Vardenafil and Rifabutin: Can They Be Taken Together?

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At a glance

What Is Vardenafil and How Does It Work?

Vardenafil (also known by the brand name Levitra) is a prescription medicine used to treat erectile dysfunction in men [5]. 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're sexually aroused. Vardenafil does not cause an erection on its own – sexual stimulation is still needed for it to work.

Vardenafil is available in 5mg, 10mg, and 20mg tablets and is usually taken about 25 to 60 minutes before sexual activity [5]. The effects can last for several hours, though this varies between individuals. Like all PDE5 inhibitors, vardenafil should only be taken once in a 24-hour period. It's prescribed after a clinical assessment to ensure it's suitable for you, taking into account your medical history and any other medicines you're taking.

What Is Rifabutin and Why Is It Prescribed?

Rifabutin is an antibiotic that belongs to the rifamycin family of medicines. It's primarily used to prevent or treat mycobacterial infections, particularly Mycobacterium avium complex (MAC) infections in people with HIV or other conditions that weaken the immune system. Rifabutin is also sometimes used as part of combination therapy for tuberculosis, especially when the standard treatment with rifampicin is not suitable.

This medicine works by stopping bacteria from making essential proteins they need to survive and multiply. Rifabutin is usually taken once daily, either as a single dose or divided into smaller doses throughout the day, depending on what it's being used to treat. Because it affects how your liver processes many other medicines, rifabutin can interact with a wide range of drugs, including treatments for erectile dysfunction like vardenafil.

How Do Vardenafil and Rifabutin Interact?

The interaction between vardenafil and rifabutin occurs because rifabutin is what's known as a CYP3A4 inducer. Your liver uses an enzyme system called CYP3A4 to break down many medicines, including vardenafil. Rifabutin speeds up this enzyme system, causing your body to break down vardenafil more quickly than it normally would [5]. This means that vardenafil may not stay in your system long enough or reach high enough levels to be fully effective.

When vardenafil is broken down faster, you may find that it doesn't work as well for treating erectile dysfunction, or that its effects don't last as long as expected. This is different from some other drug interactions where medicine levels become dangerously high – in this case, the concern is reduced effectiveness rather than increased side effects. However, every person responds differently, and the extent of this interaction can vary.

The Role of CYP3A4 Enzymes

CYP3A4 is one of the most important enzyme systems in your liver for processing medicines. Many commonly prescribed drugs are metabolised (broken down) by CYP3A4, which is why interactions involving this enzyme are so common and clinically significant. Medicines that induce or speed up CYP3A4 – like rifabutin, rifampicin, carbamazepine, phenytoin, and the herbal remedy St John's wort – can reduce the effectiveness of other medicines that rely on this enzyme for breakdown. Understanding this mechanism helps explain why your prescriber needs to know about all your medicines, including over-the-counter products and herbal supplements.

What you need to know

• Rifabutin can make vardenafil less effective by speeding up how quickly your body breaks down the ED medicine
• The interaction is not usually dangerous but may mean vardenafil doesn't work as well as expected
• Your prescriber will assess whether vardenafil is suitable and discuss realistic expectations with you
• Never stop rifabutin or increase vardenafil dose without medical advice
• Alternative ED treatments may be available if vardenafil proves ineffective while taking rifabutin

What Your Prescriber Will Check Before Prescribing Vardenafil and Rifabutin

If you're taking rifabutin and request treatment for erectile dysfunction, your prescriber will conduct a thorough review of your medical history and current medicines. They will assess whether vardenafil is likely to be effective given the interaction with rifabutin, or whether an alternative approach might be more suitable. The prescriber will also check that you don't have any conditions that make PDE5 inhibitors unsuitable, such as recent heart attack or stroke, severe heart failure, very low blood pressure, or if you're taking nitrates, nicorandil, or riociguat [5].

Your prescriber may consider several options: they might prescribe vardenafil but explain that it may be less effective than usual; they might suggest a different PDE5 inhibitor that could be more appropriate in your situation; or they might recommend waiting until your rifabutin course is complete if it's a short-term treatment. The decision will be individualised based on your specific circumstances, the reason you're taking rifabutin, how long you'll need it, and your overall health. Always be completely honest about all medicines you're taking, including those prescribed by different doctors, over-the-counter products, and herbal remedies.

Practical Advice for Taking Vardenafil with Rifabutin

If your prescriber decides that vardenafil is appropriate despite the interaction with rifabutin, it's important to have realistic expectations about how well it may work. You might find that the usual dose is less effective than it would be without rifabutin, or that the effects wear off more quickly. Do not increase your dose without consulting your prescriber – taking more vardenafil than prescribed can increase the risk of side effects without necessarily improving effectiveness.

Keep your prescriber informed about how well the treatment is working. If you find vardenafil isn't effective enough, they may be able to adjust your treatment plan. Never take vardenafil more than once in 24 hours, even if you feel it's not working as well as you'd hoped. Remember that all PDE5 inhibitors require sexual stimulation to work, and factors like stress, anxiety, heavy alcohol consumption, and tiredness can all affect how well they work, independently of any drug interaction.

When to Seek Medical Advice

Contact your GP or prescriber if you experience any unexpected side effects while taking vardenafil and rifabutin together, even if you think they're unrelated to the interaction. Common side effects of vardenafil include headache, flushing, indigestion, and nasal congestion, but these should be mild and temporary [5]. If you develop chest pain during sexual activity, stop immediately and seek urgent medical help. Although the interaction between vardenafil and rifabutin typically reduces vardenafil's effectiveness rather than causing dangerous side effects, any new or concerning symptoms should be discussed with a healthcare professional.

When to get urgent help

• Chest pain during or after sexual activity – stop and call 999 immediately
• An erection lasting more than 4 hours (priapism) – go to A&E straight away
• Sudden loss of vision or hearing – seek urgent medical attention
• Severe dizziness, fainting, or signs of very low blood pressure – call 999 or go to A&E
• 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.

Alternative Options for Erectile Dysfunction Treatment

If vardenafil proves ineffective while you're taking rifabutin, several alternatives may be available. Other PDE5 inhibitors – sildenafil (Viagra), tadalafil (Cialis), and avanafil (Spedra) – are also affected by CYP3A4 inducers like rifabutin, though the extent of interaction may vary slightly between them [3][4][6]. Your prescriber can discuss whether switching to a different PDE5 inhibitor might be helpful, or whether it's better to wait until your rifabutin treatment is complete if it's only needed short-term.

For men who cannot use PDE5 inhibitors effectively, other treatment options exist. These include alprostadil, which is available as a cream (Vitaros) applied to the tip of the penis or as an injection (Caverject) into the side of the penis [7]. Vacuum erection devices are non-drug options that can also be effective. Your GP or a specialist can discuss these alternatives with you. It's also worth addressing any underlying causes of erectile dysfunction – managing conditions like diabetes, high blood pressure, or high cholesterol, reducing alcohol intake, stopping smoking, losing weight if needed, and increasing physical activity can all help improve erectile function [1][2].

When Rifabutin Treatment Ends

If you're taking rifabutin for a limited period, vardenafil is likely to become more effective once the rifabutin course is finished. However, rifabutin can continue to affect your liver enzymes for some time after you stop taking it – the inducing effect doesn't disappear immediately. Your prescriber can advise you on when to expect vardenafil to work at its full effectiveness again. If rifabutin is a long-term treatment for you, it's worth having an open conversation with your prescriber about the best ongoing strategy for managing erectile dysfunction, balancing effectiveness, convenience, and your personal preferences.