose tablets (2.5 mg or 5 mg) taken once a day to allow more spontaneity [4]. The branded version is known as Cialis, but generic tadalafil is widely available and just as effective.

Common side effects include headache, indigestion, back pain, muscle aches, and flushing. Most side effects are mild and temporary. Tadalafil is not suitable for everyone—particularly those taking nitrates, nicorandil, riociguat, or poppers, as the combination can cause a dangerous drop in blood pressure [4].

What Is Paliperidone and Why Is It Prescribed?

Paliperidone is an antipsychotic medicine used to treat schizophrenia and schizoaffective disorder [12]. It works by helping to restore the balance of certain natural substances (neurotransmitters) in the brain, particularly dopamine and serotonin. Paliperidone is available as extended-release tablets (taken once daily) and as a long-acting injection given every month or every three months.

Like many antipsychotic medicines, paliperidone can sometimes contribute to sexual side effects, including erectile dysfunction, reduced libido, and difficulties with ejaculation. These effects are thought to be related to changes in hormone levels (particularly prolactin) and neurotransmitter activity in the brain.

If you are experiencing erectile difficulties while taking paliperidone, it is important to discuss this with your prescribing doctor. They can assess whether the ED is related to the medication, an underlying health condition, psychological factors, or a combination of these. Never stop or reduce paliperidone without medical advice, as this can lead to a relapse of your mental health condition.

Can Paliperidone Cause Erectile Dysfunction?

Yes, paliperidone and other antipsychotic medicines can contribute to erectile dysfunction. This happens because antipsychotics can increase levels of a hormone called prolactin, which in turn can lower testosterone and affect sexual function. The effect varies from person to person—some men experience significant sexual side effects, while others notice little or no change. If ED develops or worsens after starting paliperidone, your doctor may be able to adjust the dose, switch to a different antipsychotic, or recommend treatment for the ED itself, such as tadalafil.

Tadalafil and Paliperidone: Is There an Interaction?

There is no major direct pharmacological interaction between tadalafil and paliperidone that would make the combination unsafe or contraindicated. Neither medicine significantly affects the breakdown or activity of the other in the body, and they work through different mechanisms—tadalafil on blood vessels in the penis, and paliperidone on neurotransmitters in the brain.

However, both medicines can, in theory, lower blood pressure. Tadalafil does this by dilating blood vessels, and paliperidone (like other antipsychotics) can cause postural hypotension (a drop in blood pressure when you stand up), especially when you first start taking it or after a dose increase. If you are taking both, there is a small possibility that the blood-pressure-lowering effects could add together, leading to dizziness, light-headedness, or fainting.

For this reason, your prescriber will carefully review your current medication, blood pressure, and overall health before approving tadalafil. They may start you on a lower dose of tadalafil and advise you to monitor for any symptoms of low blood pressure, such as feeling faint or dizzy when standing up. Most men tolerate the combination well, but individual assessment is essential.

What Your Prescriber Checks Before Approving Tadalafil and Paliperidone

When you request tadalafil through an online consultation at Cured Pharmacy, the UK-registered prescriber will review your full medical history and current medications, including paliperidone. They will check your blood pressure, cardiovascular health, and any other conditions that might affect the safety of tadalafil.

The prescriber will also ask about any other medicines you take, including over-the-counter products and herbal supplements, to identify potential interactions. For example, if you are also taking an alpha-blocker (such as doxazosin or tamsulosin) for prostate symptoms, or a potent CYP3A4 inhibitor (such as ritonavir or ketoconazole), the prescriber will need to adjust the tadalafil dose or consider whether it is safe to proceed [4].

You must declare all your current medicines during the consultation. Do not assume that because tadalafil and paliperidone do not have a major direct interaction, the combination is automatically safe for you—other factors, such as your blood pressure, heart health, and additional medications, all play a role in the decision.

Starting Tadalafil While on Paliperidone

If you are stable on paliperidone and your prescriber approves tadalafil, they may recommend starting with a lower dose (such as 10 mg on-demand or 2.5 mg daily) to see how you respond. Take the first dose at a time when you can monitor for side effects, and avoid activities that require alertness (such as driving) until you know how the combination affects you. If you experience dizziness, fainting, or any other concerning symptoms, contact your doctor or pharmacist promptly.

Practical Advice for Taking Tadalafil and Paliperidone Together

If your prescriber has approved tadalafil while you are taking paliperidone, follow these practical steps to use both medicines safely. First, take each medicine exactly as prescribed—do not increase the dose of tadalafil or take it more often than recommended, even if you do not notice immediate results. Tadalafil requires sexual stimulation to work, and it may take a few attempts to find the right dose and timing for you.

Be mindful of your blood pressure. Stand up slowly from sitting or lying down, especially in the first few hours after taking tadalafil, to reduce the risk of dizziness or fainting. Avoid drinking large amounts of alcohol, as this can worsen erectile dysfunction, increase the risk of low blood pressure, and reduce the effectiveness of tadalafil [4].

Keep your mental health team informed. If you notice any changes in your mood, mental health symptoms, or side effects from paliperidone after starting tadalafil, let your psychiatrist or mental health nurse know. Similarly, if tadalafil does not help your erectile dysfunction, or if you experience side effects such as severe headache, chest pain, or an erection lasting more than four hours, seek medical advice immediately. Never stop or change your paliperidone dose without consulting your prescribing doctor, as this can lead to a relapse of your mental health condition.

Other Medicines and Lifestyle Factors to Consider with Tadalafil

While tadalafil and paliperidone can usually be taken together, other medicines you are taking may pose more significant interactions. Never take tadalafil with nitrates (such as GTN spray or isosorbide mononitrate), nicorandil, riociguat, or recreational drugs known as poppers (amyl or alkyl nitrites), as the combination can cause a dangerous drop in blood pressure [4]. Do not take tadalafil with another PDE5 inhibitor (such as sildenafil or vardenafil) at the same time.

If you take an alpha-blocker for prostate symptoms (such as tamsulosin or doxazosin), your prescriber will need to ensure you are stable on the alpha-blocker before starting tadalafil, and they will usually recommend the lowest effective dose of tadalafil [4]. Potent CYP3A4 inhibitors (such as ritonavir, cobicistat, ketoconazole, or clarithromycin) can increase tadalafil levels in the blood, requiring a dose reduction [4].

Lifestyle factors also matter. Smoking, excessive alcohol, obesity, lack of exercise, and poorly controlled diabetes or high blood pressure can all contribute to erectile dysfunction [1][2]. Addressing these factors—alongside medication—can improve your results. If you have not seen a GP about your erectile dysfunction, consider doing so, as ED can be an early warning sign of cardiovascular disease or diabetes [1][2].

When to Seek Urgent Medical Help

Seek emergency help (call 999 or go to A&E) if you experience an erection lasting more than four hours (priapism), sudden loss of vision or hearing, or chest pain during sexual activity. These are rare but serious side effects that require immediate treatment. If you feel faint, dizzy, or unwell after taking tadalafil, especially in combination with other blood-pressure-lowering medicines, sit or lie down and seek medical advice promptly.

Scientific References

1. NHS. (n.d.). Erectile dysfunction (impotence). NHS website. https://www.nhs.uk/conditions/erection-problems-erectile-dysfunction/ [accessed 24 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 24 October 2026]
3. Joint Formulary Committee. (n.d.). Sildenafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/sildenafil/ [accessed 24 October 2026]
4. Joint Formulary Committee. (n.d.). Tadalafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/tadalafil/ [accessed 24 October 2026]
5. Electronic Medicines Compendium. (n.d.). Summaries of Product Characteristics and Patient Information Leaflets. https://www.medicines.org.uk/emc/ [accessed 24 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.

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