Sildenafil and Tofacitinib: Can They Be Taken Together?

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Sildenafil and Tofacitinib: Understanding the Interaction

Published: 18 October 2026

If you're considering sildenafil and tofacitinib together, you'll want to know whether this combination is safe. Sildenafil is a PDE5 inhibitor used to treat erectile dysfunction, while tofacitinib is an immunosuppressant medicine prescribed for conditions such as rheumatoid arthritis, psoriatic arthritis, and ulcerative colitis. Understanding how these medicines interact is essential for safe and effective treatment.

What Is Sildenafil and How Does It Work?

Sildenafil, commonly known by the brand name Viagra, is a prescription medicine used to treat erectile dysfunction (ED) in men [1]. It belongs to a class of medicines called phosphodiesterase type 5 (PDE5) inhibitors, which work by relaxing the blood vessels in the penis, allowing increased blood flow when you're sexually aroused [3].

Sildenafil is typically taken about one hour before sexual activity, with effects lasting around four to six hours [3]. It's available in doses of 25mg, 50mg, and 100mg, and should not be taken more than once a day. The medicine only works when you're sexually stimulated—it won't cause an erection on its own.

Common side effects include headache, flushing, indigestion, and nasal congestion [3]. More serious but rare side effects can include sudden vision or hearing loss, and prolonged erections lasting more than four hours (priapism), which require urgent medical attention. Sildenafil is not suitable for everyone, particularly those taking certain other medicines or with specific heart conditions.

What Is Tofacitinib and What Is It Used For?

Tofacitinib is a prescription medicine classified as a Janus kinase (JAK) inhibitor, used to treat inflammatory conditions such as rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, and ulcerative colitis [12]. It works by blocking specific enzymes in the immune system that contribute to inflammation and joint damage.

Unlike sildenafil, which is taken as needed for erectile dysfunction, tofacitinib is usually taken daily as a long-term treatment to manage chronic inflammatory conditions. It's available in tablet form, typically at doses of 5mg or 10mg, depending on the condition being treated and individual patient factors.

Tofacitinib can increase the risk of infections because it suppresses part of the immune system, and it may also affect blood counts and liver function. Regular blood tests are usually required when taking this medicine. Other potential side effects include headache, diarrhoea, and increased cholesterol levels. Because of its effects on the immune system and other body processes, tofacitinib can interact with various other medicines.

How Tofacitinib Affects the Body

Tofacitinib works inside cells to block JAK enzymes, which are involved in signalling pathways that control inflammation and immune responses. By inhibiting these enzymes, tofacitinib reduces the inflammation that causes symptoms in conditions like rheumatoid arthritis. This targeted approach can be very effective for managing chronic inflammatory diseases, but it also means the medicine needs careful monitoring and consideration of potential interactions with other treatments you may be taking.

Can You Take Sildenafil and Tofacitinib Together?

There is no major, well-documented interaction between sildenafil and tofacitinib reported in standard drug interaction databases [3][12]. This means that, in general, these two medicines are not known to directly interfere with each other's effectiveness or cause a dangerous reaction when taken together. However, this does not automatically mean the combination is suitable for everyone.

Every person's medical situation is unique, and the safety of combining any two medicines depends on your overall health, other conditions you have, and all the other medicines you're taking. Both sildenafil and tofacitinib can affect blood pressure and other body systems, so a healthcare professional needs to review your complete medical picture before confirming the combination is appropriate for you.

When you request sildenafil through Cured Pharmacy's online consultation, you'll be asked to list all your current medicines, including tofacitinib. A UK-registered prescriber will review this information alongside your health history to ensure sildenafil is safe and suitable for you. Never assume a combination is safe without professional advice, and never stop or change your prescribed tofacitinib without consulting the doctor who prescribed it.

What Your Prescriber Checks Before Approving Sildenafil and Tofacitinib

When assessing whether sildenafil is safe for someone taking tofacitinib, a prescriber will review several important factors. They'll check your cardiovascular health, as sildenafil can lower blood pressure and is not suitable if you have certain heart conditions, recent heart attack or stroke, or unstable angina [3]. They'll also review whether you're taking any medicines that are known to interact dangerously with sildenafil, such as nitrates, nicorandil, or riociguat.

Your prescriber will consider any other medicines you're taking alongside tofacitinib, as some can affect how sildenafil works in your body. For example, medicines that inhibit the liver enzyme CYP3A4 can increase sildenafil levels, potentially raising the risk of side effects [3]. Alpha-blockers used for prostate problems or high blood pressure can also interact with sildenafil, causing dizziness or fainting due to low blood pressure.

The prescriber will also assess your overall health status, including kidney and liver function, as these can affect how both medicines are processed in your body. If you have any history of eye problems, particularly a condition called non-arteritic anterior ischaemic optic neuropathy (NAION), or if you're taking medicines that might increase infection risk alongside tofacitinib, these factors will be carefully considered. This thorough review ensures that sildenafil is prescribed safely and at the right dose for your individual circumstances.

Starting Sildenafil While on Tofacitinib

If you're approved to take sildenafil while on tofacitinib, your prescriber will typically recommend starting with the lowest effective dose to see how you respond. For most men, this means starting with sildenafil 50mg, though a lower 25mg dose may be suggested if you have other risk factors or are taking medicines that could interact. You should take sildenafil about one hour before sexual activity, and remember that it requires sexual stimulation to work. Monitor how you feel, particularly for dizziness or any unusual symptoms, and report these to your healthcare provider.

Practical Advice for Taking Sildenafil and Tofacitinib Safely

If you've been prescribed both medicines, take each exactly as directed. Sildenafil should be taken about one hour before sexual activity, no more than once a day, while tofacitinib is usually taken daily at the same time each day as prescribed by your rheumatologist or gastroenterologist [3][12]. Don't adjust the dose or timing of either medicine without professional advice.

Be aware of how you feel when you first take sildenafil, particularly any dizziness, lightheadedness, or changes in vision. These could indicate low blood pressure or other side effects that need attention. Avoid drinking large amounts of alcohol when taking sildenafil, as alcohol can worsen erectile dysfunction and increase the risk of low blood pressure and dizziness [3]. Grapefruit juice should also be avoided, as it can increase sildenafil levels in your blood.

Keep all your healthcare providers informed about every medicine you're taking. Your rheumatologist or gastroenterologist should know you're using sildenafil, and the prescriber of your sildenafil needs to know about your tofacitinib and any other treatments. If you develop any new symptoms, infections, or side effects, or if you're prescribed any new medicines, check with a healthcare professional before continuing to take sildenafil. Store both medicines safely, away from heat and moisture, and keep them out of reach of children.

When to Seek Medical Advice About Sildenafil and Tofacitinib

Certain symptoms require urgent medical attention when taking sildenafil. If you experience an erection lasting more than four hours (priapism), seek immediate help by calling 999 or going to A&E, as this can cause permanent damage if not treated quickly [3]. Sudden loss of vision or hearing, chest pain during sexual activity, or severe dizziness or fainting also require emergency care.

Contact your GP or prescriber promptly if you notice any new or worsening side effects from either medicine, or if sildenafil stops working as well as it did initially. If you develop signs of infection while taking tofacitinib—such as fever, persistent sore throat, or unusual tiredness—contact your doctor, as tofacitinib can increase infection risk and you may need assessment before continuing other medicines [12].

If you're prescribed any new medicine by another healthcare provider, check whether it's safe to continue taking sildenafil. Some medicines, particularly nitrates for angina, are absolutely contraindicated with sildenafil and must never be taken together [3]. If you have any concerns or questions about taking sildenafil and tofacitinib together, speak to a pharmacist or your prescriber—never simply stop taking a prescribed medicine without professional advice, as this could affect your underlying condition.

Reporting Side Effects

If you experience any side effects from sildenafil or tofacitinib, you can report them through the UK Yellow Card Scheme at yellowcard.mhra.gov.uk or by searching for 'Yellow Card' in the Google Play or Apple App Store. Reporting side effects helps improve the safety information available about medicines and contributes to ongoing monitoring of their safety in real-world use.

Scientific References

1. NHS. (n.d.). Erectile dysfunction (impotence). NHS website. https://www.nhs.uk/conditions/erection-problems-erectile-dysfunction/ [accessed 18 October 2026]
2. Joint Formulary Committee. (n.d.). Sildenafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/sildenafil/ [accessed 18 October 2026]
3. Electronic Medicines Compendium. (n.d.). Summaries of Product Characteristics and Patient Information Leaflets. https://www.medicines.org.uk/emc/ [accessed 18 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.