Tadalafil and Infliximab: Can They Be Taken Together?

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At a glance

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 (phosphodiesterase type 5) inhibitors, which work by relaxing the blood vessels in the penis, allowing increased blood flow when you are sexually aroused [4]. Tadalafil does not cause an erection on its own—sexual stimulation is still needed.

Tadalafil is available in two 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 longer duration of action is why tadalafil is sometimes called the 'weekend pill'. Common brand names include Cialis, but generic tadalafil is widely available and equally effective.

Because tadalafil can lower blood pressure slightly, it must not be taken with certain medicines—particularly nitrates (such as GTN spray), nicorandil, riociguat, or recreational drugs called 'poppers' [4]. These combinations can cause a dangerous drop in blood pressure. Your prescriber will check for these and other important interactions before approving treatment.

What Is Infliximab and Why Is It Prescribed?

Infliximab is a biologic medicine—a type of immunosuppressant—used to treat a range of inflammatory conditions. It works by blocking a protein in the body called tumour necrosis factor alpha (TNF-alpha), which plays a key role in inflammation [12]. By reducing TNF-alpha activity, infliximab helps control symptoms and prevent disease progression.

Common conditions treated with infliximab include Crohn's disease, ulcerative colitis, rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis, and severe plaque psoriasis [12]. It is usually given as an intravenous infusion in a hospital or clinic setting, with the frequency depending on the condition being treated and your response to therapy.

Because infliximab suppresses part of the immune system, it can increase the risk of infections and requires careful monitoring by your specialist. However, it does not directly affect the cardiovascular system or blood pressure in the way that some other medicines do, which is relevant when considering interactions with ED treatments like tadalafil.

Does Infliximab Cause Erectile Dysfunction?

Inflammatory conditions themselves—such as Crohn's disease and rheumatoid arthritis—can contribute to erectile dysfunction through several mechanisms, including chronic inflammation, fatigue, pain, and the psychological impact of living with a long-term condition [1][10]. Some men may notice ED improves once their underlying condition is better controlled with treatment like infliximab, while others may continue to experience difficulties. If you are concerned about ED, it is worth discussing with your GP or specialist, as effective treatments are available.

Tadalafil and Infliximab: Is There an Interaction?

No major interaction is commonly reported between tadalafil and infliximab [2][4]. This means that, in most cases, men taking infliximab can safely use tadalafil for erectile dysfunction, provided there are no other contraindications. Infliximab does not significantly affect the liver enzymes (CYP3A4) responsible for breaking down tadalafil, so it does not alter tadalafil levels in the blood in a clinically meaningful way.

However, it is essential to remember that every person's medical situation is unique. Your prescriber will review all your current medicines, including infliximab and any other treatments for your inflammatory condition, during the online consultation. They will also check for other factors that might affect the safety of tadalafil, such as heart conditions, blood pressure, and other medications you may be taking alongside infliximab (for example, corticosteroids or other immunosuppressants).

If you are taking infliximab and are considering tadalafil for ED, you should declare all your medicines during the consultation. Do not stop or change any prescribed medicine, including infliximab, without advice from the doctor or specialist who prescribed it. The consultation process ensures that tadalafil is both safe and appropriate for you.

What you need to know

• No major interaction is commonly reported between tadalafil and infliximab—they can usually be taken together safely.
• Your prescriber reviews all your medicines during the online consultation to ensure tadalafil is suitable for you.
• Never take tadalafil with nitrates, nicorandil, riociguat, or 'poppers'—this can cause dangerous low blood pressure.
• Inflammatory conditions can contribute to ED; treating the underlying condition and using tadalafil may both help.
• Cured Pharmacy offers confidential, UK prescriber-led consultations and discreet home delivery of tadalafil.

What Your Prescriber Checks Before Approving Tadalafil

When you request tadalafil through an online pharmacy like Cured Pharmacy, a UK-registered prescriber will review a detailed health questionnaire. They will check for 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 (non-arteritic anterior ischaemic optic neuropathy, or NAION) [2][4].

The prescriber will also review all your current medicines to identify potential interactions. Tadalafil must never be taken with nitrates (GTN spray, isosorbide mononitrate or dinitrate), nicorandil, riociguat, or recreational 'poppers', as these combinations can cause a dangerous fall in blood pressure [4]. If you take alpha-blockers (such as tamsulosin or doxazosin) for prostate symptoms, you may still be able to use tadalafil, but you must be stable on the alpha-blocker and start on the lowest dose of tadalafil.

Medicines that strongly inhibit the liver enzyme CYP3A4—such as ritonavir, cobicistat, ketoconazole, itraconazole, or clarithromycin—can raise tadalafil levels, requiring dose adjustments or making tadalafil unsuitable [4]. Your prescriber will check the summary of product characteristics (SmPC) for any medicine you are taking to ensure safe prescribing. This thorough review protects your safety and ensures tadalafil is the right choice for you.

Starting Tadalafil While on Infliximab

If you are already established on infliximab and your inflammatory condition is stable, starting tadalafil is usually straightforward, provided there are no other contraindications. Your prescriber may start you on a lower dose (such as tadalafil 10mg on-demand) to assess your response and tolerability. You can then adjust the dose if needed, up to a maximum of 20mg on-demand or 5mg daily, depending on effectiveness and side effects [4]. Always follow the prescriber's instructions and do not exceed the recommended dose.

Practical Advice for Taking Tadalafil with Infliximab

If your prescriber approves tadalafil, take it exactly as directed. For on-demand tadalafil (10mg or 20mg), take one tablet at least 30 minutes before sexual activity; the effect can last up to 36 hours, so you do not need to rush [4]. For daily tadalafil (2.5mg or 5mg), take one tablet at the same time each day, allowing you to be ready for sexual activity at any time. Tadalafil requires sexual stimulation to work—it will not cause an automatic erection.

You can take tadalafil with or without food, although a very heavy or high-fat meal may delay its effect slightly. Avoid drinking large amounts of alcohol, as this can make erectile dysfunction worse and increase the risk of dizziness or low blood pressure [4]. Grapefruit juice can raise tadalafil levels in the blood, so it is best to avoid it while using this medicine.

Common side effects of tadalafil include headache, indigestion, back pain, muscle aches, flushing, and a blocked or runny nose [4]. These are usually mild and temporary. If you experience chest pain during or after sex, stop and seek urgent medical help. If you have an erection lasting more than four hours (priapism), or sudden loss of vision or hearing, go to A&E immediately. Continue taking infliximab and any other prescribed medicines as normal unless your doctor advises otherwise.

When to get urgent help

• Erection lasting more than 4 hours (priapism)—go to A&E immediately to prevent permanent damage
• Sudden loss of vision in one or both eyes—stop tadalafil and seek urgent medical help
• Sudden decrease or loss of hearing, sometimes with ringing in the ears or dizziness—stop and see a doctor urgently
• Chest pain during or after sexual activity—stop, do not take more tadalafil, and call 999 if pain does not resolve quickly
• Severe allergic reaction (rash, swelling of face or throat, difficulty breathing)—call 999

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

Other ED Treatment Options Available at Cured Pharmacy

Tadalafil is one of several effective ED treatments available. Sildenafil (generic Viagra) is another PDE5 inhibitor that works in a similar way but has a shorter duration of action—around four to six hours [3]. It is taken about one hour before sex and is available in 25mg, 50mg, and 100mg strengths. Vardenafil (generic Levitra) and avanafil (Spedra) are also PDE5 inhibitors, with avanafil working particularly quickly (as soon as 15–30 minutes) [6][11].

All PDE5 inhibitors work by the same mechanism and have similar interactions and contraindications, so the same safety checks apply whether you choose tadalafil, sildenafil, vardenafil, or avanafil [2]. Your prescriber can help you decide which medicine and dose are best suited to your needs and lifestyle. Some men prefer the longer action of tadalafil, while others prefer the shorter, more predictable window of sildenafil.

If oral ED medicines are not suitable or effective for you, other options include Vitaros (alprostadil cream applied to the tip of the penis) or Caverject (alprostadil injection), both of which are prescription-only [7]. Eroxon is a topical gel medical device available without prescription. Your GP or a specialist can also refer you for further assessment if needed. Cured Pharmacy offers a confidential, UK-registered prescriber-led online consultation for all prescription ED treatments, with discreet home delivery.

When to See Your GP About Erectile Dysfunction

If you are experiencing erectile dysfunction for the first time, it is important to see your GP for a check-up. 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 blood tests, check your cardiovascular health, and review any medicines that might be contributing to the problem. Treating the underlying cause—and optimising management of conditions like inflammatory bowel disease or arthritis—can sometimes improve ED as well.

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