Tadalafil vs Cialis Together: Are They the Same?

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Tadalafil vs Cialis Together: Understanding the Difference

Published: 17 October 2026

Many people search for information about tadalafil vs Cialis together, wondering if these are different medicines or whether they can be combined. The short answer is that tadalafil and Cialis are the same active ingredient—Cialis is simply the original branded version, while tadalafil is the generic equivalent. You should never take both together, as this would mean doubling your dose and risking serious side effects. This page explains how tadalafil and Cialis compare, who each option may suit, and how to access treatment safely through a UK pharmacist-led consultation.

What Is the Difference Between Tadalafil and Cialis?

Tadalafil is the active pharmaceutical ingredient in both generic tadalafil tablets and the branded medicine Cialis [4]. When Cialis was first developed by Eli Lilly, it held patent protection, meaning only the brand-name version was available. Once the patent expired, other manufacturers were licensed to produce generic tadalafil containing exactly the same active ingredient at the same doses.

Both generic tadalafil and branded Cialis work in the same way: they belong to a class of medicines called PDE5 inhibitors, which help increase blood flow to the penis during sexual stimulation [1][4]. The main differences lie in the manufacturer, packaging, and price. Generic tadalafil is typically much more affordable because manufacturers do not carry the research and marketing costs associated with the original brand.

In the UK, both generic tadalafil and branded Cialis are prescription medicines. They are available in on-demand doses (10 mg and 20 mg, taken at least 30 minutes before sexual activity) and daily doses (2.5 mg and 5 mg for regular use) [4]. The effect of a single on-demand dose can last up to 36 hours, which is why tadalafil is sometimes called the 'weekend pill'.

Can You Take Tadalafil and Cialis Together?

No, you should never take tadalafil and Cialis together. Because they contain the same active ingredient, taking both would effectively double your dose, significantly increasing the risk of side effects such as headaches, dizziness, flushing, indigestion, and a dangerous drop in blood pressure [4]. Combining PDE5 inhibitors is also explicitly contraindicated in UK prescribing guidance.

It is equally important never to take tadalafil or Cialis alongside any other erectile dysfunction medicine, such as sildenafil (Viagra), vardenafil (Levitra), or avanafil (Spedra), on the same day [1][2]. All of these medicines work in a similar way, and combining them does not improve effectiveness—it only raises the risk of harm.

If you are considering switching from Cialis to generic tadalafil, or vice versa, you can do so safely because they are bioequivalent. However, you should only take one dose of one product in any 24-hour period. Always follow the dosing instructions provided by your prescriber and pharmacist, and never exceed the maximum recommended dose.

What If I've Accidentally Taken Both?

If you have accidentally taken both tadalafil and Cialis on the same day, contact NHS 111 or your GP immediately for advice. Do not take any more doses until you have spoken to a healthcare professional. Symptoms of overdose may include severe dizziness, fainting, prolonged erection (priapism), or visual disturbances. If you experience chest pain, a sudden drop in blood pressure, or an erection lasting more than four hours, seek emergency medical help by calling 999 or attending A&E [4].

Tadalafil vs Cialis Together: How Do They Compare in Practice?

When comparing tadalafil vs Cialis together in terms of clinical performance, the two are equivalent. Both contain the same active ingredient at the same strengths, are absorbed in the same way, and produce the same therapeutic effect [4]. Clinical trials and real-world evidence show that generic tadalafil is just as effective and safe as branded Cialis.

The onset of action for both is similar: you should take an on-demand dose at least 30 minutes before sexual activity, though some men find it works faster. The effect can last up to 36 hours, giving you a wide window of opportunity without needing to time intercourse precisely [4]. Both medicines require sexual stimulation to work—they do not cause an automatic erection.

Food does not significantly affect the absorption of either tadalafil or Cialis, so you can take them with or without meals [4]. However, heavy alcohol can worsen erectile dysfunction and add to the blood-pressure-lowering effect of the medicine, so it is best to drink only in moderation. Grapefruit juice should be avoided, as it can raise tadalafil levels in the blood and increase the risk of side effects.

The main practical difference is cost. Generic tadalafil is considerably less expensive than branded Cialis, making it a more accessible option for many men. At Cured Pharmacy, generic tadalafil is priced at £7.95 (or £6.36 for first orders with code Ednew), while branded Cialis costs £12.00 (£9.60 with code Ednew). Both require a prescription following an online consultation with a UK-registered prescriber.

Who Might Prefer Generic Tadalafil or Branded Cialis?

Most men will find that generic tadalafil meets their needs effectively and affordably. Because it contains the same active ingredient at the same dose, it offers the same clinical benefit as Cialis at a lower price [4]. For men who are cost-conscious or who use the treatment regularly, generic tadalafil is often the preferred choice.

Some men prefer branded Cialis for reasons of familiarity, reassurance, or personal preference. If you have been using Cialis for years and are happy with it, there is no medical need to switch to the generic version. However, if you are open to trying the generic, you can expect the same results at a lower cost.

Both options are suitable for the same groups of men: those aged 18 and over with erectile dysfunction, provided there are no contraindications [2][4]. Neither is suitable if you take nitrates (such as GTN spray or isosorbide mononitrate), nicorandil, riociguat, or recreational drugs known as 'poppers', because the combination can cause a dangerous drop in blood pressure. Men taking alpha-blockers (such as tamsulosin or doxazosin) or potent CYP3A4 inhibitors (such as ritonavil, ketoconazole, or clarithromycin) need careful dose adjustment and must declare these medicines during the consultation [4].

Switching Between Generic and Branded Versions

Switching from Cialis to generic tadalafil, or from generic to branded, is straightforward because they are bioequivalent. You do not need to adjust your dose or change how you take the medicine. Simply continue with the same strength and timing as before. If you have any concerns or notice any difference in how the medicine works for you, speak to your pharmacist or prescriber for reassurance and advice.

Side Effects: Are They the Same for Tadalafil and Cialis?

Yes, the side effects of generic tadalafil and branded Cialis are identical, because they contain the same active ingredient [4]. Common side effects include headache, indigestion, back pain, muscle aches, flushing, and nasal congestion. These are usually mild and temporary, often improving as your body adjusts to the medicine.

Less common but more serious side effects include a sudden drop in blood pressure (especially if taken with certain other medicines), prolonged or painful erection (priapism), sudden loss of vision in one or both eyes, and sudden decrease or loss of hearing [4]. If you experience any of these, stop taking the medicine and seek urgent medical attention.

The risk of side effects is the same whether you take generic tadalafil or branded Cialis, provided you take the same dose. However, taking both together would double your dose and significantly increase the likelihood and severity of side effects. This is why it is essential never to combine the two or to take tadalafil or Cialis with any other PDE5 inhibitor.

If you experience side effects that are troublesome or persistent, do not simply stop the medicine without advice. Contact your prescriber or pharmacist, who may be able to adjust your dose, suggest taking the medicine at a different time, or recommend an alternative treatment such as sildenafil or vardenafil [2].

How to Access Tadalafil or Cialis Safely in the UK

Both generic tadalafil and branded Cialis are prescription-only medicines in the UK, which means you need a consultation with a qualified prescriber before you can buy them [2][4]. At Cured Pharmacy, a GPhC-registered online pharmacy (GPhC 9012511), you can complete a short online health questionnaire that is reviewed by a UK-registered prescriber. If the treatment is suitable and safe for you, a prescription is issued and your medicine is dispensed and posted discreetly to your home.

During the consultation, you will be asked about your medical history, current medicines, and any other health conditions. It is essential to answer honestly and completely, because certain medicines and conditions mean tadalafil or Cialis may not be safe for you. For example, if you take nitrates for angina, or if you have severe heart failure or very low blood pressure, PDE5 inhibitors are contraindicated [4].

If you are experiencing erectile dysfunction for the first time, it is a good idea to see your GP as well. Erectile dysfunction can be an early warning sign of cardiovascular disease or diabetes, and your GP can arrange tests and address any underlying health issues [1][2]. Treating ED with medicine is effective, but it works best alongside a healthy lifestyle: maintaining a healthy weight, exercising regularly, limiting alcohol, stopping smoking, and managing stress all improve erectile function.

At Cured Pharmacy, we offer both generic tadalafil (from £7.95, or £6.36 with code Ednew) and branded Cialis (£12.00, or £9.60 with code Ednew), as well as other ED treatments including sildenafil, vardenafil, and avanafil. Your prescriber will help you choose the option that best suits your needs, lifestyle, and budget.

What Happens During the Online Consultation?

The online consultation is designed to be quick, confidential, and thorough. You will answer questions about your general health, any medicines you currently take (including over-the-counter and herbal products), your blood pressure, and your heart health. The prescriber will check for any contraindications or interactions, and if everything is safe, they will approve your prescription. If tadalafil or Cialis is not suitable, the prescriber may suggest an alternative treatment or advise you to see your GP for further assessment.

Scientific References

1. NHS. (n.d.). Erectile dysfunction (impotence). NHS website. https://www.nhs.uk/conditions/erection-problems-erectile-dysfunction/ [accessed 17 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 17 October 2026]
3. Joint Formulary Committee. (n.d.). Tadalafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/tadalafil/ [accessed 17 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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