Tadalafil and Hydroxychloroquine: Can You Take Them Together?
Learn about the interaction, what your prescriber checks, and how to use ED treatment safely.
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Tadalafil and Hydroxychloroquine: Understanding the Interaction
Published: 21 October 2026
Many men taking hydroxychloroquine for conditions such as rheumatoid arthritis or lupus wonder whether tadalafil and hydroxychloroquine can be taken together safely. The good news is that no major direct interaction between these two medicines is commonly reported, but your prescriber will still check your full medical history and current medications during your consultation to ensure tadalafil is suitable for you. This page explains what each medicine does, how they may affect each other, and the practical steps you should take.
Key takeaways
- No major direct interaction is commonly reported between tadalafil and hydroxychloroquine.
- Your prescriber will review all your medicines and health conditions during your consultation.
- Never take tadalafil with nitrates, nicorandil, riociguat, or poppers—this is dangerous.
- Continue your hydroxychloroquine as prescribed; do not stop without medical advice.
- Seek urgent help if you have chest pain, sudden vision loss, or an erection lasting over four hours.
What is tadalafil and how does it work?
Tadalafil is a prescription medicine used to treat erectile dysfunction (ED) in men [1]. It belongs to a group of medicines called phosphodiesterase type 5 (PDE5) inhibitors, which also includes sildenafil (Viagra), vardenafil (Levitra), and avanafil (Spedra) [3][4].
Tadalafil works by relaxing the blood vessels in the penis, allowing more blood to flow into the area when you are sexually aroused [4]. It does not cause an erection on its own—sexual stimulation is still needed. Tadalafil is available in two forms: on-demand tablets (10mg or 20mg taken at least 30 minutes before sex, with effects lasting up to 36 hours) and daily low-dose tablets (2.5mg or 5mg taken every day) [4].
Because tadalafil affects blood vessels throughout the body, it can lower blood pressure slightly. This is why your prescriber needs to know about all your current medicines, health conditions, and any heart or circulation problems before prescribing it [2][4].
What is hydroxychloroquine and why is it prescribed?
Hydroxychloroquine is a prescription medicine most commonly used to treat autoimmune conditions such as rheumatoid arthritis, systemic lupus erythematosus (SLE, or lupus), and certain skin conditions [12]. It was originally developed as an antimalarial drug and is still used for malaria prevention and treatment in some cases.
Hydroxychloroquine works by modulating the immune system, reducing inflammation and helping to control symptoms such as joint pain, swelling, and skin rashes. It is usually taken as a long-term daily tablet, and it can take several weeks or months to see the full benefit [12].
Common side effects of hydroxychloroquine include stomach upset, headache, and skin rashes. Rarely, it can affect the eyes (retinal damage) or heart rhythm, so people taking it long-term need regular monitoring by their doctor [12]. If you are taking hydroxychloroquine, it is important to tell your prescriber during your ED consultation.
At a glance
Do tadalafil and hydroxychloroquine interact with each other?
There is no major direct interaction commonly reported between tadalafil and hydroxychloroquine. This means that, in general, the two medicines do not interfere with each other's effectiveness or cause a dangerous reaction when taken together. However, every person's medical situation is different, and your prescriber will review your full medication list and health history during your consultation to ensure tadalafil is safe for you [2][4].
Hydroxychloroquine can, very rarely, affect heart rhythm (a condition called QT prolongation). Tadalafil can lower blood pressure slightly. While these effects are usually mild and manageable, your prescriber will check whether you have any heart conditions, take other medicines that affect the heart or blood pressure, or have other risk factors that might make the combination less suitable [4][12].
It is essential that you declare all your current medicines—prescription, over-the-counter, and herbal supplements—during your online consultation. Never stop or change a prescribed medicine like hydroxychloroquine without speaking to the doctor who prescribed it, as this could affect your underlying condition.
What your prescriber will check
During your consultation for tadalafil, the prescriber will ask about your current medicines (including hydroxychloroquine), any heart or circulation problems, blood pressure, recent strokes or heart attacks, and other health conditions [2]. They will also check whether you take any medicines that are known to interact dangerously with tadalafil, such as nitrates (GTN spray, isosorbide mononitrate), nicorandil, riociguat, or alpha-blockers like tamsulosin or doxazosin [3][4]. If you are stable on hydroxychloroquine and have no other contraindications, tadalafil may be prescribed at an appropriate dose for you.
Medicines that must not be taken with tadalafil
While tadalafil and hydroxychloroquine can generally be taken together, there are some medicines you must never take with tadalafil because the combination can cause a dangerous drop in blood pressure [3][4]. Do not take tadalafil if you use nitrates for chest pain (such as glyceryl trinitrate spray, isosorbide mononitrate, or isosorbide dinitrate), nicorandil, riociguat (for pulmonary hypertension), or recreational drugs called 'poppers' (amyl or alkyl nitrites) [4].
You should also never take two different PDE5 inhibitors at the same time—for example, do not take tadalafil and sildenafil together, or tadalafil on the same day as vardenafil or avanafil [3][4]. If you take alpha-blockers for an enlarged prostate (such as tamsulosin, doxazosin, or alfuzosin), you may still be able to use tadalafil, but you must be stable on the alpha-blocker first, and your prescriber will start you on the lowest dose of tadalafil to reduce the risk of dizziness or fainting [4].
Some medicines can raise the level of tadalafil in your blood, increasing the risk of side effects. These include potent CYP3A4 inhibitors such as ritonavir, cobicistat (found in some HIV medicines), ketoconazole, itraconazole, and clarithromycin. If you take any of these, your prescriber will adjust your tadalafil dose or may recommend a different ED treatment [4][12].
Declare all your medicines
Always list every medicine you take—including hydroxychloroquine, over-the-counter products, and herbal supplements—during your ED consultation. This helps your prescriber check for interactions and choose the safest, most effective treatment for you.
Practical advice for taking tadalafil with hydroxychloroquine
If your prescriber confirms that tadalafil is suitable for you, take it exactly as directed. For on-demand tadalafil (10mg or 20mg), take one tablet at least 30 minutes before you plan to have sex; the effect can last up to 36 hours, but you should not take more than one dose in 24 hours [4]. For daily tadalafil (2.5mg or 5mg), take one tablet at the same time every day, whether or not you plan to have sex [4].
Continue taking your hydroxychloroquine as prescribed by your doctor—do not stop or change the dose without medical advice. If you experience any new or unusual symptoms after starting tadalafil (such as dizziness, chest pain, sudden vision or hearing loss, or an erection lasting more than four hours), seek medical help immediately [1][4].
Avoid drinking large amounts of alcohol when using tadalafil, as alcohol can make erectile dysfunction worse and increase the risk of dizziness or low blood pressure [4]. Grapefruit juice can raise tadalafil levels in your blood, so it is best to avoid it. If you develop any side effects or have concerns, contact your prescriber or pharmacist for advice.
When to see your GP
If you are experiencing erectile dysfunction for the first time, it is important to see your GP for a full assessment. ED can be an early warning sign of underlying health problems such as heart disease, diabetes, or high blood pressure [1][2]. Your GP can check your overall health, review your medicines (including hydroxychloroquine), and refer you for specialist care if needed. Once any underlying causes have been addressed, your GP or an online prescriber can discuss ED treatment options with you.
How Cured Pharmacy can help with tadalafil and hydroxychloroquine
Cured Pharmacy is a GPhC-registered online pharmacy (GPhC 9012511) offering discreet, convenient access to ED treatments after a clinical consultation with a UK-registered prescriber. If you are taking hydroxychloroquine and would like to explore tadalafil for erectile dysfunction, you can complete a confidential online questionnaire that will be reviewed by a prescriber [2].
The prescriber will check your current medicines, health conditions, and any potential interactions before deciding whether tadalafil is safe and suitable for you. If approved, your medicine will be dispensed by our pharmacy and delivered discreetly to your door. We offer a range of ED treatments, including generic and branded tadalafil, sildenafil, vardenafil, and avanafil, so you can choose the option that best fits your needs and budget.
Our pharmacists are available to answer any questions you have about your treatment, side effects, or how to take your medicine safely alongside hydroxychloroquine or other medications. We are here to support you with clear, evidence-based advice in a non-judgemental and professional environment.
ED treatments available at Cured Pharmacy
We offer a wide range of prescription ED treatments to suit different preferences and budgets. Tadalafil (generic Cialis) is available from £7.95 (first order with code Ednew: £6.36), and sildenafil (generic Viagra) from £0.45 (first order with code Ednew: £0.36). We also stock branded options such as Cialis from £12.00 (first order with code Ednew: £9.60) and Viagra from £37.95 (first order with code Ednew: £30.36), as well as vardenafil (generic Levitra) from £16.95 (first order with code Ednew: £13.56) and Spedra (avanafil) from £20.95 (first order with code Ednew: £16.76). All treatments require a prescriber-reviewed consultation before supply.
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—call 999
- Severe dizziness, fainting, or very low blood pressure—seek same-day medical advice
- Allergic reaction (swelling of face, lips, tongue, or difficulty breathing)—call 999
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 21 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 21 October 2026]
- Joint Formulary Committee. (n.d.). Sildenafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/sildenafil/ [accessed 21 October 2026]
- Joint Formulary Committee. (n.d.). Tadalafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/tadalafil/ [accessed 21 October 2026]
- Electronic Medicines Compendium. (n.d.). Summaries of Product Characteristics and Patient Information Leaflets. https://www.medicines.org.uk/emc/ [accessed 21 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.
Common Questions
Can't find your answer? Our UK pharmacists review every consultation and can help.
Can I take tadalafil if I am on hydroxychloroquine for lupus?
Yes, in most cases. No major direct interaction is commonly reported between tadalafil and hydroxychloroquine, but your prescriber will review your full medical history and current medicines during your consultation to ensure tadalafil is safe for you.
Will hydroxychloroquine make tadalafil less effective?
No, hydroxychloroquine is not known to reduce the effectiveness of tadalafil. However, if you have concerns about how well your ED treatment is working, speak to your prescriber or pharmacist for advice.
Do I need to tell my rheumatologist that I am taking tadalafil?
It is good practice to keep all your doctors informed about the medicines you are taking, including ED treatments. Your rheumatologist can then consider this when reviewing your overall care and any new prescriptions.
Can I take tadalafil if I also take other medicines for rheumatoid arthritis?
Your prescriber will check all your current medicines during your consultation. Many medicines for rheumatoid arthritis can be taken safely with tadalafil, but you must declare everything you take so the prescriber can assess your individual situation.
What should I do if I get side effects from tadalafil while on hydroxychloroquine?
Common side effects of tadalafil include headache, indigestion, back pain, and flushing. If you experience severe or unusual symptoms (such as chest pain, sudden vision or hearing loss, or an erection lasting more than four hours), seek urgent medical help and inform your prescriber.
Is it safe to take tadalafil every day if I am on long-term hydroxychloroquine?
Daily low-dose tadalafil (2.5mg or 5mg) can be prescribed for some men, including those taking hydroxychloroquine, if the prescriber confirms it is suitable. Your prescriber will review your health and medicines to decide the best dosing schedule for you.
Can hydroxychloroquine cause erectile dysfunction?
Hydroxychloroquine is not commonly reported to cause erectile dysfunction. However, the underlying conditions it treats (such as lupus or rheumatoid arthritis) and other medicines you may be taking can contribute to ED, so it is important to discuss this with your GP or prescriber.
Will my online consultation ask about hydroxychloroquine?
Yes, the online consultation will ask you to list all your current medicines, including hydroxychloroquine. This allows the prescriber to check for interactions and ensure tadalafil is safe and appropriate for you.
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Reviewed by UK-based prescribers · Takes under 3 minutes · Discreet Packaging
Medically reviewed by
Tarun Kumar, Superintendent Pharmacist (GPhC 2233073)