Tadalafil and Solifenacin: Can You Take Them Together?

Tadalafil and Solifenacin: Understanding the Interaction

Published: 26 October 2026

Many men wonder whether tadalafil and solifenacin can be taken together safely. Tadalafil is a medicine used to treat erectile dysfunction (ED), while solifenacin is prescribed for overactive bladder symptoms. The good news is that no major direct interaction is commonly reported between these two medicines, but your prescriber will still need to check your individual circumstances carefully. This page explains what each medicine does, how they may affect each other, and what you need to know to use them safely.

What Is Tadalafil and How Does It Work?

Tadalafil is a medicine used 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 [4]. Tadalafil is the active ingredient in branded Cialis and is also available as a generic medicine.

Tadalafil comes in two main 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 tablets (2.5mg or 5mg) taken once a day at the same time [4]. Unlike some other ED treatments, tadalafil's long duration means you don't need to time it as precisely before sex. However, it still requires sexual stimulation to work—it won't cause an erection on its own.

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. Tadalafil is only available on prescription in the UK after a clinical assessment by a qualified prescriber, who will check your medical history and current medicines to ensure it is safe for you.

What Is Solifenacin and Why Is It Prescribed?

Solifenacin is a medicine used to treat symptoms of an overactive bladder, such as a sudden urgent need to urinate, needing to urinate frequently, or urinary incontinence (leaking) [12]. It belongs to a class of medicines called antimuscarinics (or anticholinergics), which work by relaxing the bladder muscle, reducing the urge to urinate and helping the bladder hold more urine.

Solifenacin is usually taken once a day as a 5mg or 10mg tablet. Common side effects include dry mouth, constipation, blurred vision, indigestion, and feeling tired [12]. Because it works by blocking certain nerve signals, it can also cause dizziness or drowsiness in some people. Solifenacin is a prescription-only medicine, and your doctor will have considered your symptoms and medical history before prescribing it.

Overactive bladder and erectile dysfunction can sometimes occur together, particularly in older men or those with conditions such as diabetes or prostate problems. This means it's not uncommon for men to be prescribed both solifenacin for bladder symptoms and tadalafil for ED. Understanding how these medicines interact is important for your safety and treatment success.

Why Men May Need Both Medicines

Lower urinary tract symptoms (including overactive bladder) and erectile dysfunction often share common underlying causes, such as reduced blood flow, nerve damage, or age-related changes [2]. Conditions like diabetes, high blood pressure, and obesity can affect both bladder function and erectile function. Some men also experience bladder symptoms as a side effect of prostate enlargement, which can coexist with ED. This overlap means that treating both conditions with separate medicines—such as solifenacin for the bladder and tadalafil for erections—is a realistic and sometimes necessary approach to improving quality of life.

Do Tadalafil and Solifenacin Interact?

No major direct interaction between tadalafil and solifenacin is commonly reported in standard drug interaction databases or prescribing guidance [3][4][12]. This means that, in general, these two medicines can be taken together without one significantly affecting how the other works or causing a dangerous reaction. However, this does not mean the combination is automatically safe for everyone—individual factors such as your overall health, blood pressure, other medicines, and medical history all play a role.

Both medicines can cause side effects that may overlap or add together. For example, solifenacin can occasionally cause dizziness or a drop in blood pressure when standing up, and tadalafil can also lower blood pressure slightly [4][12]. If you experience dizziness, lightheadedness, or fainting when taking both medicines, you should speak to your doctor or pharmacist. It's also important to note that solifenacin is partly broken down in the body by an enzyme called CYP3A4, and tadalafil is also metabolised by the same enzyme [4][12]. In most cases this does not cause a problem, but if you are taking other medicines that strongly affect this enzyme, your prescriber will need to review the combination carefully.

Your prescriber will check your full medication list during your consultation to ensure that tadalafil is safe to take alongside solifenacin and any other medicines you use. Never start, stop, or change the dose of any prescribed medicine without professional advice, even if you read that there is no interaction. Individual circumstances vary, and only a qualified healthcare professional can assess your specific situation.

What Your Prescriber Checks Before Approving Tadalafil and Solifenacin

When you request tadalafil through an online consultation at Cured Pharmacy, a UK-registered prescriber will review your medical history and current medicines, including solifenacin. They will check for any conditions or medicines that make tadalafil unsafe, such as recent heart attack or stroke, severe heart failure, very low blood pressure, or use of nitrates, nicorandil, riociguat, or recreational drugs called poppers [3][4]. These combinations can cause a dangerous drop in blood pressure and must be avoided.

Your prescriber will also check whether you are taking any alpha-blockers (such as tamsulosin, doxazosin, or alfuzosin) for prostate or blood pressure problems, as these can interact with tadalafil and increase the risk of dizziness or fainting [4]. If you are on an alpha-blocker, you will usually be started on the lowest dose of tadalafil, and you should be stable on the alpha-blocker before starting ED treatment. Other blood pressure medicines, antifungals, antibiotics, HIV medicines, and epilepsy treatments can also affect how tadalafil works or how much stays in your body [4].

Because solifenacin can cause dry mouth, constipation, and occasionally urinary retention (difficulty passing urine), your prescriber will want to know if you have any bladder or bowel problems, glaucoma, or kidney or liver disease [12]. They will also ask about your cardiovascular health, as sexual activity itself can put strain on the heart. This thorough review ensures that both medicines are suitable for you and that any risks are identified and managed.

Declaring All Your Medicines

It is essential to list every medicine you take during your consultation, including prescription medicines, over-the-counter treatments, herbal remedies, vitamins, and supplements. Even medicines that seem unrelated to ED or bladder symptoms can interact with tadalafil or solifenacin. For example, St John's wort (a herbal remedy for low mood) can reduce the effectiveness of tadalafil, and some antifungal or antibiotic medicines can increase tadalafil levels in your blood [4]. Your prescriber cannot assess safety accurately without a complete medication list, so always be thorough and honest in your answers.

Practical Advice for Taking Tadalafil and Solifenacin Together

If your prescriber approves tadalafil alongside solifenacin, take each medicine exactly as directed. Solifenacin is usually taken once a day at the same time, with or without food, and swallowed whole with water [12]. Tadalafil on-demand tablets (10mg or 20mg) should be taken at least 30 minutes before sexual activity, while daily tadalafil (2.5mg or 5mg) is taken once a day at the same time [4]. Do not take more than one dose of tadalafil in 24 hours, and do not adjust the dose of either medicine without consulting your prescriber.

Be aware of side effects from both medicines. Common side effects of tadalafil include headache, indigestion, back pain, muscle aches, and flushing [4]. Solifenacin commonly causes dry mouth, constipation, and blurred vision [12]. If you experience dizziness, lightheadedness, or feel faint—especially when standing up—sit or lie down and tell your doctor, as this may indicate low blood pressure. Drinking plenty of water can help with dry mouth from solifenacin, and avoiding heavy alcohol can reduce the risk of dizziness and improve the effectiveness of tadalafil.

Avoid grapefruit juice while taking tadalafil, as it can increase the amount of tadalafil in your blood and raise the risk of side effects [4]. If you develop any new symptoms, such as chest pain during sex, an erection lasting more than four hours, sudden loss of vision or hearing, or severe dizziness, seek urgent medical help. Always store both medicines in a cool, dry place out of reach of children, and check the expiry dates regularly.

When to Seek Medical Advice About Tadalafil and Solifenacin

You should contact your GP or pharmacist if you experience side effects that are troublesome or do not go away, such as persistent headache, severe indigestion, ongoing dizziness, or difficulty passing urine. If you notice that your erectile dysfunction is getting worse despite treatment, or if your overactive bladder symptoms are not improving with solifenacin, your doctor may need to review your treatment plan. Do not simply increase the dose of either medicine yourself, as this can be unsafe.

Seek urgent medical help (call 999 or go to A&E) if you experience chest pain or discomfort during or after sex, as this could be a sign of a heart problem [1][4]. An erection that lasts longer than four hours (priapism) is a medical emergency and requires immediate treatment to prevent permanent damage to the penis [4]. Sudden loss of vision in one or both eyes, or sudden decrease or loss of hearing (sometimes with ringing in the ears or dizziness), are rare but serious side effects that need urgent attention [4].

If you are prescribed a new medicine by another doctor or buy an over-the-counter treatment, always check with your pharmacist whether it is safe to take alongside tadalafil and solifenacin. Some medicines, such as certain antibiotics, antifungals, or treatments for HIV, can interact with tadalafil [4]. Never take nitrates (such as GTN spray or isosorbide mononitrate), nicorandil, riociguat, or recreational drugs called poppers while using tadalafil, as the combination can cause a life-threatening drop in blood pressure [3][4]. If you are unsure about any aspect of your treatment, speak to a healthcare professional—never guess or rely solely on internet forums.

Reviewing Your Treatment Regularly

Both erectile dysfunction and overactive bladder can change over time, and your treatment may need adjusting. Your GP or specialist should review your medicines at least once a year, or sooner if your symptoms change or you develop new health conditions [2]. If you find that tadalafil is not working as well as it used to, or if solifenacin is causing side effects that affect your quality of life, discuss alternatives with your doctor. There are other ED treatments (such as sildenafil, vardenafil, or avanafil) and other bladder medicines (such as mirabegron or other antimuscarinics) that may suit you better. Regular reviews help ensure you are on the most effective and safest treatment for your individual needs.

Scientific References

1. NHS. (n.d.). Erectile dysfunction (impotence). NHS website. https://www.nhs.uk/conditions/erection-problems-erectile-dysfunction/ [accessed 26 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 26 October 2026]
3. Joint Formulary Committee. (n.d.). Sildenafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/sildenafil/ [accessed 26 October 2026]
4. Joint Formulary Committee. (n.d.). Tadalafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/tadalafil/ [accessed 26 October 2026]
5. Electronic Medicines Compendium. (n.d.). Summaries of Product Characteristics and Patient Information Leaflets. https://www.medicines.org.uk/emc/ [accessed 26 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.