Tadalafil and Dolutegravir: Can They Be Taken Together?

Takes less than 2 minutes to complete 100% online

What is Tadalafil?

Tadalafil is a prescription medicine used to treat erectile dysfunction (ED) in men. 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 [3][4]. Tadalafil does not cause an erection on its own—sexual stimulation is still needed.

Tadalafil is the generic name for Cialis and is available in two forms: on-demand tablets (10mg or 20mg) taken at least 30 minutes before sexual activity, with effects lasting up to 36 hours, and daily tablets (2.5mg or 5mg) taken once a day at the same time [4]. The on-demand option is popular because of its long duration, earning it the nickname 'the weekend pill'.

Common side effects include headache, indigestion, back pain, muscle aches, flushing, and nasal congestion [4]. Most side effects are mild and temporary. Tadalafil is only supplied after an online consultation reviewed by a UK prescriber, who will check your medical history and current medicines to ensure it is safe for you.

What is Dolutegravir?

Dolutegravir is an antiretroviral medicine used to treat HIV infection. It belongs to a class of medicines called integrase strand transfer inhibitors (INSTIs), which work by blocking an enzyme that HIV needs to multiply in the body. Dolutegravir is often prescribed as part of combination antiretroviral therapy (ART) to control HIV and maintain a healthy immune system.

Brand names for dolutegravir include Tivicay (dolutegravir alone) and combination tablets such as Triumeq (dolutegravir with abacavir and lamivudine) and Juluca (dolutegravir with rilpivirine). It is usually taken once or twice daily, with or without food, depending on the specific regimen prescribed by your HIV specialist.

Dolutegravir is generally well tolerated, with common side effects including headache, difficulty sleeping, diarrhoea, and nausea. It is important to take dolutegravir exactly as prescribed and not to miss doses, as this helps prevent the virus from developing resistance to the medicine. If you are taking dolutegravir and considering treatment for erectile dysfunction, your prescriber will need to know about it during your consultation.

When to get urgent help

• Erection lasting longer than four hours—go to A&E or call 999 immediately
• Sudden loss of vision in one or both eyes—stop tadalafil and seek urgent medical advice
• Chest pain during or after sex—stop activity and seek medical help; do not take nitrates
• Severe dizziness, fainting, or signs of allergic reaction—call 999 or go to A&E
• Sudden hearing loss or ringing in the ears—stop tadalafil and see a doctor as soon as possible

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

Do Tadalafil and Dolutegravir Interact?

No major interaction between tadalafil and dolutegravir is commonly reported in clinical practice. Dolutegravir is not a potent inhibitor of the liver enzyme (CYP3A4) that breaks down tadalafil, so it does not significantly raise tadalafil levels in the blood. This means that the two medicines can usually be taken together without needing to adjust the dose of tadalafil.

However, it is important to remember that dolutegravir is often prescribed as part of a combination tablet that includes other antiretroviral medicines. Some HIV medicines—particularly those boosted with ritonavir or cobicistat—are potent CYP3A4 inhibitors and can raise tadalafil levels, requiring a lower dose [4]. Your prescriber will check the full list of antiretrovirals you are taking, not just dolutegravir, to ensure tadalafil is safe and effective for you.

During your consultation, you will be asked to list all your current medicines, including any over-the-counter products and supplements. This allows the prescriber to identify any interactions and recommend the safest treatment plan. Never stop or change your HIV medicines without advice from your HIV specialist, as this can affect how well your treatment controls the virus.

How the Interaction is Managed

If you are taking dolutegravir alone or in a combination that does not include ritonavir or cobicistat, the standard doses of tadalafil (10mg or 20mg on-demand, or 2.5mg to 5mg daily) are usually appropriate [4]. Your prescriber will confirm this during your consultation by reviewing your full medication list and medical history.

If your HIV regimen includes a potent CYP3A4 inhibitor such as ritonavir or cobicistat, your prescriber may recommend a lower starting dose of tadalafil or a reduced maximum dose to avoid side effects. For example, if you are taking tadalafil on-demand, the maximum recommended dose may be 10mg rather than 20mg [4]. Your prescriber will explain any dose adjustments clearly and ensure you understand how to take your medicine safely.

What Your Prescriber Checks Before Prescribing Tadalafil

Before prescribing tadalafil, your prescriber will ask about your full medical history, including any heart problems, blood pressure issues, liver or kidney disease, and any conditions affecting your eyes or blood cells [4]. They will also ask about all the medicines you are currently taking, including prescription medicines, over-the-counter products, and herbal supplements.

For men taking HIV medicines, the prescriber will pay particular attention to whether your antiretroviral regimen includes any potent CYP3A4 inhibitors (such as ritonavir or cobicistat) or other medicines that can interact with tadalafil. They will also check that you are not taking any medicines that are contraindicated with tadalafil, such as nitrates (GTN spray, isosorbide mononitrate or dinitrate), nicorandil, riociguat, or amyl/alkyl nitrites (poppers) [3][4]. Do not take tadalafil together with these medicines, as the combination can cause a dangerous fall in blood pressure.

Your prescriber will also ask about your blood pressure and whether you take any alpha-blockers (such as doxazosin or tamsulosin) for prostate symptoms. If you are on an alpha-blocker, you should be stable on that medicine before starting tadalafil, and you will usually be started on the lowest dose to reduce the risk of dizziness or low blood pressure [4]. The prescriber will explain any precautions you need to take and answer any questions you have about your treatment.

Declaring All Your Medicines

It is essential to declare every medicine you are taking during your consultation, even if you think it is not relevant. This includes medicines prescribed by your GP or specialist, pharmacy medicines you have bought over the counter, herbal remedies such as St John's wort, and recreational substances. Some interactions are not immediately obvious, and your prescriber relies on accurate information to keep you safe.

If you are taking dolutegravir as part of a combination tablet, make sure to tell your prescriber the brand name (such as Triumeq or Juluca) so they can check all the active ingredients. If you are unsure about any of your medicines, bring a list or your repeat prescription to your consultation. Your prescriber is there to help, and there is no judgement—your safety is the priority.

At a glance

Practical Advice for Taking Tadalafil and Dolutegravir Together

If your prescriber confirms that tadalafil is suitable for you, take it exactly as directed. For on-demand tadalafil (10mg or 20mg), take one tablet at least 30 minutes before sexual activity, and do not take more than one dose in 24 hours [4]. The effects can last up to 36 hours, so you do not need to time it precisely. For daily tadalafil (2.5mg or 5mg), take one tablet at the same time each day, whether or not you plan to have sex [4].

Continue taking your dolutegravir and other HIV medicines exactly as prescribed by your HIV specialist. Do not skip doses or change the timing of your antiretrovirals to fit around tadalafil, as this can affect how well your HIV treatment works. Tadalafil can be taken with or without food, and it does not need to be taken at the same time as dolutegravir—there is no need to separate the doses.

Avoid drinking large amounts of alcohol when taking tadalafil, as alcohol can make erectile dysfunction worse and increase the risk of side effects such as dizziness, headache, and low blood pressure [4]. Grapefruit juice can also raise tadalafil levels in the blood, so it is best to avoid it. If you experience any side effects or have concerns about your treatment, speak to your prescriber or pharmacist for advice.

When to Seek Urgent Help with Tadalafil and Dolutegravir

Most men tolerate tadalafil well, but it is important to know the warning signs that need urgent medical attention. If you develop an erection that lasts longer than four hours (priapism), go to A&E immediately or call 999 [3][4]. Priapism is a medical emergency that can cause permanent damage to the penis if not treated promptly. Do not wait to see if it goes away on its own.

Seek urgent help if you experience sudden loss of vision in one or both eyes, as this can be a sign of a rare but serious condition called non-arteritic anterior ischaemic optic neuropathy (NAION) [3][4]. Similarly, if you have sudden hearing loss or ringing in the ears, stop taking tadalafil and see a doctor as soon as possible. If you develop chest pain during or after sexual activity, stop and seek medical advice—do not take nitrate medicines such as GTN spray, as the combination with tadalafil can be dangerous [4].

If you experience severe dizziness, fainting, or signs of an allergic reaction (such as swelling of the face, lips, or throat, or difficulty breathing), call 999 or go to A&E immediately. These are rare but serious side effects that need urgent treatment. For less urgent concerns, such as persistent headaches or indigestion, speak to your prescriber or pharmacist, who can advise whether any adjustments to your treatment are needed.

Monitoring Your HIV Treatment

Continue to attend all your scheduled appointments with your HIV specialist and have regular blood tests to monitor your viral load and CD4 count. Starting tadalafil should not affect your HIV treatment, but it is important to keep your specialist informed about any new medicines you are taking, including treatments for erectile dysfunction. If you have any concerns about how your medicines are working together, your HIV specialist or pharmacist can provide reassurance and advice.

In summary

• No major interaction between tadalafil and dolutegravir is commonly reported.
• Your prescriber reviews all your HIV medicines to ensure tadalafil is safe for you.
• Boosted regimens with ritonavir or cobicistat may require a lower tadalafil dose.
• Continue taking your HIV medicines exactly as prescribed—do not skip doses.
• Seek urgent help for an erection lasting over four hours or sudden vision loss.

Choose your treatment

Select from our recommended UK-licensed medications.

Answer quick questions

Select safe UK treatments. Quick answers.

Get it delivered fast

We will deliver direct to you as quickly as tomorrow.

Faq