Tadalafil and Lansoprazole: Can You Take Them Together?

Tadalafil and Lansoprazole: Understanding the Interaction

Published: 22 October 2026

Many men taking tadalafil and lansoprazole together wonder whether this combination is safe. The good news is that no major interaction is commonly reported between tadalafil (a PDE5 inhibitor used for erectile dysfunction) and lansoprazole (a proton pump inhibitor used to reduce stomach acid). However, every medicine you take must be declared during your consultation so your prescriber can review your full medication list and ensure the combination is appropriate for you.

What is tadalafil and how does it work?

Tadalafil is the generic name for Cialis, a medicine licensed in the UK to treat erectile dysfunction (ED). It belongs to a group of medicines called PDE5 inhibitors, which work by relaxing the blood vessels in the penis, allowing more blood to flow in when you are sexually aroused [4].

Tadalafil is available in two forms: on-demand tablets (10 mg or 20 mg taken at least 30 minutes before sex, with effects lasting up to 36 hours) and daily tablets (2.5 mg or 5 mg taken once a day). Both require sexual stimulation to work—tadalafil will not cause an erection on its own [4].

At Cured Pharmacy, tadalafil is a prescription-only medicine supplied after an online consultation reviewed by a UK-registered prescriber. The prescriber will check your medical history, current medicines, and overall health to ensure tadalafil is safe and suitable for you.

What is lansoprazole and why is it prescribed?

Lansoprazole is a proton pump inhibitor (PPI) commonly prescribed to reduce stomach acid. It is used to treat conditions such as gastro-oesophageal reflux disease (GERD), stomach ulcers, and indigestion. Lansoprazole works by blocking the enzyme in the stomach wall that produces acid, helping to relieve symptoms like heartburn and acid reflux.

Many people take lansoprazole long-term to manage chronic digestive conditions. It is usually taken once a day, often in the morning before food. Lansoprazole is available on prescription and can also be purchased over the counter at lower doses for short-term use.

Because lansoprazole is so widely used, it is common for men taking tadalafil for erectile dysfunction to also be on lansoprazole for stomach-related issues. Understanding how these medicines interact is important for safe and effective treatment.

Common reasons for taking lansoprazole

Lansoprazole is prescribed for gastro-oesophageal reflux disease (GERD), peptic ulcers, and to protect the stomach lining in people taking non-steroidal anti-inflammatory drugs (NSAIDs) long-term. It is also used as part of treatment to eradicate Helicobacter pylori, a bacterium that can cause stomach ulcers.

Is there an interaction between tadalafil and lansoprazole?

No major interaction is commonly reported between tadalafil and lansoprazole. Lansoprazole does not significantly affect the way tadalafil is broken down in the body, and tadalafil does not interfere with the acid-reducing action of lansoprazole. This means the two medicines can usually be taken together without dose adjustments.

However, it is essential to declare all medicines—including over-the-counter and herbal products—during your consultation. Your prescriber will review your full medication list to check for any other medicines that might interact with tadalafil. Some medicines, such as nitrates, nicorandil, riociguat, and potent CYP3A4 inhibitors, can cause serious interactions with tadalafil [4].

Even though tadalafil and lansoprazole do not interact in a clinically significant way, your prescriber will still consider your overall health, including any heart conditions, blood pressure issues, or other factors that might affect whether tadalafil is safe for you.

How tadalafil is metabolised in the body

Tadalafil is broken down mainly by an enzyme called CYP3A4 in the liver. Lansoprazole does not strongly inhibit or induce this enzyme, which is why the two medicines do not significantly interact. Medicines that do affect CYP3A4—such as ketoconazole, ritonavir, or St John's wort—can raise or lower tadalafil levels and require dose adjustments or avoidance [4].

What your prescriber checks before approving tadalafil and lansoprazole together

During your online consultation at Cured Pharmacy, the prescriber will ask about all your current medicines, including lansoprazole, to ensure there are no contraindications. They will check for medicines that must not be taken with tadalafil, such as nitrates (GTN spray, isosorbide mononitrate), nicorandil, riociguat, or recreational drugs like poppers (amyl nitrites) [4].

The prescriber will also review any other blood-pressure-lowering medicines you take, such as alpha-blockers (e.g. tamsulosin, doxazosin) or antihypertensives. These can add to the blood-pressure-lowering effect of tadalafil, increasing the risk of dizziness or fainting. If you are on an alpha-blocker, you may be started on a lower dose of tadalafil [4].

Your cardiovascular health is another key consideration. Tadalafil is not suitable if you have had a recent heart attack or stroke, unstable angina, severe heart failure, or very low blood pressure. The prescriber will also ask about any history of sudden vision loss (NAION) or inherited retinal disorders, as these are contraindications to PDE5 inhibitors [4].

Practical advice for taking tadalafil and lansoprazole safely

If you are prescribed tadalafil while taking lansoprazole, follow the dosing instructions for both medicines carefully. Lansoprazole is usually taken once a day in the morning, at least 30 minutes before food. Tadalafil on-demand tablets should be taken at least 30 minutes before sexual activity, while daily tadalafil is taken once a day at the same time each day [4].

Avoid drinking large amounts of alcohol when taking tadalafil, as alcohol can worsen erectile dysfunction and add to the blood-pressure-lowering effect, increasing the risk of dizziness. Grapefruit juice can raise tadalafil levels in the blood and should be avoided [4].

Do not take more than one dose of tadalafil in 24 hours, and never take tadalafil with another PDE5 inhibitor (such as sildenafil or vardenafil) or with nitrates, nicorandil, riociguat, or poppers. If you experience side effects such as severe headache, dizziness, chest pain, or an erection lasting more than four hours, seek urgent medical help [4].

When to contact your GP or pharmacist

Contact your GP or pharmacist if you start a new medicine while taking tadalafil, or if you experience persistent side effects such as indigestion, back pain, or muscle aches. If you develop chest pain during sex, stop and seek urgent medical advice. Do not stop or change your prescribed medicines without consulting a healthcare professional.

Other medicines that can interact with tadalafil

While tadalafil and lansoprazole can be taken together, other medicines require caution or are contraindicated. Never take tadalafil with nitrates (used for angina), nicorandil, riociguat (for pulmonary hypertension), or poppers, as the combination can cause a dangerous drop in blood pressure [4].

Potent CYP3A4 inhibitors—such as ritonavir, cobicistat (in some HIV medicines), ketoconazole, itraconazole, and clarithromycin—can significantly raise tadalafil levels. If you are taking any of these, your prescriber may reduce the maximum dose of tadalafil or advise against it [4].

CYP3A4 inducers, such as rifampicin, carbamazepine, phenytoin, and St John's wort, can make tadalafil less effective by speeding up its breakdown in the body. Alpha-blockers (e.g. tamsulosin, doxazosin) can add to the blood-pressure-lowering effect of tadalafil, so you should be stable on the alpha-blocker and start on the lowest dose of tadalafil [4]. Always declare every medicine during your consultation so the prescriber can check for interactions.

Scientific References

1. NHS. (n.d.). Erectile dysfunction (impotence). NHS website. https://www.nhs.uk/conditions/erection-problems-erectile-dysfunction/ [accessed 22 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 22 October 2026]
3. Joint Formulary Committee. (n.d.). Tadalafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/tadalafil/ [accessed 22 October 2026]
4. Electronic Medicines Compendium. (n.d.). Summaries of Product Characteristics and Patient Information Leaflets. https://www.medicines.org.uk/emc/ [accessed 22 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.