Taking Tadalafil First Time? Here's What to Expect

Tadalafil First Time: What to Expect and How to Take It Safely

Published: 15 October 2026

If you're taking tadalafil first time, you'll typically start with a 10 mg on-demand tablet taken at least 30 minutes before sexual activity, though your prescriber may recommend a different dose depending on your health and other medicines[4]. Tadalafil (the active ingredient in Cialis) is a PDE5 inhibitor that helps men with erectile dysfunction achieve and maintain an erection when sexually aroused, and its effects can last up to 36 hours[4]. This guide explains what to expect, how to use it safely, and how to get the best results from your first dose.

What is tadalafil and how does it work?

Tadalafil is a prescription medicine licensed in the UK to treat erectile dysfunction (ED) in adult men[4]. It belongs to a group of medicines called PDE5 inhibitors, which work by relaxing the blood vessels in the penis, allowing more blood to flow in when you are sexually aroused[1]. This increased blood flow makes it easier to get and keep an erection firm enough for sex.

It's important to understand that tadalafil does not cause an automatic erection—you still need sexual stimulation for it to work[4]. The medicine simply helps your body respond more effectively to that stimulation. Tadalafil is available as generic tablets and under the brand name Cialis, and both contain the same active ingredient and work in the same way[4].

Tadalafil is different from sildenafil (Viagra) because its effects last much longer—up to 36 hours compared to about 4–6 hours for sildenafil[3][4]. This longer window means you don't need to time sex as precisely, which many men find reduces pressure and feels more spontaneous. However, tadalafil doesn't treat the underlying causes of ED, so it's worth seeing your GP to check for conditions like diabetes or heart disease that can contribute to erection problems[1][2].

What dose should you take when using tadalafil first time?

For most men taking tadalafil first time, the recommended starting dose is 10 mg taken on-demand, at least 30 minutes before you plan to have sex[4]. Your prescriber may adjust this dose based on how well it works and whether you experience any side effects. If 10 mg is effective but you have side effects, the dose might be reduced to 5 mg; if 10 mg doesn't work well enough and you tolerate it without problems, it can be increased to 20 mg[4].

Tadalafil is also available as a daily low-dose option (2.5 mg or 5 mg taken every day), which keeps a steady level of the medicine in your system so you can be ready for sex at any time without planning ahead[4]. However, the on-demand 10 mg dose is usually the first choice for men starting treatment, as it allows you to see how your body responds before committing to daily use.

Never take more than one on-demand dose in 24 hours, and don't combine tadalafil with any other erectile dysfunction medicine or take it if you use nitrate medicines for chest pain, as this combination can cause a dangerous drop in blood pressure[4]. During your online consultation at Cured Pharmacy, a UK prescriber will review your medical history and current medicines to confirm the safest starting dose for you.

Can the dose be adjusted after the first time?

Yes, your dose can be adjusted based on your response[4]. If you find that 10 mg works well with no troublesome side effects, you may continue on that dose. If you experience side effects such as headache, indigestion, or back pain, your prescriber might lower the dose to 5 mg. Conversely, if 10 mg doesn't produce a strong enough effect and you tolerate it well, the dose can be increased to the maximum of 20 mg[4]. Always discuss any changes with your prescriber rather than adjusting the dose yourself.

How to take tadalafil first time: practical instructions

Take your tadalafil tablet at least 30 minutes before you plan to have sex, though it can work faster in some men and may take up to 2 hours to reach full effect[4]. Swallow the tablet whole with water—you can take it with or without food, as meals don't significantly affect how tadalafil is absorbed[4]. Avoid drinking large amounts of alcohol before sex, as heavy drinking can make it harder to get an erection and may increase the risk of side effects like dizziness[4].

Remember that tadalafil only works when you are sexually stimulated, so foreplay and arousal are still important[4]. The medicine doesn't increase sexual desire or cause an erection on its own; it simply makes it easier for your body to respond to natural sexual cues. Because tadalafil can remain effective for up to 36 hours, you have a long window of opportunity, which can take some of the pressure off timing[4].

If your first dose doesn't work as well as you hoped, don't be discouraged—it can take a few attempts for your body to adjust, and anxiety or nervousness can interfere with the medicine's effectiveness[2]. Give it a fair trial over several occasions, and if it still doesn't work, speak to your prescriber about adjusting the dose or trying a different ED medicine. Never take a double dose or combine tadalafil with another PDE5 inhibitor.

What to expect when taking tadalafil for the first time

When you take tadalafil first time, you may notice that getting an erection feels easier and more natural when you're sexually aroused, usually within 30 minutes to 2 hours of taking the tablet[4]. The erection should be firm enough for penetration and should last as long as you remain sexually stimulated. After ejaculation or when stimulation stops, the erection will subside naturally, just as it would without the medicine[4].

Some men experience mild side effects on their first dose, the most common being headache, indigestion, back pain, muscle aches, flushing, or a stuffy nose[4]. These effects are usually mild and temporary, often improving as your body gets used to the medicine. Drinking plenty of water and avoiding heavy meals or excessive alcohol can help minimise discomfort. If side effects are troublesome or persistent, contact your prescriber to discuss whether a lower dose might be more suitable.

It's also normal to feel a bit anxious the first time you try any ED treatment, and this anxiety can sometimes interfere with the medicine's effectiveness[2]. Try to relax, communicate openly with your partner, and remember that tadalafil has been shown to help the majority of men with ED in clinical trials[4]. If the first attempt doesn't go perfectly, give it another try on a different occasion—many men find that results improve once initial nerves settle.

How long does tadalafil last after the first dose?

Tadalafil can remain effective for up to 36 hours after a single on-demand dose, which is why it's sometimes called 'the weekend pill'[4]. This doesn't mean you'll have a continuous erection for 36 hours—it means that during this window, you can achieve an erection more easily when sexually aroused. The long duration gives you flexibility and can make sex feel more spontaneous, as you don't need to plan as precisely as with shorter-acting medicines like sildenafil[3][4].

Common side effects and how to manage them on tadalafil first time

The most frequently reported side effects when taking tadalafil include headache, indigestion (dyspepsia), back pain, muscle aches, facial flushing, and nasal congestion[4]. These effects are usually mild to moderate and often resolve on their own within a few hours. Headaches can sometimes be eased with a simple painkiller like paracetamol (avoid aspirin or ibuprofen if you have any contraindications), and indigestion may improve if you avoid large or fatty meals before taking the tablet[4].

Back pain and muscle aches, which can occur 12–24 hours after taking tadalafil, typically disappear within 48 hours[4]. Staying hydrated and gently stretching may help. Facial flushing and a blocked nose are caused by the same blood-vessel-relaxing effect that helps with erections and are generally harmless, though they can be uncomfortable. If any side effect becomes severe or doesn't go away, contact your GP or pharmacist for advice.

Rarely, tadalafil can cause more serious side effects such as sudden vision or hearing loss, chest pain during sex, or an erection lasting more than 4 hours (priapism)[4]. If you experience any of these, stop taking the medicine and seek urgent medical help. Always read the patient information leaflet that comes with your medicine and report any unexpected or concerning symptoms to a healthcare professional.

Important safety checks before taking tadalafil first time

Before you take tadalafil for the first time, a prescriber must review your medical history and current medicines to ensure it's safe for you[4]. Tadalafil must never be taken with nitrate medicines (such as GTN spray, isosorbide mononitrate, or isosorbide dinitrate) used for angina, or with nicorandil or riociguat, because the combination can cause a dangerous drop in blood pressure[4]. It's also unsafe to use tadalafil with recreational drugs known as 'poppers' (amyl or alkyl nitrites) for the same reason.

If you take alpha-blockers for an enlarged prostate or high blood pressure (such as tamsulosin or doxazosin), you may still be able to use tadalafil, but you must be stable on the alpha-blocker and start on a low dose of tadalafil under medical supervision[4]. Some medicines that affect liver enzymes—such as ritonavir, ketoconazole, itraconazole, or clarithromycin—can increase tadalafil levels in your blood, so your prescriber may need to adjust your dose or advise against using tadalafil[4].

Tadalafil is not suitable if you've had a recent heart attack or stroke, have severe heart failure, very low blood pressure, or a history of sudden vision loss (non-arteritic anterior ischaemic optic neuropathy, or NAION)[4]. Your prescriber will also check whether sexual activity itself is safe for you, particularly if you have heart disease. During your consultation at Cured Pharmacy, declare all medicines you take—including over-the-counter products, herbal remedies, and recreational drugs—so the prescriber can make a fully informed decision.

Can you take tadalafil with other medicines?

Many men take tadalafil safely alongside other medicines, but some combinations require caution or are not allowed[4]. The prescriber or pharmacist will check every medicine you're taking during your consultation. Never assume a combination is safe without professional advice, and never stop or change a prescribed medicine on your own. If you're prescribed a new medicine by your GP after starting tadalafil, tell them you're using ED treatment so they can check for interactions.

Scientific References

1. NHS. (n.d.). Erectile dysfunction (impotence). NHS website. https://www.nhs.uk/conditions/erection-problems-erectile-dysfunction/ [accessed 15 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 15 October 2026]
3. Joint Formulary Committee. (n.d.). Sildenafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/sildenafil/ [accessed 15 October 2026]
4. Joint Formulary Committee. (n.d.). Tadalafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/tadalafil/ [accessed 15 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.