Tadalafil and Isotretinoin: Can You Take Them Together?

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At a glance

What is tadalafil and how does it work?

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 the blood vessels in the penis, allowing increased blood flow when you are sexually aroused [4].

Tadalafil is available as the branded medicine Cialis or as generic tadalafil. It can be taken on-demand (10mg or 20mg at least 30 minutes before sexual activity, with effects lasting up to 36 hours) or as a daily low dose (2.5mg or 5mg) [4]. Unlike some other ED treatments, tadalafil's long duration of action means you don't need to time it as precisely before sex.

It's important to understand that tadalafil only works when you are sexually stimulated – it does not cause an automatic erection. The medicine helps your body respond naturally to arousal by improving blood flow to the penis [4].

What is isotretinoin and why is it prescribed?

Isotretinoin (often known by the brand name Roaccutane) is a powerful prescription medicine used to treat severe acne that has not responded to other treatments, including antibiotics. It belongs to a group of medicines called retinoids, which are related to vitamin A [12].

Isotretinoin works by reducing the amount of oil (sebum) produced by your skin's oil glands, helping to renew your skin more quickly and reducing inflammation. Treatment typically lasts several months and requires careful monitoring by a dermatologist because of potential side effects [12].

The medicine is known for causing dryness of the skin, lips and eyes, and has important restrictions – particularly for women of childbearing age due to serious risks to an unborn baby. Men taking isotretinoin must also follow specific precautions, and your dermatologist will discuss these with you before starting treatment [12].

Common side effects of isotretinoin

Most people taking isotretinoin experience dry skin and lips, and may notice dry eyes, nosebleeds, or joint and muscle aches. Some people report mood changes or feel more tired than usual. These side effects are usually manageable with moisturisers, lip balm and eye drops, but you should always report any concerns to your dermatologist [12].

Is there a direct interaction between tadalafil and isotretinoin?

No major direct pharmacological interaction is commonly reported between tadalafil and isotretinoin. These two medicines work through different mechanisms in the body: tadalafil affects blood flow by inhibiting the PDE5 enzyme, while isotretinoin affects skin oil production and cell turnover [4][12].

However, 'no major interaction' does not automatically mean the combination is suitable for everyone. Your prescriber will still need to review your complete medical history, all current medications (including isotretinoin), and any underlying health conditions during your consultation. This careful assessment ensures that tadalafil is safe and appropriate for you specifically [2].

It's worth noting that isotretinoin can occasionally cause headaches, and tadalafil may also cause headaches as a side effect in some men. If you experience persistent or severe headaches while taking both medicines, contact your GP or prescriber for advice [4][12].

What you need to know

• No major direct interaction is commonly reported between tadalafil and isotretinoin
• Your prescriber reviews all your medicines during consultation to ensure safety
• Never take tadalafil with nitrates, nicorandil, riociguat or poppers
• Declare every medicine you take, including acne treatments and supplements
• Seek urgent help for erections lasting over four hours or sudden vision loss

What does your prescriber check before prescribing tadalafil with isotretinoin?

When you request tadalafil treatment through Cured Pharmacy, a UK-registered prescriber reviews your online consultation answers carefully. They will check your full medication list, including isotretinoin, to identify any potential interactions or contraindications [2].

The prescriber will assess your cardiovascular health, blood pressure, and whether you have any conditions that make sexual activity inadvisable – such as recent heart attack or stroke, unstable angina, or severe heart failure. They will also check that you are not taking any medicines that must never be combined with tadalafil, including nitrates (GTN spray, isosorbide mononitrate), nicorandil, riociguat, or recreational drugs called 'poppers' [3][4].

If you take other medicines that can affect blood pressure – such as alpha-blockers for prostate symptoms (tamsulosin, doxazosin) or certain antifungals and antibiotics – your prescriber will consider whether tadalafil is safe and may adjust the dose. You should declare every medicine you take, including over-the-counter products and supplements, to ensure a thorough safety check [4].

Why you must declare all your medicines

Even medicines that seem unrelated to ED can interact with tadalafil. For example, some antibiotics and antifungals can increase tadalafil levels in your blood, raising the risk of side effects. Grapefruit juice can have a similar effect. Being completely honest about what you take – including herbal remedies like St John's wort – helps your prescriber keep you safe [4].

Practical advice for taking tadalafil and isotretinoin together

If your prescriber approves tadalafil treatment while you are taking isotretinoin, follow the dosing instructions for each medicine carefully. Take tadalafil as directed – either on-demand (at least 30 minutes before sexual activity) or daily, depending on which regimen your prescriber recommends [4].

Continue your isotretinoin treatment exactly as your dermatologist has prescribed. Do not stop or change the dose of either medicine without speaking to the relevant prescriber first. If you experience any new or worsening symptoms after starting tadalafil, contact your GP or the prescribing pharmacist for advice [12].

Stay well hydrated, especially because isotretinoin can cause dryness throughout your body. Limit alcohol intake, as heavy drinking can worsen erectile dysfunction and add to the blood-pressure-lowering effects of tadalafil, increasing the risk of dizziness [1][4]. If you develop a persistent headache, dizziness, or any other side effect that concerns you, seek medical advice promptly.

When to get urgent help

• Erection lasting more than 4 hours – call 999 or go to A&E immediately
• Sudden loss of vision or hearing – seek emergency medical help
• Chest pain during sexual activity – stop and call 999
• Severe depression or thoughts of self-harm while on isotretinoin – contact your GP or dermatologist urgently
• Severe persistent headache or dizziness – seek same-day medical advice

Call 999 or go to A&E in an emergency, or contact NHS 111 for urgent advice.

When to seek urgent help and ongoing monitoring

While tadalafil is generally well tolerated, you should seek urgent medical help if you experience an erection lasting more than four hours (priapism), sudden loss of vision or hearing, or chest pain during sexual activity. Call 999 or go to A&E immediately if any of these occur [4].

If you notice mood changes, severe depression, or thoughts of self-harm while taking isotretinoin, contact your GP or dermatologist urgently. Although rare, isotretinoin has been associated with mood disturbances, and these must be taken seriously [12].

Regular follow-up is important when you are on isotretinoin, as your dermatologist will monitor your progress and check for side effects through blood tests and consultations. If your health changes in any way – for example, if you are prescribed a new medicine or develop a new condition – inform both your dermatologist and the prescriber of your ED treatment. At Cured Pharmacy, prescription treatments are only supplied after an online consultation reviewed by a UK-registered prescriber, ensuring your safety at every step [2].

Seeing your GP about erectile dysfunction

If you are experiencing erectile dysfunction for the first time, it is a good idea to see your GP. ED can be an early warning sign of underlying health conditions such as heart disease, diabetes, or high blood pressure. Your GP can arrange tests, discuss lifestyle changes, and refer you to a specialist if needed [1][2].