Tadalafil and Chlorpromazine: Can They Be Taken Together?
UK pharmacist guidance on this interaction and safe use of ED treatment with antipsychotic medicines.
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Tadalafil and Chlorpromazine: What You Need to Know
Published: 19 October 2026
Tadalafil and chlorpromazine can usually be taken together, but the combination requires careful monitoring because both medicines can lower blood pressure. Chlorpromazine is an antipsychotic medicine used to treat schizophrenia and other mental health conditions, while tadalafil is a PDE5 inhibitor used to treat erectile dysfunction. This page explains how these medicines interact, what your prescriber will check, and how to use them safely.
Key takeaways
- Tadalafil and chlorpromazine can usually be taken together, but both lower blood pressure so careful monitoring is needed.
- Your prescriber will check your blood pressure history and may start tadalafil at a lower dose if you take chlorpromazine.
- Watch for dizziness or fainting when standing up, and avoid heavy alcohol while taking both medicines.
- Tell your prescriber about all medicines you take, including chlorpromazine, during your online consultation.
- Seek urgent help for chest pain during sex, an erection lasting over 4 hours, or sudden vision or hearing loss.
What is tadalafil and chlorpromazine used for?
Tadalafil is a prescription medicine licensed in the UK to treat erectile dysfunction (ED) in men. 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 [3][4]. Tadalafil is available as on-demand tablets (10mg or 20mg taken at least 30 minutes before sex, with effects lasting up to 36 hours) or as a daily low-dose tablet (2.5mg or 5mg). It is the generic version of Cialis and requires sexual stimulation to work.
Chlorpromazine is an antipsychotic medicine used to treat schizophrenia, bipolar disorder, severe anxiety, and other mental health conditions [12]. It works by blocking dopamine receptors in the brain, which helps to reduce symptoms such as hallucinations, delusions, and agitation. Chlorpromazine also has effects on other receptors in the body, including those that control blood pressure. It is usually taken as tablets or liquid, and the dose varies depending on the condition being treated.
Both medicines are prescription-only in the UK and should only be taken under the supervision of a healthcare professional. If you are taking chlorpromazine and are considering treatment for erectile dysfunction, it is essential that your prescriber knows about all your current medicines during the online consultation.
How do tadalafil and chlorpromazine interact?
The main interaction between tadalafil and chlorpromazine is that both medicines can lower blood pressure. Chlorpromazine causes blood pressure to drop by blocking certain receptors (alpha-adrenergic receptors) in blood vessels, which can lead to dizziness or fainting, especially when standing up quickly [12]. Tadalafil also lowers blood pressure slightly by relaxing blood vessels, although this effect is usually mild when the medicine is used for erectile dysfunction [4].
When taken together, the blood-pressure-lowering effects can add up, increasing the risk of dizziness, light-headedness, or fainting. This is particularly important if you are starting chlorpromazine, increasing the dose, or if you already experience low blood pressure or dizziness with either medicine. The interaction is not an absolute contraindication—meaning the medicines are not forbidden together—but your prescriber must assess your individual situation carefully.
There is no direct pharmacological interaction that makes one medicine interfere with how the other works in the body. The concern is purely about the combined effect on blood pressure. Your prescriber will check your blood pressure history, current dose of chlorpromazine, and any symptoms you have experienced before deciding whether tadalafil is suitable for you.
What does this mean in plain English?
In simple terms, both medicines can make your blood pressure drop a little. When you take them together, that drop can be more noticeable, which might make you feel dizzy or faint, especially when you stand up. Your prescriber will check whether this is likely to be a problem for you based on your medical history and current health. If you are stable on chlorpromazine and have no blood pressure issues, tadalafil can usually be prescribed safely, often starting at a lower dose.
At a glance
What will your prescriber check before prescribing tadalafil?
During your online consultation at Cured Pharmacy, the UK-registered prescriber will ask detailed questions about your current medicines, including chlorpromazine. They will want to know the dose you are taking, how long you have been on it, and whether you have experienced any side effects such as dizziness, fainting, or low blood pressure. This information helps them assess whether tadalafil is safe for you and, if so, what dose to start with [2][4].
The prescriber will also check your cardiovascular health, including any history of heart disease, stroke, or blood pressure problems. They will ask about other medicines you take, particularly any that also lower blood pressure (such as medicines for high blood pressure or alpha-blockers for prostate problems). If you are taking multiple medicines that affect blood pressure, the prescriber may recommend starting tadalafil at a lower dose or may advise alternative treatments.
It is essential to be honest and complete in your answers. Do not leave out any medicines, including over-the-counter products, herbal remedies, or recreational drugs. The prescriber cannot make a safe decision without knowing the full picture. If you are unsure about any aspect of your health or medicines, mention it during the consultation—there are no silly questions when it comes to your safety.
Practical advice for taking tadalafil and chlorpromazine together
If your prescriber approves tadalafil while you are taking chlorpromazine, follow their instructions carefully. You may be started on a lower dose of tadalafil (for example, 10mg on-demand rather than 20mg) to minimise the risk of low blood pressure. Take tadalafil only as prescribed—do not take more than one dose in 24 hours, and do not combine it with any other erectile dysfunction medicine [4].
Be cautious when standing up, especially after taking tadalafil. Sit on the edge of the bed or chair for a moment before standing to reduce the risk of dizziness. Avoid drinking large amounts of alcohol, as this can also lower blood pressure and make side effects worse. If you feel dizzy, light-headed, or faint after taking tadalafil, sit or lie down until the feeling passes, and contact your GP or pharmacist for advice.
Do not stop or change the dose of chlorpromazine without speaking to the doctor who prescribed it. Stopping antipsychotic medicines suddenly can cause withdrawal symptoms or a relapse of your mental health condition. If you experience any new or worsening symptoms—such as severe dizziness, chest pain, or an erection lasting more than four hours—seek medical help immediately. Keep both your GP and your mental health team informed that you are using tadalafil.
Tips for safe use
Always take tadalafil on an empty stomach or after a light meal for best results, and allow at least 30 minutes before sexual activity. Keep a list of all your medicines (including doses) on your phone or in your wallet, so you can share it easily with any healthcare professional. If you are prescribed a new medicine or your chlorpromazine dose changes, inform the prescriber who manages your tadalafil so they can review whether any adjustment is needed.
Most important safety tip
Always sit on the edge of the bed or chair for a moment before standing up after taking tadalafil, especially if you are on chlorpromazine. This simple step can help prevent dizziness or fainting caused by a sudden drop in blood pressure.
Warning signs and when to seek help
Most men taking tadalafil and chlorpromazine together do not experience serious problems, but it is important to know the warning signs that need urgent attention. If you develop chest pain or discomfort during or after sex, stop sexual activity immediately and seek medical help. Chest pain could indicate a heart problem, and you should not take another dose of tadalafil until you have been assessed by a doctor [1][4].
An erection that lasts longer than four hours (priapism) is a medical emergency. This is rare but can cause permanent damage to the penis if not treated quickly. Go to A&E or call 999 if this happens. Sudden loss of vision in one or both eyes, or sudden decrease or loss of hearing (sometimes with ringing in the ears or dizziness), also requires immediate medical attention, as these can be signs of serious side effects [4].
If you experience severe dizziness, fainting, or a rapid or irregular heartbeat, contact your GP or call 111 for advice. These symptoms may indicate that your blood pressure has dropped too low. Do not drive or operate machinery if you feel dizzy or light-headed. If you have any concerns about side effects or the interaction between your medicines, speak to a pharmacist or your prescriber—they are there to help you use your medicines safely.
Can other ED medicines be used with chlorpromazine?
All PDE5 inhibitors—sildenafil (Viagra), tadalafil (Cialis), vardenafil (Levitra), and avanafil (Spedra)—can lower blood pressure and therefore have a similar interaction with chlorpromazine. The same precautions apply: your prescriber will assess your individual risk and may start you on a lower dose. Sildenafil is usually taken about one hour before sex and lasts for around four to six hours, while tadalafil can last up to 36 hours, giving you more flexibility [3][4][5][6].
If you are taking chlorpromazine, you must not take tadalafil or any other PDE5 inhibitor together with nitrates (such as GTN spray or isosorbide mononitrate), nicorandil, riociguat, or recreational drugs called 'poppers' (amyl or alkyl nitrites). These combinations can cause a dangerous drop in blood pressure and are absolutely contraindicated [3][4]. Always tell your prescriber about every medicine you take, including those prescribed by different doctors or bought over the counter.
Other treatments for erectile dysfunction, such as alprostadil (Vitaros cream or Caverject injection), work in a different way and do not have the same blood pressure interaction with chlorpromazine, although they still require a prescription and careful assessment [7]. Your prescriber will discuss the best option for you based on your overall health, the severity of your ED, and your preferences. At Cured Pharmacy, all ED treatments are supplied only after an online consultation reviewed by a UK-registered prescriber.
Choosing the right treatment
If you have concerns about interactions or side effects, discuss them openly during your consultation. Your prescriber can explain the pros and cons of each medicine and help you choose the one that fits your lifestyle and health needs. Remember, erectile dysfunction can be an early warning sign of heart disease or diabetes, so if you have not seen your GP about ED before, it is worth making an appointment for a full health check [1][2].
When to get urgent help
- Chest pain or discomfort during or after sex—stop activity and seek immediate medical help
- An erection lasting longer than 4 hours (priapism)—go to A&E or call 999
- Sudden loss of vision in one or both eyes—seek immediate medical attention
- Sudden decrease or loss of hearing, possibly with ringing in the ears or dizziness—contact a doctor urgently
- Severe dizziness, fainting, or rapid/irregular heartbeat—call your GP or 111 for advice
Call 999 or go to A&E in an emergency, or contact NHS 111 for urgent advice.
Scientific References
- NHS. (n.d.). Erectile dysfunction (impotence). NHS website. https://www.nhs.uk/conditions/erection-problems-erectile-dysfunction/ [accessed 19 October 2026]
- National Institute for Health and Care Excellence. (n.d.). Erectile dysfunction. Clinical Knowledge Summaries. https://cks.nice.org.uk/topics/erectile-dysfunction/ [accessed 19 October 2026]
- Joint Formulary Committee. (n.d.). Sildenafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/sildenafil/ [accessed 19 October 2026]
- Joint Formulary Committee. (n.d.). Tadalafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/tadalafil/ [accessed 19 October 2026]
- Joint Formulary Committee. (n.d.). Vardenafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/vardenafil/ [accessed 19 October 2026]
- Joint Formulary Committee. (n.d.). Avanafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/avanafil/ [accessed 19 October 2026]
- Joint Formulary Committee. (n.d.). Alprostadil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/alprostadil/ [accessed 19 October 2026]
- Electronic Medicines Compendium. (n.d.). Summaries of Product Characteristics and Patient Information Leaflets. https://www.medicines.org.uk/emc/ [accessed 19 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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Can I take tadalafil if I am on chlorpromazine?
Yes, in most cases tadalafil can be taken with chlorpromazine, but your prescriber must assess your individual situation first. Both medicines can lower blood pressure, so you may be started on a lower dose of tadalafil and monitored for dizziness or fainting.
Will chlorpromazine stop tadalafil from working?
No, chlorpromazine does not interfere with how tadalafil works to improve erections. The concern is about the combined effect on blood pressure, not the effectiveness of the ED treatment.
What should I do if I feel dizzy after taking tadalafil and chlorpromazine together?
Sit or lie down until the dizziness passes. Avoid standing up quickly. If the dizziness is severe or does not go away, contact your GP or call 111 for advice.
Can I drink alcohol while taking tadalafil and chlorpromazine?
It is best to limit alcohol, as it can also lower blood pressure and increase the risk of dizziness or fainting. Heavy drinking can also make erectile dysfunction worse.
Do I need to tell my psychiatrist that I am taking tadalafil?
Yes, it is a good idea to keep all your healthcare professionals informed. Your psychiatrist should know about any new medicines you start, and your ED prescriber needs to know about your chlorpromazine.
Can I take sildenafil (Viagra) instead of tadalafil if I am on chlorpromazine?
Sildenafil has a similar interaction with chlorpromazine, as both are PDE5 inhibitors that can lower blood pressure. Your prescriber will assess which medicine is best for you based on your health and preferences.
What if my chlorpromazine dose changes—do I need to tell my ED prescriber?
Yes, any change in your chlorpromazine dose could affect your blood pressure and the safety of tadalafil. Inform the prescriber who manages your ED treatment so they can review your treatment plan.
Are there any ED treatments that do not interact with chlorpromazine?
All PDE5 inhibitors (sildenafil, tadalafil, vardenafil, avanafil) have a similar interaction. Other treatments such as alprostadil work differently and may be an option, but they still require a prescription and careful assessment by a healthcare professional.
Medically reviewed by
Tarun Kumar, Superintendent Pharmacist (GPhC 2233073)