Tadalafil and Rifabutin: Can They Be Taken Together?

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Tadalafil and Rifabutin: Understanding the Interaction

Published: 25 October 2026

Tadalafil and rifabutin can interact because rifabutin affects how your body processes tadalafil, potentially reducing its effectiveness. Rifabutin is an antibiotic used to treat certain bacterial infections, including tuberculosis and infections in people with weakened immune systems, while tadalafil (Cialis) is a PDE5 inhibitor used to treat erectile dysfunction (ED). Understanding how these medicines interact is important for safe and effective treatment, and your prescriber will carefully review both medications during your consultation to ensure the combination is appropriate for you.

What is Tadalafil and How Does It Work?

Tadalafil is a prescription medicine licensed in the UK to treat erectile dysfunction (ED). 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 for it to work.

Tadalafil is available in two main forms: on-demand tablets (usually 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 every day at the same time [4]. The longer duration of action is why tadalafil is sometimes called the 'weekend pill'. At Cured Pharmacy, tadalafil is available after an online consultation reviewed by a UK prescriber, with generic Tadalafil starting from £7.95 and branded Cialis from £12.00.

Common side effects of tadalafil include headache, indigestion, back pain, muscle aches, flushing, and nasal congestion [4]. These are usually mild and temporary. Tadalafil must never be taken with nitrates, nicorandil, riociguat, poppers, or another PDE5 inhibitor, as this combination can cause a dangerous drop in blood pressure [4].

What is Rifabutin and Why is It Prescribed?

Rifabutin is an antibiotic medicine used to prevent and treat certain bacterial infections, particularly Mycobacterium avium complex (MAC) infections in people with weakened immune systems, such as those with HIV/AIDS. It is also sometimes used as part of combination therapy for tuberculosis (TB), especially when the bacteria are resistant to other antibiotics or when a patient cannot tolerate rifampicin.

Rifabutin works by stopping bacteria from making essential proteins they need to survive and multiply. It is usually taken once daily, either as a single dose or divided into two doses, depending on the condition being treated and other medicines you are taking. Because rifabutin affects how the liver processes many other medicines, it can interact with a wide range of medications, including tadalafil.

Common side effects of rifabutin include nausea, vomiting, changes in taste, skin rash, and discolouration of urine, sweat, or tears (often turning them orange-brown). More serious side effects can include blood disorders and eye inflammation, so regular monitoring is usually needed during treatment. If you are prescribed rifabutin, your doctor will review all your current medicines to check for interactions.

How Rifabutin Affects Other Medicines

Rifabutin is what pharmacists call a 'CYP3A4 inducer'. This means it speeds up the activity of certain liver enzymes (particularly CYP3A4) that break down many medicines in your body. When these enzymes work faster, medicines that rely on them are removed from your bloodstream more quickly, which can make them less effective. This is particularly important for medicines that need to maintain a certain level in your body to work properly, including tadalafil and other PDE5 inhibitors used for erectile dysfunction.

How Tadalafil and Rifabutin Interact

The interaction between tadalafil and rifabutin occurs because rifabutin speeds up the liver enzymes that break down tadalafil. When you take rifabutin regularly, it 'induces' (increases the activity of) the CYP3A4 enzyme system in your liver. Because tadalafil is primarily broken down by this same enzyme system, rifabutin causes tadalafil to be removed from your body more quickly than it would be otherwise.

This faster breakdown means that tadalafil levels in your bloodstream may be lower than expected, which can reduce how well the medicine works for treating erectile dysfunction. The effect is not immediate—it takes several days to weeks of rifabutin treatment for the enzyme induction to reach its maximum effect, and it can take a similar amount of time for the effect to wear off after rifabutin is stopped.

Unlike some other drug interactions that increase the risk of side effects by raising medicine levels, this interaction works in the opposite direction: it may make tadalafil less effective rather than more dangerous. However, this does not mean the combination is risk-free or that you should simply take more tadalafil without medical advice. Your prescriber needs to assess the interaction and determine the most appropriate approach for your individual situation.

What Your Prescriber Will Check

When you request tadalafil through Cured Pharmacy's online consultation, you will be asked to list all your current medicines, including rifabutin. A UK-registered prescriber will review your consultation to check for interactions and ensure tadalafil is safe and appropriate for you. If you are taking rifabutin, the prescriber will consider several factors, including how long you have been taking it, the dose, and whether your rifabutin treatment is short-term or long-term.

The prescriber will also review why you are taking rifabutin, as the underlying condition may itself affect whether tadalafil is suitable. For example, some infections and the treatments used for them can affect your overall health and fitness for sexual activity. The prescriber will check your cardiovascular health, blood pressure, and any other medical conditions or medicines that might interact with tadalafil or affect its safety.

If the prescriber determines that tadalafil is appropriate despite the rifabutin interaction, they may recommend starting with a standard dose and monitoring how well it works, or they may suggest alternative strategies. It is important to be completely honest about all medicines you take, including over-the-counter products and herbal supplements like St John's wort, which can also reduce tadalafil effectiveness. Never stop taking rifabutin or change your dose without consulting the doctor who prescribed it, as this could affect your infection treatment.

Other Medicines That Affect Tadalafil

Besides rifabutin, other CYP3A4 inducers can also reduce tadalafil effectiveness, including rifampicin (a related antibiotic), carbamazepine and phenytoin (used for epilepsy), and the herbal remedy St John's wort. Conversely, potent CYP3A4 inhibitors such as ritonavir, cobicistat, ketoconazole, itraconazole, and clarithromycin can raise tadalafil levels, requiring dose reductions [4]. Your prescriber will check all these potential interactions during your consultation.

Practical Advice for Taking Tadalafil with Rifabutin

If your prescriber approves tadalafil while you are taking rifabutin, it is important to follow their instructions carefully and report back if the medicine does not seem to be working as expected. Because rifabutin may reduce tadalafil's effectiveness, you might find that the usual dose does not produce the desired effect. Do not simply take more tadalafil or take it more frequently than prescribed—this could increase the risk of side effects without necessarily improving effectiveness.

Contact your prescriber if you find tadalafil is not working well. They may consider adjusting the dose, switching to a different PDE5 inhibitor, or exploring alternative ED treatments. Remember that tadalafil requires sexual stimulation to work, and factors such as stress, anxiety, alcohol, and tiredness can all affect erectile function regardless of medication. Heavy alcohol can make ED worse and adds to the blood-pressure-lowering effect of tadalafil, so it is best to limit alcohol intake.

If your rifabutin treatment is temporary (for example, a course lasting several weeks or months), your prescriber may suggest waiting until after you finish the antibiotic before starting tadalafil, or they may recommend trying tadalafil during treatment and reassessing afterwards. Keep all your healthcare providers informed about both medicines—tell your GP or specialist that you are using tadalafil, and tell the prescriber who reviews your ED consultation that you are taking rifabutin. Store both medicines as directed, and check the expiry dates regularly.

Alternative ED Treatments and When to Seek Help

If tadalafil is not effective while you are taking rifabutin, or if the interaction makes tadalafil unsuitable for you, other options may be available. Other PDE5 inhibitors such as sildenafil (Viagra), vardenafil (Levitra), and avanafil (Spedra) are also affected by CYP3A4 inducers like rifabutin, so switching to another oral ED medicine may not solve the problem [3][5][6]. However, your prescriber can discuss the relative merits of each option based on your individual circumstances.

Non-oral treatments for ED include Eroxon, a topical gel medical device available without prescription, and prescription-only options such as Vitaros (alprostadil cream) or Caverject (alprostadil injection) [7]. These treatments work locally rather than being absorbed into the bloodstream in significant amounts, so they are less likely to be affected by rifabutin. Your GP or a specialist can discuss these alternatives if oral medicines are not suitable or effective for you.

It is important to see your GP if you develop new erectile dysfunction, as ED can be an early warning sign of cardiovascular disease or diabetes [1][2]. Seek urgent medical help (call 999 or go to A&E) if you experience an erection lasting more than four hours (priapism), sudden loss of vision or hearing, or chest pain during sexual activity. If you develop side effects from tadalafil such as severe dizziness, fainting, or an allergic reaction (rash, swelling, difficulty breathing), stop taking the medicine and seek medical advice promptly.

Reporting Side Effects and Interactions

If you experience what you think might be a side effect or interaction between tadalafil and rifabutin, report it to your prescriber and consider reporting it via the Yellow Card Scheme at yellowcard.mhra.gov.uk. Reporting helps improve the safety information available about medicines. Keep a record of any symptoms, when they occurred, and what medicines you were taking, as this information can help healthcare professionals assess the situation and advise you appropriately.

Scientific References

1. NHS. (n.d.). Erectile dysfunction (impotence). NHS website. https://www.nhs.uk/conditions/erection-problems-erectile-dysfunction/ [accessed 25 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 25 October 2026]
3. Joint Formulary Committee. (n.d.). Sildenafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/sildenafil/ [accessed 25 October 2026]
4. Joint Formulary Committee. (n.d.). Tadalafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/tadalafil/ [accessed 25 October 2026]
5. Joint Formulary Committee. (n.d.). Vardenafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/vardenafil/ [accessed 25 October 2026]
6. Joint Formulary Committee. (n.d.). Avanafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/avanafil/ [accessed 25 October 2026]
7. Joint Formulary Committee. (n.d.). Alprostadil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/alprostadil/ [accessed 25 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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