Tadalafil and Finasteride: Can You Take Them Together?

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Tadalafil and Finasteride: Understanding the Interaction

Published: 21 October 2026

Many men wonder whether tadalafil and finasteride can be taken together safely. The good news is that no major interaction between these two medicines is commonly reported, and they are often prescribed together. Tadalafil is a PDE5 inhibitor used to treat erectile dysfunction (ED), while finasteride is a 5-alpha reductase inhibitor used for male pattern hair loss and benign prostatic hyperplasia (BPH). Understanding how each medicine works and what your prescriber checks can help you use both treatments safely and effectively.

What is tadalafil and how does it work?

Tadalafil is a prescription medicine used to treat erectile dysfunction 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 [3][4]. Tadalafil does not cause an erection on its own—sexual stimulation is still needed.

Tadalafil is available in two 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]. The longer duration of action is why tadalafil is sometimes called the 'weekend pill'. It is the generic version of Cialis and is available at Cured Pharmacy following an online consultation with a UK prescriber.

Common side effects include headache, indigestion, back pain, muscle aches, flushing, and nasal congestion [4]. These are usually mild and temporary. Tadalafil is not suitable for everyone, particularly men taking nitrates for chest pain, those with severe heart problems, or anyone who has experienced sudden vision loss in the past.

What is finasteride and how does it work?

Finasteride is a prescription medicine primarily used to treat male pattern hair loss (androgenetic alopecia) and benign prostatic hyperplasia (BPH), a non-cancerous enlargement of the prostate gland. It works by blocking an enzyme called 5-alpha reductase, which converts testosterone into dihydrotestosterone (DHT). DHT is a hormone that contributes to hair loss and prostate enlargement in some men.

For hair loss, finasteride is usually prescribed as a 1mg daily tablet. For BPH, the dose is typically 5mg once daily. The medicine can take several months to show noticeable effects on hair growth, and it needs to be taken continuously to maintain benefits. If you stop taking finasteride, any hair regrowth is usually lost within 12 months.

Finasteride can cause side effects in some men, including reduced libido, erectile dysfunction, ejaculation disorders, and breast tenderness or enlargement. These effects are uncommon and usually reversible when the medicine is stopped, though in rare cases sexual side effects may persist. It is important to discuss any concerns with your prescriber, who can review whether finasteride is the right choice for you.

Can you take tadalafil and finasteride together?

Yes, tadalafil and finasteride can generally be taken together. No major drug interaction between these two medicines is commonly reported in clinical practice or major drug databases. They work through completely different mechanisms in the body: tadalafil affects blood flow to the penis by inhibiting PDE5, while finasteride reduces DHT levels by blocking 5-alpha reductase. Because they do not share metabolic pathways or targets, they do not typically interfere with each other's effectiveness or safety.

In fact, some men are prescribed both medicines at the same time—tadalafil for erectile dysfunction and finasteride for hair loss or prostate symptoms. This combination is considered safe when prescribed and monitored by a healthcare professional. However, it is worth noting that finasteride itself can occasionally cause erectile dysfunction as a side effect in a small number of men. If you develop new or worsening ED after starting finasteride, it is important to discuss this with your prescriber.

During your online consultation at Cured Pharmacy, the prescriber will review all your current medicines, including finasteride, to ensure tadalafil is safe and appropriate for you. You should always declare every medicine you take, including over-the-counter products and supplements, so the prescriber can check for any potential issues. Never stop or change a prescribed medicine without professional advice.

What your prescriber checks

When you request tadalafil and are already taking finasteride, the prescriber will review your full medical history and current medicines. They will check that you do not have any contraindications to tadalafil, such as taking nitrates, nicorandil, riociguat, or having severe heart problems. They will also ask about any side effects you may be experiencing from finasteride, particularly sexual side effects, to ensure tadalafil is the right treatment.

The prescriber will confirm that your blood pressure is stable and that you are not taking other medicines that could interact with tadalafil, such as alpha-blockers or potent CYP3A4 inhibitors. They may also discuss whether your ED could be related to finasteride or other underlying health conditions, such as diabetes or cardiovascular disease, which should be managed by your GP [1][2].

Practical advice for taking tadalafil and finasteride

If you are taking both tadalafil and finasteride, you can take them at different times of the day or together—there is no need to separate the doses. For example, if you take finasteride once daily in the morning for hair loss, you can take on-demand tadalafil (10mg or 20mg) at least 30 minutes before sexual activity, or take daily tadalafil (2.5mg or 5mg) at any convenient time each day.

Keep track of any side effects from either medicine. If you notice new erectile difficulties after starting finasteride, do not assume tadalafil will automatically solve the problem—discuss this with your prescriber, as stopping or adjusting finasteride may be necessary. Similarly, if you experience common tadalafil side effects such as headache or indigestion, these are usually mild and may improve over time, but persistent or severe symptoms should be reported.

Avoid heavy alcohol when using tadalafil, as it can worsen erectile dysfunction and increase the risk of dizziness or low blood pressure. Grapefruit juice may raise tadalafil levels in the blood, so it is best to avoid it. Always store both medicines in a cool, dry place away from children, and check the expiry dates regularly.

When tadalafil and finasteride should not be used

While tadalafil and finasteride can be taken together, each medicine has its own contraindications. Tadalafil must not be taken if you are using nitrates (such as GTN spray, isosorbide mononitrate, or isosorbide dinitrate), nicorandil, riociguat, or recreational drugs called 'poppers' (amyl or alkyl nitrites). Combining tadalafil with any of these can cause a dangerous drop in blood pressure [3][4].

Tadalafil is also not suitable if you have had a recent heart attack or stroke, have unstable angina, severe heart failure, very low blood pressure, or a history of non-arteritic anterior ischaemic optic neuropathy (NAION), a rare condition causing sudden vision loss. Finasteride is contraindicated in women, children, and anyone with a known hypersensitivity to the medicine. It should not be handled by pregnant women, as it can harm a male foetus.

If you develop chest pain during sexual activity, stop and seek urgent medical help—do not take more tadalafil. If you experience an erection lasting more than four hours (priapism), sudden loss of vision or hearing, or severe dizziness, seek emergency medical attention immediately. These are rare but serious side effects that require prompt treatment.

Other medicines to mention

Always tell your prescriber about every medicine you take, including over-the-counter treatments, herbal remedies, and supplements. Alpha-blockers (such as tamsulosin, doxazosin, or alfuzosin), often used for prostate symptoms, can interact with tadalafil and cause low blood pressure or dizziness. If you take an alpha-blocker, you should be stable on it before starting tadalafil, and your prescriber will usually recommend the lowest dose of tadalafil initially.

Medicines that affect liver enzymes, such as ritonavir, cobicistat, ketoconazole, itraconazole, clarithromycin, rifampicin, carbamazepine, phenytoin, and St John's wort, can alter tadalafil levels in the blood. Your prescriber will check the summary of product characteristics (SmPC) if you take any of these and adjust the dose or advise against tadalafil if necessary [4][12]. Other blood-pressure medicines may add to the blood-pressure-lowering effect of tadalafil, which is usually manageable but must be reviewed.

Getting tadalafil and finasteride at Cured Pharmacy

Cured Pharmacy is a GPhC-registered online pharmacy (GPhC 9012511) offering a range of erectile dysfunction treatments, including tadalafil, following a confidential online consultation. The consultation is reviewed by a UK-registered prescriber, who will check your medical history, current medicines (including finasteride), and suitability for treatment. If approved, your medicine is dispensed by our pharmacy team and delivered discreetly to your door.

We offer several tadalafil options, including generic tadalafil tablets and branded Cialis. Prices start from £7.95 for generic tadalafil, with a first-order discount available using code Ednew (£6.36). All prescription medicines are only supplied after a clinical assessment, ensuring your safety and suitability for treatment. You can also access other PDE5 inhibitors such as sildenafil, vardenafil, and avanafil if tadalafil is not the best choice for you.

If you are experiencing erectile dysfunction for the first time, or if it is getting worse, it is important to see your GP. ED can be an early warning sign of underlying health conditions such as heart disease, diabetes, or high blood pressure [1][2]. Your GP can arrange tests, review your medicines, and refer you to a specialist if needed. Cured Pharmacy works alongside NHS services to provide convenient access to treatment once a diagnosis has been made.

Why choose Cured Pharmacy?

Cured Pharmacy combines the convenience of online ordering with the expertise of UK-registered pharmacists and prescribers. Every consultation is reviewed individually, and our team is available to answer questions about your treatment. We understand that discussing erectile dysfunction can feel uncomfortable, so we provide a discreet, non-judgemental service with plain packaging and confidential delivery.

All our medicines are sourced from licensed UK wholesalers and manufacturers, meeting the same quality standards as high-street pharmacies. We are regulated by the General Pharmaceutical Council and the Care Quality Commission, giving you confidence in the safety and legitimacy of your treatment. Whether you are taking finasteride for hair loss or prostate health, our prescribers will ensure tadalafil is safe and appropriate for you.

Scientific References

1. NHS. (n.d.). Erectile dysfunction (impotence). NHS website. https://www.nhs.uk/conditions/erection-problems-erectile-dysfunction/ [accessed 21 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 21 October 2026]
3. Joint Formulary Committee. (n.d.). Sildenafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/sildenafil/ [accessed 21 October 2026]
4. Joint Formulary Committee. (n.d.). Tadalafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/tadalafil/ [accessed 21 October 2026]
5. Electronic Medicines Compendium. (n.d.). Summaries of Product Characteristics and Patient Information Leaflets. https://www.medicines.org.uk/emc/ [accessed 21 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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