Tadalafil and Latanoprost: Can You Take Them Together?

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Tadalafil and Latanoprost: Understanding the Interaction

Published: 22 October 2026

Many men wonder whether tadalafil and latanoprost can be taken together safely. The good news is that no major interaction is commonly reported between tadalafil (a medicine for erectile dysfunction) and latanoprost (eye drops used to treat glaucoma and high pressure inside the eye). However, your prescriber will always review your full medication list during a consultation to ensure tadalafil is suitable for you personally.

What is tadalafil and latanoprost used for?

Tadalafil is a prescription 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 increased blood flow when you are sexually aroused [4]. Tadalafil is available as on-demand tablets (10mg or 20mg, taken at least 30 minutes before sex, with effects lasting up to 36 hours) or as a daily low-dose tablet (2.5mg or 5mg). It requires sexual stimulation to work and does not cause an automatic erection.

Latanoprost is a prescription eye drop used to treat glaucoma and ocular hypertension (raised pressure inside the eye). It works by increasing the drainage of fluid from the eye, which helps to lower the pressure and prevent damage to the optic nerve [12]. Latanoprost is usually applied once daily, typically in the evening. It is a prostaglandin analogue and works locally in the eye, with minimal absorption into the bloodstream.

Because latanoprost acts mainly in the eye and tadalafil works on blood vessels elsewhere in the body, the two medicines do not typically interfere with each other's action. However, every person's medical situation is unique, so a full assessment by a UK prescriber is essential before starting tadalafil.

Is there an interaction between tadalafil and latanoprost?

No major interaction between tadalafil and latanoprost is commonly reported in clinical practice or drug interaction databases. Latanoprost is applied directly to the eye and only a very small amount enters the bloodstream, so it does not usually affect how tadalafil works or increase the risk of side effects [12]. Similarly, tadalafil does not interfere with the pressure-lowering effect of latanoprost in the eye.

That said, tadalafil can cause a small, temporary drop in blood pressure, which is usually well tolerated. In rare cases, some people using tadalafil have reported changes in vision, such as blurred vision, increased sensitivity to light, or a blue tinge to vision [4]. These effects are thought to be related to tadalafil's mild action on another enzyme (PDE6) in the retina, rather than an interaction with latanoprost.

If you are using latanoprost for glaucoma or high eye pressure, it is important to tell your prescriber during your consultation. They will check your full medical history, including any eye conditions, to ensure tadalafil is safe for you. If you have a history of non-arteritic anterior ischaemic optic neuropathy (NAION, a rare cause of sudden vision loss), tadalafil may not be suitable [4].

What does your prescriber check before prescribing tadalafil?

When you request tadalafil through Cured Pharmacy's online consultation, a UK-registered prescriber will review your answers to ensure the medicine is safe and appropriate for you. They will ask about all your current medicines (including eye drops like latanoprost), any medical conditions (especially heart, liver, kidney or eye problems), and whether you have had any allergic reactions in the past [2][4].

Your prescriber will specifically check that you are not taking any medicines that must never be combined with tadalafil. These include nitrates (such as GTN spray, isosorbide mononitrate or dinitrate), nicorandil, riociguat, or amyl/alkyl nitrites (poppers). Taking tadalafil with any of these can cause a dangerous drop in blood pressure [4]. You must also not take tadalafil if you are already using another PDE5 inhibitor (such as sildenafil, vardenafil or avanafil).

If you take medicines for high blood pressure or an enlarged prostate (such as alpha-blockers like tamsulosin or doxazosin), your prescriber will ensure you are stable on that treatment and may recommend starting tadalafil at a lower dose to reduce the risk of dizziness [4]. They will also check for any medicines that can raise tadalafil levels in the blood (such as ritonavir, ketoconazole or clarithromycin), which may require a dose adjustment.

Declaring all your medicines

It is essential to list every medicine you take during your consultation, including prescription medicines, over-the-counter products, herbal remedies (such as St John's wort), and any eye drops or inhalers. Even if a medicine seems unrelated to erectile dysfunction, it may affect how tadalafil works or whether it is safe for you. Your prescriber cannot make a safe decision without a complete picture of your health and treatments.

Practical advice when using tadalafil and latanoprost together

If your prescriber approves tadalafil and you are already using latanoprost eye drops, you can continue using both medicines as directed. Apply your latanoprost eye drops at the usual time (typically once daily in the evening) and take your tadalafil tablet as prescribed (either on-demand before sexual activity or once daily, depending on the dose) [4][12].

There is no need to separate the timing of the two medicines, as they work in different parts of the body and do not interfere with each other. However, if you notice any new or unusual symptoms after starting tadalafil—such as dizziness, changes in your vision, or eye discomfort—contact your GP or pharmacist for advice. While these are unlikely to be caused by an interaction, they should always be checked.

Remember that tadalafil can cause mild, temporary visual disturbances in some people (such as blurred vision or increased sensitivity to light). These are usually short-lived and not harmful, but if you experience sudden loss of vision in one or both eyes, stop taking tadalafil immediately and seek urgent medical help, as this could be a sign of NAION [4]. Continue your latanoprost as normal unless your eye specialist advises otherwise.

Monitoring your eye health

If you have glaucoma or high eye pressure, you will already be under the care of an optometrist or ophthalmologist who monitors your condition regularly. Make sure they know you are taking tadalafil, especially if you have any concerns about your vision. Routine eye checks are important to ensure your glaucoma treatment is working well and to detect any changes early.

Other medicines and conditions to mention

While tadalafil and latanoprost do not interact, tadalafil can interact with several other medicines. Always tell your prescriber if you take any blood pressure medicines, as tadalafil can add to their blood-pressure-lowering effect and may cause dizziness, especially when you stand up [4]. This is usually manageable, but your prescriber needs to know.

If you take medicines that affect liver enzymes (such as rifampicin, carbamazepine, phenytoin, or St John's wort), they can reduce tadalafil levels in your blood and make it less effective. Conversely, potent CYP3A4 inhibitors (such as ritonavir, cobicistat, ketoconazole, itraconazole, or clarithromycin) can raise tadalafil levels, increasing the risk of side effects. Your prescriber will adjust your tadalafil dose if needed or choose a different ED treatment [4].

Tadalafil is not suitable if sexual activity is inadvisable for your heart (for example, if you have had a recent heart attack or stroke, unstable angina, or severe heart failure). It is also not recommended if you have very low blood pressure, severe liver or kidney problems, or certain inherited eye conditions affecting the retina [2][4]. Your prescriber will assess all these factors during your consultation.

When to seek help and what to watch for

Tadalafil is generally well tolerated, but like all medicines, it can cause side effects in some people. Common side effects include headache, indigestion, back pain, muscle aches, flushing, and a blocked or runny nose [4]. These are usually mild and go away on their own. If they are troublesome or persistent, speak to your pharmacist or prescriber.

Seek urgent medical help if you experience an erection lasting more than four hours (priapism), as this can damage the penis permanently if not treated quickly. You should also seek immediate help if you have sudden loss of vision or hearing, or chest pain during sex (stop sexual activity, do not take more tadalafil, and call 999 if the pain does not go away) [4].

If you develop new symptoms after starting tadalafil—such as severe dizziness, fainting, swelling of the face or throat, or difficulty breathing—stop taking the medicine and contact your GP or call 111 for advice. These could be signs of an allergic reaction or another serious problem. Continue using your latanoprost eye drops as prescribed unless your doctor tells you to stop.

Reporting side effects

If you experience any side effect that concerns you, even if it is not listed in the patient information leaflet, you can report it via the Yellow Card Scheme at yellowcard.mhra.gov.uk or by calling 0800 731 6789. Reporting helps improve the safety information available for all patients.

Scientific References

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

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