Tadalafil and Dapagliflozin: Can You Take Them Together?

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Tadalafil and Dapagliflozin: Understanding the Interaction

Published: 19 October 2026

Many men wonder whether tadalafil and dapagliflozin can be taken together safely. The good news is that no major direct interaction is commonly reported between tadalafil (a medicine for erectile dysfunction) and dapagliflozin (a diabetes medicine), but your prescriber will still check your overall health and blood pressure before prescribing. This page explains what each medicine does, how they may affect each other, and what safety checks are needed.

What is tadalafil and what does it do?

Tadalafil is the generic name for Cialis, a medicine used to treat erectile dysfunction (ED) in men [4]. 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. Tadalafil does not cause an erection on its own—sexual stimulation is still needed.

Tadalafil is available in two ways: on-demand tablets (usually 10 mg or 20 mg) taken at least 30 minutes before sex, with effects lasting up to 36 hours, or daily low-dose tablets (2.5 mg or 5 mg) taken every day [4]. The long duration of action is why tadalafil is sometimes called the 'weekend pill'. At Cured Pharmacy, tadalafil is available from £7.95 after an online consultation with a UK prescriber.

Because tadalafil lowers blood pressure slightly as part of how it works, it is important that your prescriber checks your current medicines and overall cardiovascular health before prescribing it [4]. This is especially important if you take other medicines that affect blood pressure or blood sugar.

What is dapagliflozin and why is it prescribed?

Dapagliflozin is a medicine used to treat type 2 diabetes, heart failure, and chronic kidney disease. It is sold under the brand name Forxiga in the UK. Dapagliflozin belongs to a class of medicines called SGLT2 inhibitors, which work by helping your kidneys remove excess glucose (sugar) from your blood through your urine.

By lowering blood sugar levels, dapagliflozin helps improve diabetes control and can also reduce the risk of heart and kidney complications. It is usually taken once a day as a tablet, with or without food. Common side effects include urinary tract infections and increased urination, because the medicine works through the kidneys.

Dapagliflozin can sometimes cause a small drop in blood pressure, particularly when you first start taking it or if you are also taking other blood-pressure-lowering medicines. This is relevant when considering whether it is safe to take alongside tadalafil, which also has a mild blood-pressure-lowering effect.

Can you take tadalafil and dapagliflozin together?

Yes, tadalafil and dapagliflozin can usually be taken together. No major direct drug interaction is commonly reported between these two medicines. However, because both can lower blood pressure slightly, your prescriber will check your blood pressure and overall cardiovascular health during your consultation to make sure the combination is safe for you [4].

Men with type 2 diabetes are more likely to experience erectile dysfunction than men without diabetes, so it is quite common for someone taking dapagliflozin to also need treatment for ED [1][2]. The prescriber will review your full medication list, including dapagliflozin, and assess whether tadalafil is suitable based on your individual circumstances.

It is important to declare all your current medicines—including dapagliflozin—during your online consultation at Cured Pharmacy. The prescriber will consider factors such as your blood pressure, kidney function, and any other health conditions before approving tadalafil. Never start or stop a prescribed medicine without speaking to your GP or pharmacist first.

How the combination is assessed

During your consultation, the prescriber will ask about your blood pressure readings, any symptoms of dizziness or fainting, and whether your diabetes is well controlled. If your blood pressure is already on the lower side, or if you take other medicines that lower blood pressure (such as ACE inhibitors, angiotensin receptor blockers, or diuretics), the prescriber may start you on a lower dose of tadalafil or advise extra caution. The goal is to ensure that the combined blood-pressure-lowering effect does not cause symptoms such as dizziness, light-headedness, or fainting, especially when standing up quickly.

What your prescriber checks before approving tadalafil

Before prescribing tadalafil, the prescriber will review your medical history and current medicines to ensure it is safe for you [2][4]. Key checks include your cardiovascular health (heart and blood vessels), blood pressure, and whether you take any medicines that could interact dangerously with tadalafil. You must never take tadalafil if you use nitrates (such as GTN spray or isosorbide mononitrate), nicorandil, riociguat, or recreational drugs called 'poppers', because the combination can cause a dangerous drop in blood pressure.

The prescriber will also ask about any history of heart attack, stroke, severe heart failure, very low blood pressure, or conditions affecting your eyes (such as non-arteritic anterior ischaemic optic neuropathy, or NAION). If you take alpha-blockers for prostate symptoms (such as tamsulosin or doxazosin), the prescriber will ensure you are stable on that medicine and may start you on the lowest dose of tadalafil to reduce the risk of dizziness [4].

For men taking dapagliflozin, the prescriber will pay particular attention to blood pressure and kidney function, as both medicines can affect these. If you have any concerns or questions during your consultation, the prescriber or pharmacist at Cured Pharmacy is there to help.

Practical advice when taking tadalafil and dapagliflozin

If you are prescribed tadalafil while taking dapagliflozin, take each medicine exactly as directed. Tadalafil on-demand tablets (10 mg or 20 mg) should be taken at least 30 minutes before sexual activity, and the effect can last up to 36 hours [4]. Daily tadalafil (2.5 mg or 5 mg) is taken once a day at the same time, regardless of when you plan to have sex. Dapagliflozin is usually taken once daily in the morning.

Be aware of how you feel when you stand up, especially in the first few days of taking tadalafil. Both medicines can lower blood pressure, so you may feel dizzy or light-headed if you stand up too quickly. Sit or lie down if you feel faint, and let your GP or pharmacist know if this happens regularly. Drinking plenty of water is important when taking dapagliflozin, as it increases urination; avoid heavy alcohol, which can worsen ED and add to the blood-pressure-lowering effect [1].

Keep your diabetes well controlled, as high blood sugar over time can damage blood vessels and nerves, making ED worse [2]. Regular check-ups with your GP or diabetes nurse, a healthy diet, regular exercise, and not smoking all support both your diabetes management and erectile function.

Monitoring and follow-up

Your GP or diabetes team will monitor your HbA1c (a measure of long-term blood sugar control), kidney function, and blood pressure regularly while you take dapagliflozin. If you notice any new symptoms after starting tadalafil—such as persistent dizziness, chest pain during sex, or any sudden changes in vision or hearing—stop taking tadalafil and seek medical advice promptly. You can contact Cured Pharmacy or your GP for guidance at any time.

Warning signs and when to seek urgent help

While tadalafil and dapagliflozin are generally well tolerated together, it is important to know the warning signs that need urgent medical attention. If you experience chest pain or discomfort during or after sex, do not take another dose of tadalafil and seek medical help immediately—call 999 if the pain is severe or does not go away quickly [1][4].

An erection lasting more than four hours (called priapism) is a medical emergency and requires immediate treatment to prevent permanent damage to the penis. Go to A&E straight away 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), are rare but serious side effects of PDE5 inhibitors; stop taking tadalafil and seek urgent medical advice [4].

If you develop symptoms of diabetic ketoacidosis while taking dapagliflozin—such as feeling very thirsty, being sick, breathing more quickly than usual, or breath that smells fruity—contact your GP or call 111 immediately, as this is a rare but serious side effect of SGLT2 inhibitors. Always keep your prescriber informed of any new symptoms or concerns.

When to contact your GP or pharmacist

You should also contact your GP or pharmacist (non-urgently) if you experience persistent dizziness, fainting, or light-headedness, especially when standing up; recurrent urinary tract infections or genital infections (a known side effect of dapagliflozin); or if tadalafil does not seem to be working after trying it on several occasions. Your prescriber may need to adjust your dose or consider an alternative treatment. Cured Pharmacy's team is available to answer questions and provide advice as part of your ongoing care.

Scientific References

1. NHS. (n.d.). Erectile dysfunction (impotence). NHS website. https://www.nhs.uk/conditions/erection-problems-erectile-dysfunction/ [accessed 19 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 19 October 2026]
3. Joint Formulary Committee. (n.d.). Tadalafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/tadalafil/ [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.