Tadalafil and Sofosbuvir: Can You Take Them Together?

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At a glance

What Is Tadalafil and What Is Sofosbuvir?

Tadalafil is a 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 is available as the branded medicine Cialis or as generic tadalafil. It can be taken on-demand (10 mg or 20 mg at least 30 minutes before sex, with effects lasting up to 36 hours) or as a lower daily dose (2.5 mg or 5 mg) [4].

Sofosbuvir is an antiviral medicine used to treat chronic hepatitis C infection. It works by blocking a protein that the hepatitis C virus needs to multiply, helping your body clear the infection [12]. Sofosbuvir is usually prescribed as part of a combination treatment regimen and is taken once daily, often alongside other antiviral medicines such as ledipasvir, velpatasvir, or ribavirin. Treatment typically lasts 8 to 24 weeks, depending on your specific hepatitis C genotype and treatment history.

Do Tadalafil and Sofosbuvir Interact?

Based on current evidence, tadalafil and sofosbuvir do not have a significant direct drug interaction. Sofosbuvir is not known to affect the liver enzymes (specifically CYP3A4) that break down tadalafil, and tadalafil does not interfere with how sofosbuvir works against the hepatitis C virus. This means that, in most cases, the two medicines can be prescribed together without one affecting the levels or effectiveness of the other.

However, it is important to remember that sofosbuvir is almost always used in combination with other hepatitis C medicines. Some of these combination partners—particularly certain protease inhibitors or medicines that contain ritonavir or cobicistat—can interact with tadalafil by raising its levels in the blood. Your prescriber will carefully review your complete hepatitis C treatment regimen during your consultation to identify any potential interactions and adjust your tadalafil dose if necessary.

What About Other Hepatitis C Medicines?

If you are taking sofosbuvir alongside other antiviral medicines, your prescriber will check each one. For example, some older hepatitis C protease inhibitors (such as those containing ritonavir or cobicistat) are potent CYP3A4 inhibitors and can significantly increase tadalafil levels, requiring a lower dose or avoidance of tadalafil altogether [4]. Newer combination tablets like sofosbuvir/velpatasvir (Epclusa) or sofosbuvir/ledipasvir (Harvoni) do not typically cause major interactions with tadalafil, but every medicine you take must be declared during your consultation so your prescriber can make an informed decision.

What Your Prescriber Checks Before Prescribing Tadalafil

When you request tadalafil through Cured Pharmacy, a UK-registered prescriber will review your online consultation to ensure the medicine is safe and suitable for you. They will ask about all your current medicines, including sofosbuvir and any other hepatitis C treatments, as well as medicines for other conditions such as high blood pressure, heart disease, or diabetes [2][4]. This is essential because some medicines can interact with tadalafil or make it unsuitable.

Your prescriber will also check your medical history, including any heart problems, recent stroke or heart attack, low blood pressure, liver or kidney disease, and any history of sudden vision or hearing loss. Tadalafil is not suitable for everyone, particularly if you take nitrates (such as GTN spray or isosorbide mononitrate), nicorandil, riociguat, or recreational drugs called 'poppers' (amyl or alkyl nitrites)—these combinations can cause a dangerous drop in blood pressure and you must not take them together [4].

If you have liver disease related to your hepatitis C infection, your prescriber will consider this carefully. Tadalafil is processed by the liver, and people with moderate to severe liver impairment may need a lower dose or may not be suitable candidates for tadalafil at all [4]. Always be honest and thorough when completing your consultation, as this helps your prescriber make the safest decision for you.

What you need to know

• No major direct interaction between tadalafil and sofosbuvir is commonly reported.
• Your prescriber reviews your complete hepatitis C regimen during consultation.
• Some hepatitis C protease inhibitors may require a lower tadalafil dose.
• Never take tadalafil with nitrates, nicorandil, riociguat, or poppers.
• Declare all medicines, including sofosbuvir, when requesting tadalafil.

Practical Advice for Taking Tadalafil with Sofosbuvir

If your prescriber approves tadalafil while you are taking sofosbuvir, follow the dosing instructions carefully. For on-demand tadalafil, take your dose at least 30 minutes before you plan to have sex; the effect can last up to 36 hours, so you do not need to take it every day [4]. If you are prescribed daily tadalafil, take it at the same time each day, regardless of when you plan to have sex. Tadalafil can be taken with or without food, although a very large or high-fat meal may delay how quickly it works.

Continue taking your sofosbuvir and any other hepatitis C medicines exactly as your hepatitis specialist has prescribed. Do not stop or change your hepatitis C treatment without speaking to your specialist, even if you experience side effects. If you are prescribed a new medicine or your hepatitis C treatment changes during your course of tadalafil, inform both your hepatitis specialist and the prescriber at Cured Pharmacy so they can review whether tadalafil remains safe for you.

Avoid drinking large amounts of alcohol while taking tadalafil, as alcohol can worsen erectile dysfunction and increase the risk of side effects such as dizziness, headache, and low blood pressure [4]. Grapefruit juice can also raise tadalafil levels in your blood, so it is best to avoid it. If you experience any new or worsening symptoms—such as severe dizziness, chest pain, or an erection lasting more than four hours—seek medical help immediately.

What If I Experience Side Effects?

Common side effects of tadalafil include headache, indigestion, back pain, muscle aches, flushing, and a stuffy or runny nose [4]. These are usually mild and go away on their own. If side effects are troublesome or persistent, speak to your prescriber—they may be able to adjust your dose. Rare but serious side effects include sudden loss of vision or hearing, chest pain during sex, or a prolonged erection (priapism) lasting more than four hours. If you experience any of these, stop taking tadalafil and seek urgent medical help.

Other Medicines That Can Interact with Tadalafil

In addition to checking your hepatitis C treatment, your prescriber will review all other medicines you take. Tadalafil must never be taken with nitrates (such as GTN spray, isosorbide mononitrate, or isosorbide dinitrate), nicorandil, riociguat, or recreational drugs known as 'poppers'—these combinations can cause a dangerous fall in blood pressure [3][4]. If you take any of these, do not take tadalafil.

Alpha-blockers (such as tamsulosin, doxazosin, or alfuzosin), often prescribed for an enlarged prostate or high blood pressure, can also lower blood pressure when combined with tadalafil, leading to dizziness or fainting. If you take an alpha-blocker, you should be stable on it before starting tadalafil, and your prescriber will usually start you on the lowest dose [4]. Other blood pressure medicines can add to the blood-pressure-lowering effect of tadalafil, so always declare them during your consultation.

Potent CYP3A4 inhibitors—including some HIV medicines (ritonavir, cobicistat), antifungals (ketoconazole, itraconazole), antibiotics (clarithromycin), and COVID-19 treatments such as Paxlovid—can raise tadalafil levels significantly. If you take any of these, your prescriber will reduce your tadalafil dose or may advise against using it [4]. CYP3A4 inducers such as rifampicin, carbamazepine, phenytoin, and St John's wort can reduce tadalafil's effectiveness. Never start, stop, or change any medicine without consulting your prescriber or GP.

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 sex – call 999 or go to A&E
• Severe dizziness or fainting after taking tadalafil – seek same-day medical advice
• Allergic reaction (rash, swelling of face or throat, difficulty breathing) – call 999

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

Getting Tadalafil from Cured Pharmacy

Cured Pharmacy is a GPhC-registered online pharmacy (GPhC 9012511) offering a convenient, confidential service for erectile dysfunction treatment. To request tadalafil, complete a short online consultation that asks about your medical history, current medicines (including sofosbuvir and any other hepatitis C treatments), and general health. A UK-registered prescriber will review your answers to ensure tadalafil is safe and suitable for you. If approved, your medicine is dispensed by our pharmacy team and delivered discreetly to your door.

We offer a range of ED treatments, including generic tadalafil from £7.95 (£6.36 with first-order code Ednew), branded Cialis from £12.00 (£9.60 with code Ednew), and other options such as sildenafil, vardenafil, and avanafil [4][6]. All our medicines are sourced from licensed UK suppliers and meet strict quality standards. If you have any questions about tadalafil and sofosbuvir or your treatment, our pharmacist-led team is here to help.

Remember, erectile dysfunction can sometimes be an early warning sign of underlying health conditions such as heart disease or diabetes [1][2]. If you are experiencing ED for the first time, or if it is getting worse, we encourage you to see your GP for a full assessment. Treating any underlying causes, alongside using ED medication if appropriate, can improve your overall health and quality of life.

Why Choose Cured Pharmacy?

Cured Pharmacy combines clinical expertise with convenience. Every prescription is reviewed by a UK-registered prescriber, and our team of pharmacists is available to answer your questions. We offer fast, discreet delivery, competitive pricing, and a first-order discount (use code Ednew at checkout). Our service is designed to be straightforward, respectful, and supportive, because we understand that discussing erectile dysfunction can feel difficult. You can trust us to provide safe, effective treatment and honest, evidence-based advice.