Tadalafil and Agomelatine: Can You Take Them Together?

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Key takeaways

• No major interaction is commonly reported between tadalafil and agomelatine
• Your prescriber reviews all your medicines during the consultation to ensure safety
• Depression and ED often occur together; treating both is important
• Never stop agomelatine without medical advice as it could affect your mental health
• Seek urgent help for erections over four hours or sudden vision or hearing loss

What Is Tadalafil and How Does It Work?

Tadalafil is a prescription 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 increased blood flow when you are sexually aroused. Tadalafil is the generic version of Cialis and is available in two forms: on-demand tablets (10mg or 20mg taken at least 30 minutes before sex, with effects lasting up to 36 hours) and daily tablets (2.5mg or 5mg taken once a day) [4].

Unlike some other ED treatments, tadalafil does not cause an erection on its own—sexual stimulation is still needed for it to work [4]. The long duration of action has earned it the nickname 'the weekend pill', as a single dose can provide the opportunity for sexual activity over a longer period compared to shorter-acting alternatives. Tadalafil is only available on prescription in the UK after a clinical assessment by a registered prescriber, who will check that it is safe and suitable for you.

What Is Agomelatine and Why Is It Prescribed?

Agomelatine is a prescription antidepressant used to treat major depressive episodes in adults. It works differently from many other antidepressants: it acts on melatonin receptors (MT1 and MT2) to help regulate your body clock and sleep-wake cycle, and it also blocks certain serotonin receptors (5-HT2C) which may improve mood and reduce anxiety. Agomelatine is usually taken once daily in the evening.

Depression itself can contribute to erectile dysfunction, so treating the underlying mental health condition is an important part of managing ED [1][2]. However, some antidepressants—particularly SSRIs and SNRIs—can themselves cause or worsen sexual problems as a side effect. Agomelatine is generally considered to have a lower risk of sexual side effects compared to many other antidepressants, which is one reason it may be chosen for people experiencing both depression and ED.

How Depression and ED Are Linked

Erectile dysfunction and depression often occur together [10]. Depression can reduce libido, affect self-esteem, and interfere with the physical processes needed for an erection. At the same time, experiencing ED can lead to anxiety, low mood, and relationship difficulties, creating a cycle that affects both mental and sexual health. Treating depression effectively—whether with medication, talking therapy, or both—can sometimes improve erectile function as well [2].

At a glance

Can You Take Tadalafil and Agomelatine Together?

No major interaction is commonly reported between tadalafil and agomelatine, and many men take both medicines together without problems. Agomelatine is not known to significantly affect the way tadalafil works, and tadalafil does not interfere with the antidepressant action of agomelatine. However, every person's situation is different, and your prescriber will review your full medication list and medical history during your consultation to ensure the combination is safe for you.

It is important to declare all medicines you are taking—including prescription drugs, over-the-counter products, and herbal supplements—when you request treatment for ED. Your prescriber will check for any potential interactions and ensure that tadalafil is suitable given your overall health. Never stop or change a prescribed medicine like agomelatine without speaking to the doctor who prescribed it, as this could affect your mental health.

What Your Prescriber Checks Before Approving Tadalafil

Before prescribing tadalafil, your clinician will ask about your current medicines, medical conditions, and cardiovascular health. Tadalafil is not suitable for everyone: it must never be taken with nitrates (such as GTN spray or isosorbide mononitrate), nicorandil, riociguat, or recreational drugs called 'poppers', as these combinations can cause a dangerous drop in blood pressure [4]. It is also not recommended if you have had a recent heart attack or stroke, have unstable angina, severe heart failure, very low blood pressure, or certain eye conditions such as previous sudden vision loss (NAION) [4].

If you take medicines for high blood pressure or an enlarged prostate (alpha-blockers like tamsulosin or doxazosin), your prescriber will ensure you are stable on that treatment and may start you on a lower dose of tadalafil to reduce the risk of dizziness or low blood pressure [4]. Certain medicines that affect liver enzymes (such as ritonavir, ketoconazole, or clarithromycin) can increase tadalafil levels in your blood, so dose adjustments may be needed [4]. Your prescriber will also consider whether sexual activity is safe for your heart, particularly if you have cardiovascular disease [2].

The Online Consultation Process

At Cured Pharmacy, all prescription ED treatments are supplied only after an online consultation reviewed by a UK-registered prescriber. You will be asked to provide details about your health, current medications (including agomelatine), and any other relevant medical history. The prescriber will assess whether tadalafil is safe and appropriate for you, and may suggest an alternative treatment or recommend seeing your GP if further investigation is needed. This process ensures that your treatment is both effective and safe.

Tadalafil and Agomelatine: Practical Advice for Safe Use

If your prescriber approves tadalafil while you are taking agomelatine, follow the dosing instructions carefully. For on-demand tadalafil, take one tablet at least 30 minutes before you plan to have sex; the effect can last up to 36 hours, but you should not take more than one dose in 24 hours [4]. If you are prescribed daily tadalafil, take it at the same time each day, regardless of when you plan to have sex. Sexual stimulation is still needed for the medicine to work [4].

Avoid drinking large amounts of alcohol, as this can make erectile dysfunction worse and increase the risk of side effects such as dizziness, headache, or low blood pressure [4]. Grapefruit juice can raise tadalafil levels in your blood and should be avoided. Common side effects of tadalafil include headache, indigestion, back pain, muscle aches, flushing, and a blocked or runny nose; these are usually mild and temporary [4]. If you experience chest pain during sex, stop and seek urgent medical help—do not take nitrates for chest pain if you have used tadalafil in the past 48 hours [4].

When to Seek Medical Advice About Tadalafil and Agomelatine

Seek urgent medical help (call 999 or go to A&E) if you experience an erection lasting more than four hours (priapism), sudden loss of vision or hearing, or chest pain during sexual activity [4]. These are rare but serious side effects that need immediate attention. If you develop new symptoms or side effects after starting tadalafil, or if your erectile dysfunction suddenly worsens, contact your GP or the prescribing clinician for advice.

If you are starting or stopping agomelatine, or if the dose is changed, let your ED prescriber know, as this may affect your overall treatment plan. Similarly, if you develop new health problems (such as heart disease, high blood pressure, or diabetes), inform both your GP and your ED treatment provider. Erectile dysfunction can be an early warning sign of cardiovascular disease or diabetes, so it is important to see your GP for a full health check if you have not already done so [1][2]. Never stop taking agomelatine or any other prescribed medicine without medical advice, as this could affect your mental health.

Supporting Your Mental and Sexual Health

Managing both depression and erectile dysfunction requires a holistic approach. Continue taking agomelatine as prescribed, attend follow-up appointments with your GP or psychiatrist, and consider talking therapy if recommended. Lifestyle changes—such as regular exercise, a balanced diet, reducing alcohol, stopping smoking, and managing stress—can benefit both your mental health and erectile function [1][2]. Open communication with your partner about ED and mental health can also reduce anxiety and strengthen your relationship.

When to get urgent help

• Erection lasting more than four hours (priapism)
• Sudden loss of vision or hearing
• Chest pain during sexual activity
• Severe dizziness or fainting after taking tadalafil
• Allergic reaction such as swelling of the face, lips, or throat

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