Tadalafil and Nalmefene: Can You Take Them Together?
Learn how these medicines interact and what your prescriber checks during your UK pharmacist-led consultation.
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Tadalafil and Nalmefene: Understanding the Interaction
Published: 23 October 2026
If you've been prescribed tadalafil for erectile dysfunction and nalmefene to help reduce alcohol consumption, you may wonder whether tadalafil and nalmefene can be taken together safely. The good news is that no major direct drug interaction between these two medicines is commonly reported in clinical databases. However, both medicines can affect your body in ways that require careful consideration, and your prescriber will review your full medication list and health history during your consultation to ensure the combination is appropriate for you.
Reduce alcohol to improve ED
If you're taking nalmefene to cut down your drinking, you may notice your erectile function improves as your alcohol intake reduces. Heavy drinking is a common cause of ED, and reducing it supports better blood flow and overall sexual health.
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 phosphodiesterase type 5 (PDE5) inhibitors, which work by relaxing the blood vessels in the penis, allowing more blood to flow in when you are sexually aroused. This increased blood flow can help you achieve and maintain an erection suitable for sexual activity.
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 low-dose tablets (2.5mg or 5mg) taken once a day at the same time [4]. Both require sexual stimulation to work—tadalafil will not cause an erection on its own.
Common brand names include Cialis (the original branded version) and various generics. At Cured Pharmacy, tadalafil is available after an online consultation reviewed by a UK-registered prescriber, who will check your medical history, current medicines, and overall suitability for treatment.
What is nalmefene and why is it prescribed?
Nalmefene is a prescription medicine used to help reduce alcohol consumption in adults with alcohol dependence who have a high drinking risk level and do not have physical withdrawal symptoms [12]. It works by blocking certain receptors in the brain (opioid receptors) that are involved in the rewarding effects of alcohol, which may help reduce the urge to drink heavily.
Nalmefene is taken on an 'as-needed' basis: you take one tablet on any day you think there is a risk you might drink alcohol, ideally 1–2 hours before the anticipated time of drinking. It is not a cure for alcohol dependence but is used alongside psychosocial support to help you cut down your drinking gradually.
Common side effects of nalmefene include nausea, dizziness, headache, insomnia, and reduced appetite. Because it can cause dizziness and affect your ability to concentrate, you should be cautious when driving or operating machinery, especially when you first start taking it.
When to get urgent help
- Erection lasting more than 4 hours (priapism) – go to A&E immediately
- Sudden loss of vision or hearing – stop tadalafil and seek urgent medical help
- Chest pain during or after sexual activity – call 999; do not take more tadalafil
- Severe dizziness, fainting, or feeling very unwell – contact your GP or call 111 for advice
Call 999 or go to A&E in an emergency, or contact NHS 111 for urgent advice.
How do tadalafil and nalmefene interact?
There is no well-documented direct pharmacological interaction between tadalafil and nalmefene. They work on different systems in the body: tadalafil acts on blood vessels via the PDE5 enzyme, while nalmefene acts on opioid receptors in the brain. Neither medicine is known to significantly affect the metabolism or blood levels of the other, so taking them together does not usually pose a direct drug-interaction risk.
However, both medicines can cause dizziness as a side effect. Tadalafil can lower blood pressure slightly (which may cause dizziness or light-headedness, especially when standing up), and nalmefene commonly causes dizziness, particularly when you first start taking it. If you experience both side effects together, you may feel more unsteady or light-headed than you would with either medicine alone.
Additionally, if you are taking nalmefene because you have been drinking heavily, it's important to know that heavy alcohol consumption itself can worsen erectile dysfunction and add to the blood-pressure-lowering effect of tadalafil [1]. Reducing your alcohol intake—one of the goals of nalmefene treatment—may actually improve your ED symptoms over time.
The role of alcohol in erectile dysfunction
Alcohol is a common contributor to erectile dysfunction. While a small amount may reduce anxiety, heavy or regular drinking can interfere with the signals between your brain and penis, making it harder to achieve or maintain an erection [1]. Chronic heavy drinking can also damage blood vessels and nerves, and reduce testosterone levels, all of which can worsen ED. If you are using nalmefene to cut down your alcohol consumption, you may find that your erectile function improves as your drinking reduces, making tadalafil more effective.
What your prescriber will check before prescribing tadalafil and nalmefene together
When you request tadalafil through Cured Pharmacy's online consultation, a UK-registered prescriber will review your full medical history and all current medicines, including nalmefene. They will check that you do not have any conditions that make tadalafil unsuitable, such as recent heart attack or stroke, severe heart failure, very low blood pressure, or use of nitrate medicines (such as GTN spray or isosorbide mononitrate), nicorandil, riociguat, or recreational drugs called 'poppers' [3][4].
The prescriber will also ask about your alcohol consumption and any other medicines you take. If you are taking nalmefene, they will want to understand your drinking pattern and whether you have any liver problems, as both heavy alcohol use and liver disease can affect how medicines are processed in your body. They may recommend starting tadalafil at a lower dose if there are concerns about dizziness or blood pressure.
It is essential to be honest and complete in your consultation answers. Do not stop or change your nalmefene (or any other prescribed medicine) without speaking to the doctor who prescribed it. If your prescriber has any concerns about the combination, they will discuss alternatives or additional monitoring with you.
At a glance
Practical advice for taking tadalafil and nalmefene safely
If your prescriber approves the combination of tadalafil and nalmefene, follow these practical tips to minimise side effects and get the best results. Take each medicine exactly as prescribed: nalmefene on days you anticipate drinking (1–2 hours before), and tadalafil either daily (at the same time each day) or on-demand (at least 30 minutes before sexual activity, depending on your dose) [4][12].
Be especially cautious about dizziness when you first start either medicine or if you increase your dose. Avoid standing up quickly from sitting or lying down, as this can trigger a sudden drop in blood pressure. If you feel dizzy, sit or lie down until it passes, and avoid driving or using machinery until you know how the combination affects you.
Limit your alcohol intake. Even though nalmefene is designed to help you reduce drinking, if you do drink alcohol, keep it moderate. Heavy drinking will make erectile dysfunction worse, increase the risk of dizziness and low blood pressure with tadalafil, and may reduce the effectiveness of both medicines. Avoid grapefruit juice while taking tadalafil, as it can raise tadalafil levels in your blood and increase the risk of side effects.
When to seek medical advice
Contact your GP or prescriber if you experience persistent or severe dizziness, fainting, or any new symptoms after starting the combination. Seek urgent medical help (call 999 or go to A&E) if you have an erection lasting more than four hours (priapism), sudden loss of vision or hearing, or chest pain during sexual activity. These are rare but serious side effects of tadalafil that require immediate treatment [4].
Other medicines and lifestyle factors to consider with tadalafil and nalmefene
Beyond nalmefene, several other medicines and lifestyle factors can interact with tadalafil. Never take tadalafil with nitrates (GTN spray, isosorbide mononitrate or dinitrate), nicorandil, riociguat, or recreational 'poppers' (amyl or alkyl nitrites), as the combination can cause a dangerous drop in blood pressure [4]. Do not take tadalafil with another PDE5 inhibitor (such as sildenafil or vardenafil) at the same time.
If you take alpha-blockers for prostate symptoms or high blood pressure (such as tamsulosin, doxazosin, or alfuzosin), tell your prescriber, as these can also lower blood pressure and may require a lower starting dose of tadalafil [4]. Some medicines that affect liver enzymes—such as ritonavir, cobicistat, ketoconazole, itraconazole, or clarithromycin—can raise tadalafil levels, requiring dose adjustments, while others like rifampicin or St John's wort can make tadalafil less effective.
Lifestyle changes can also improve erectile dysfunction. Regular exercise, a healthy diet, stopping smoking, reducing alcohol, and managing stress or anxiety all support better erections and overall cardiovascular health [1][2]. If your ED is new or worsening, see your GP for a full assessment, as it can be an early warning sign of heart disease or diabetes.
Tadalafil options at Cured Pharmacy
Cured Pharmacy offers a range of tadalafil products after an online consultation reviewed by a UK prescriber. Options include generic Tadalafil from £7.95 (first order £6.36 with code Ednew), Tadalafil 20mg (Teva) at £9.99 (first order £7.99), Avarante (tadalafil) 10mg at £11.49 (first order £9.19), and branded Cialis at £12.00 (first order £9.60). All prices include the consultation and delivery. Your prescriber will recommend the most suitable dose and formulation based on your individual needs and medical history.
In summary
- No major direct interaction is reported between tadalafil and nalmefene; they can usually be taken together safely.
- Both medicines can cause dizziness, so be cautious when standing up and avoid driving until you know how they affect you.
- Heavy alcohol worsens erectile dysfunction and increases side effects; reducing drinking may improve your ED.
- Always declare all medicines, including nalmefene, in your online consultation so your prescriber can check for safety.
- Never take tadalafil with nitrates, nicorandil, riociguat, poppers, or another PDE5 inhibitor.
Scientific References
- NHS. (n.d.). Erectile dysfunction (impotence). NHS website. https://www.nhs.uk/conditions/erection-problems-erectile-dysfunction/ [accessed 23 October 2026]
- National Institute for Health and Care Excellence. (n.d.). Erectile dysfunction. Clinical Knowledge Summaries. https://cks.nice.org.uk/topics/erectile-dysfunction/ [accessed 23 October 2026]
- Joint Formulary Committee. (n.d.). Sildenafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/sildenafil/ [accessed 23 October 2026]
- Joint Formulary Committee. (n.d.). Tadalafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/tadalafil/ [accessed 23 October 2026]
- Electronic Medicines Compendium. (n.d.). Summaries of Product Characteristics and Patient Information Leaflets. https://www.medicines.org.uk/emc/ [accessed 23 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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