Tadalafil and Exenatide: Can You Take Them Together?

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What is tadalafil and exenatide used for?

Tadalafil is a phosphodiesterase type 5 (PDE5) inhibitor licensed in the UK to treat erectile dysfunction [4]. It works by relaxing blood vessels in the penis, allowing increased blood flow when you are sexually aroused. Tadalafil is available as on-demand tablets (10 mg or 20 mg, taken at least 30 minutes before sex, with effects lasting up to 36 hours) or as a daily low-dose option (2.5 mg or 5 mg) [4]. It requires sexual stimulation to work and does not increase desire on its own.

Exenatide is a glucagon-like peptide-1 (GLP-1) receptor agonist prescribed for adults with type 2 diabetes [12]. It helps control blood sugar levels by stimulating insulin release when glucose is high, slowing stomach emptying, and reducing appetite. Exenatide is given by injection, either twice daily (Byetta) or once weekly (Bydureon). Many men with type 2 diabetes also experience erectile dysfunction, so it is not uncommon to need both medicines [1][2].

Because diabetes itself is a significant risk factor for ED—affecting blood vessels and nerves—managing your blood sugar well can sometimes improve erectile function over time [10]. Your prescriber will want to understand how well controlled your diabetes is and whether you have any diabetes-related complications before recommending tadalafil.

Is there an interaction between tadalafil and exenatide?

There is no well-documented direct pharmacological interaction between tadalafil and exenatide. They work through entirely different mechanisms in the body: tadalafil acts on blood vessels in the penis, while exenatide targets blood sugar regulation via the GLP-1 receptor system. Neither medicine is known to significantly affect the metabolism or effectiveness of the other.

However, both medicines can influence blood pressure. Tadalafil can cause a modest drop in blood pressure as part of its blood-vessel-relaxing effect [4]. Exenatide is not primarily a blood-pressure medicine, but some people experience nausea or dizziness, especially when starting treatment. If you feel dizzy or unwell, the combination might feel more noticeable, though this is not a dangerous interaction.

Your prescriber will still need to review your full medication list and medical history during the online consultation. Diabetes is often accompanied by other conditions—such as high blood pressure or heart disease—that do affect whether tadalafil is suitable for you [2]. The consultation ensures that all your medicines and health conditions are considered together, not just the two medicines in isolation.

Why your diabetes matters when taking tadalafil

Erectile dysfunction is common in men with diabetes, affecting around half of men with the condition [1][10]. Poorly controlled blood sugar can damage blood vessels and nerves over time, making erections harder to achieve. If you also have diabetic complications—such as heart disease, kidney problems, or neuropathy—your prescriber will assess whether sexual activity and ED treatment are safe for you [2]. Tadalafil is not suitable if sexual activity itself is inadvisable, for example after a recent heart attack or stroke, or if you have severe heart failure or very low blood pressure [4].

When to get urgent help

• Erection lasting longer than four hours (priapism)—go to A&E immediately
• Sudden loss of vision in one or both eyes—stop tadalafil and seek urgent medical help
• Sudden decrease or loss of hearing, possibly with ringing in the ears or dizziness—stop tadalafil and contact a doctor
• Chest pain during or after sex—do not use nitrate medicines; tell the doctor you have taken tadalafil
• Severe dizziness, fainting, or feeling very unwell—sit or lie down and seek medical advice promptly

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

What does the prescriber check before approving tadalafil and exenatide together?

During your online consultation at Cured Pharmacy, the prescriber will ask about your current medicines, including exenatide, and any other treatments for diabetes or related conditions. They will want to know how well your diabetes is controlled, whether you have any complications (such as heart disease, high blood pressure, or kidney problems), and whether you take any other medicines that might interact with tadalafil [2][4].

Certain medicines must never be taken with tadalafil because they can cause a dangerous drop in blood pressure. These include nitrates (such as GTN spray or isosorbide mononitrate), nicorandil, riociguat, and recreational drugs called 'poppers' (alkyl nitrites) [3][4]. If you take any of these, do not take tadalafil. Alpha-blockers (such as tamsulosin or doxazosin, often used for prostate symptoms) can also lower blood pressure when combined with tadalafil, so you must be stable on the alpha-blocker and start on the lowest dose of tadalafil [4].

If you take other blood-pressure medicines alongside your diabetes treatment, the prescriber will check that your blood pressure is stable and that adding tadalafil is unlikely to cause dizziness or fainting. You should never stop or change a prescribed medicine without speaking to your doctor or pharmacist first. The consultation is designed to ensure that tadalafil is safe and appropriate for your individual circumstances.

Practical advice for taking tadalafil with exenatide

If your prescriber approves tadalafil, you can take it on the same day as your exenatide injection without any special timing requirements. Exenatide is usually injected before meals (twice daily) or once a week, depending on the formulation, while tadalafil on-demand tablets are taken at least 30 minutes before sexual activity [4][12]. There is no need to separate the doses by a set number of hours.

Take tadalafil exactly as prescribed—usually 10 mg to start, which can be adjusted to 20 mg or reduced to 5 mg depending on how well it works and any side effects you experience [4]. Do not take more than one dose in 24 hours. Tadalafil requires sexual stimulation to work; it will not cause an erection on its own. The effect can last up to 36 hours, so you do not need to time it precisely.

Avoid drinking large amounts of alcohol when taking tadalafil, as heavy drinking can make erectile dysfunction worse and add to the blood-pressure-lowering effect, increasing the risk of dizziness [4]. Grapefruit juice can raise tadalafil levels in your blood, so it is best avoided. If you experience side effects such as headache, indigestion, back pain, or flushing, these are usually mild and temporary [4]. However, if you feel dizzy or unwell, sit or lie down and avoid driving or operating machinery until you feel better.

Monitoring your diabetes while using ED treatment

Continue to monitor your blood sugar levels as advised by your diabetes team. Tadalafil does not directly affect blood glucose, but stress, changes in activity, or feeling unwell can all influence your diabetes control. If you notice any unusual symptoms or your blood sugar becomes harder to manage, speak to your GP or diabetes nurse. Regular check-ups are important to ensure both your diabetes and any related conditions remain well controlled [2].

At a glance

What are the warning signs to watch for with tadalafil and exenatide?

Most men take tadalafil without serious problems, but you should be aware of warning signs that need urgent medical attention. If you develop an erection that lasts longer than four hours (priapism), go to A&E immediately—this is a medical emergency that can cause permanent damage if not treated quickly [4]. Priapism is rare but requires urgent help.

Sudden loss of vision in one or both eyes, or sudden decrease or loss of hearing (sometimes with ringing in the ears or dizziness), are also rare but serious side effects. Stop taking tadalafil and seek medical help straight away if this happens [4]. If you experience chest pain during or after sex, do not use nitrate medicines to treat it—tell the doctor or paramedic that you have taken tadalafil, as nitrates and tadalafil together can cause a dangerous drop in blood pressure [4].

If you feel very dizzy, faint, or unwell after taking tadalafil, especially if you also take blood-pressure medicines, sit or lie down and seek advice from your pharmacist or GP. Exenatide can cause nausea, vomiting, or diarrhoea, particularly when you first start it [12]. If you become dehydrated from these side effects, you may feel more dizzy when taking tadalafil. Make sure you drink plenty of fluids and contact your diabetes team if side effects from exenatide are troublesome.

How to access tadalafil safely at Cured Pharmacy

Tadalafil is a prescription-only medicine in the UK, so you will need to complete an online consultation before it can be supplied [4]. At Cured Pharmacy, a UK-registered prescriber reviews every consultation to ensure the treatment is safe and suitable for you. You will be asked about your medical history, current medicines (including exenatide and any other diabetes treatments), and any other health conditions.

If approved, your tadalafil will be dispensed by our GPhC-registered pharmacy (GPhC 9012511) and delivered discreetly to your door. We offer a range of tadalafil options, including generic tadalafil from £7.95 (first order with code Ednew: £6.36) and branded Cialis from £12.00 (first order with code Ednew: £9.60). Tadalafil 20 mg (Teva) is available at £9.99 (first order with code Ednew: £7.99), and Avarante (tadalafil) 10 mg at £11.49 (first order with code Ednew: £9.19).

If you have not seen a doctor about your erectile dysfunction before, we strongly encourage you to speak to your GP as well. ED can be an early warning sign of heart disease or poorly controlled diabetes, and your GP can arrange tests and review your overall health [1][2]. Online treatment is convenient and confidential, but it works best alongside regular check-ups with your usual healthcare team. Our pharmacists are always available if you have questions about your treatment or need advice about taking tadalafil with your other medicines.

Other ED treatments available

If tadalafil is not suitable or you would like to try a different option, Cured Pharmacy also offers sildenafil (generic Viagra) from £0.45, vardenafil (generic Levitra) at £16.95, and Spedra (avanafil) at £20.95 (all with first-order discounts using code Ednew) [3][5][6]. Each medicine works in a similar way but differs in how quickly it starts working and how long it lasts. Your prescriber can help you choose the best option based on your preferences and medical history.

In summary

• No major direct interaction is reported between tadalafil and exenatide—they can usually be taken together safely.
• Your prescriber will check your diabetes control, heart health, and all other medicines before approving tadalafil.
• Tadalafil does not affect blood sugar levels; continue monitoring your diabetes as advised by your healthcare team.
• Seek urgent help if you have an erection lasting over four hours, sudden vision or hearing loss, or chest pain during sex.

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