Tadalafil and Levofloxacin: Can You Take Them Together?
UK pharmacist advice on this antibiotic interaction and what your prescriber checks for safe use.
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Tadalafil and Levofloxacin: Understanding the Interaction
Published: 22 October 2026
Many men wonder whether tadalafil and levofloxacin can be taken together safely. The good news is that no major direct interaction is commonly reported between tadalafil (a medicine for erectile dysfunction) and levofloxacin (an antibiotic). However, both medicines can affect your heart rhythm and blood pressure, so your prescriber will carefully review your medical history and current health before confirming that the combination is suitable for you.
Always declare all your medicines
During your online consultation, list every medicine you are taking, including antibiotics, over-the-counter products, and supplements. This helps the prescriber make a safe, informed decision tailored to your health.
What is tadalafil and levofloxacin used for?
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 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 lower daily dose (2.5 mg or 5 mg) for continuous treatment. It is the active ingredient in branded Cialis and is also available as a generic medicine.
Levofloxacin is a fluoroquinolone antibiotic prescribed to treat bacterial infections, including respiratory tract infections (such as pneumonia and bronchitis), urinary tract infections, skin infections, and some sexually transmitted infections [12]. It works by killing bacteria or stopping them from multiplying. Levofloxacin is usually taken as a tablet once or twice daily for a course of 5 to 14 days, depending on the type and severity of the infection. It is a prescription-only medicine and should only be used when your doctor has confirmed a bacterial infection that requires this specific antibiotic.
Is there an interaction between tadalafil and levofloxacin?
No major direct drug interaction is commonly reported between tadalafil and levofloxacin, meaning they do not directly interfere with each other's breakdown or effectiveness in the body [3][4][12]. However, both medicines can have effects on the cardiovascular system that your prescriber must consider. Tadalafil can cause a small drop in blood pressure, which is usually well tolerated but may cause dizziness or light-headedness in some men. Levofloxacin, like other fluoroquinolone antibiotics, has been associated (rarely) with changes in heart rhythm, including a condition called QT prolongation, which can increase the risk of serious irregular heartbeats.
Because of these individual effects, your prescriber will check your full medical history, including any heart conditions, blood pressure problems, or medicines that might also affect heart rhythm or blood pressure. If you have a history of heart rhythm disturbances, low blood pressure, or are taking other medicines that prolong the QT interval, your doctor may decide to monitor you more closely or adjust your treatment. It is essential that you declare all your current medicines and health conditions during your online consultation, so the prescriber can make a safe decision tailored to you.
What your prescriber checks
During your consultation, the prescriber will ask about your heart health, blood pressure, any history of fainting or irregular heartbeats, and all medicines you are currently taking (including over-the-counter and herbal products). They will also check whether you have any kidney or liver problems, as both tadalafil and levofloxacin are processed by these organs. If you are prescribed both medicines, your prescriber may advise starting on a lower dose of tadalafil, avoiding alcohol, and watching for any unusual symptoms such as dizziness, palpitations, or chest discomfort.
When to get urgent help
- Erection lasting more than 4 hours (priapism) – go to A&E immediately
- Sudden loss of vision or hearing – stop the medicine and seek urgent medical help
- Chest pain during sex or severe dizziness – call 999 or go to A&E
- Fast or irregular heartbeat, fainting, or severe palpitations – seek same-day medical advice
- Allergic reaction (rash, swelling, difficulty breathing) – call 999 if severe
Call 999 or go to A&E in an emergency, or contact NHS 111 for urgent advice.
How tadalafil and levofloxacin work in your body
Tadalafil works by blocking an enzyme called phosphodiesterase type 5 (PDE5), which normally breaks down a substance that relaxes smooth muscle in blood vessels. By inhibiting PDE5, tadalafil helps blood vessels in the penis to widen and fill with blood during sexual arousal, making it easier to get and keep an erection [3][4]. Tadalafil also has a mild blood-pressure-lowering effect throughout the body, which is why it can cause light-headedness in some men, especially when standing up quickly or when combined with alcohol or other blood-pressure medicines.
Levofloxacin works by interfering with bacterial DNA, preventing bacteria from replicating and repairing themselves, which kills the infection [12]. It is absorbed quickly from the gut and distributed throughout the body, including into tissues and fluids where bacteria may be present. Levofloxacin is mainly eliminated by the kidneys, so dose adjustments may be needed if you have reduced kidney function. While levofloxacin does not directly affect the enzymes that break down tadalafil, it can (rarely) affect the electrical activity of the heart, which is why prescribers consider your overall cardiovascular health when you are taking both medicines together.
Practical advice when taking tadalafil and levofloxacin together
If your prescriber has confirmed it is safe for you to take tadalafil and levofloxacin together, follow the dosing instructions for each medicine carefully. Take levofloxacin at the same time each day (or as directed) with a full glass of water, and complete the full course even if you start to feel better, to ensure the infection is fully cleared. Tadalafil on-demand tablets should be taken at least 30 minutes before sexual activity (effects can last up to 36 hours), or if you are on a daily dose, take it at the same time each day regardless of when you plan to have sex [4].
Avoid drinking large amounts of alcohol while taking either medicine, as alcohol can worsen erectile dysfunction, increase the risk of dizziness and low blood pressure, and may reduce the effectiveness of the antibiotic. Stay well hydrated, especially while taking levofloxacin, to help your kidneys clear the medicine. If you experience dizziness, stand up slowly from sitting or lying down. Do not drive or operate machinery if you feel light-headed or unwell. If you develop any unusual symptoms such as a fast or irregular heartbeat, chest pain, fainting, severe dizziness, or sudden vision or hearing changes, stop taking the medicines and seek urgent medical advice.
When to contact your doctor
Contact your GP or prescriber if you experience persistent or severe side effects from either medicine, including ongoing dizziness, palpitations, muscle or joint pain (a known side effect of fluoroquinolones), or any allergic reaction such as rash, swelling, or difficulty breathing. If you have an erection lasting more than four hours (priapism), sudden loss of vision or hearing, or chest pain during sexual activity, seek emergency medical help immediately by calling 999 or going to A&E [1][4].
At a glance
Other medicines and health conditions to consider with tadalafil and levofloxacin
Tadalafil must never be taken with nitrates (such as GTN spray, isosorbide mononitrate or dinitrate), nicorandil, riociguat, or recreational drugs called 'poppers' (amyl or alkyl nitrites), as the combination can cause a dangerous drop in blood pressure [3][4]. Do not take tadalafil with another PDE5 inhibitor (sildenafil, vardenafil, or avanafil). If you are taking alpha-blockers for prostate symptoms or high blood pressure (such as tamsulosin, doxazosin, or alfuzosin), you should be stable on the alpha-blocker before starting tadalafil, and your prescriber will usually recommend starting on the lowest dose of tadalafil to reduce the risk of dizziness.
Levofloxacin should be used with caution if you are taking other medicines that can prolong the QT interval (such as certain antidepressants, antipsychotics, or heart rhythm medicines), corticosteroids (which increase the risk of tendon problems), or medicines that affect kidney function. Some antacids, iron supplements, and dairy products can reduce the absorption of levofloxacin, so take the antibiotic at least two hours before or after these products [12]. Always tell your prescriber about all your current medicines, including over-the-counter products, vitamins, and herbal supplements such as St John's wort, which can reduce the effectiveness of tadalafil.
Getting tadalafil and levofloxacin safely in the UK
Levofloxacin is a prescription-only antibiotic and will be prescribed by your GP or another healthcare professional if you have a confirmed bacterial infection that requires this specific treatment. Tadalafil is also a prescription-only medicine for erectile dysfunction, and at Cured Pharmacy, it is supplied following an online consultation reviewed by a UK-registered prescriber [4]. During the consultation, you will be asked detailed questions about your medical history, current medicines (including any antibiotics), and any symptoms or health conditions. The prescriber will check that tadalafil is safe and suitable for you, taking into account any other medicines you are taking, including levofloxacin.
If the prescriber approves your request, your tadalafil will be dispensed by our GPhC-registered pharmacy (GPhC 9012511) and delivered discreetly to your door. Cured Pharmacy offers 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. All our prescription medicines are genuine, UK-licensed products, and our service is designed to be convenient, confidential, and led by experienced healthcare professionals. If you have new or worsening erectile dysfunction, we encourage you to see your GP, as ED can be an early sign of underlying health conditions such as heart disease or diabetes [1][2].
Why choose Cured Pharmacy
Cured Pharmacy is a fully registered online pharmacy (GPhC 9012511) offering convenient, confidential access to genuine ED treatments. Our online consultations are reviewed by UK-registered prescribers, and all medicines are dispensed by qualified pharmacists. We provide clear, honest information, discreet packaging, and fast delivery, so you can access the treatment you need with confidence and peace of mind.
In summary
- No major direct interaction is commonly reported between tadalafil and levofloxacin.
- Both medicines can affect heart rhythm and blood pressure, so prescriber review is essential.
- Always declare all current medicines during your consultation for a safe, tailored decision.
- Watch for dizziness, palpitations, or chest pain and seek help if symptoms occur.
- Avoid heavy alcohol and stay hydrated while taking both medicines.
Scientific References
- NHS. (n.d.). Erectile dysfunction (impotence). NHS website. https://www.nhs.uk/conditions/erection-problems-erectile-dysfunction/ [accessed 22 October 2026]
- National Institute for Health and Care Excellence. (n.d.). Erectile dysfunction. Clinical Knowledge Summaries. https://cks.nice.org.uk/topics/erectile-dysfunction/ [accessed 22 October 2026]
- Joint Formulary Committee. (n.d.). Sildenafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/sildenafil/ [accessed 22 October 2026]
- Joint Formulary Committee. (n.d.). Tadalafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/tadalafil/ [accessed 22 October 2026]
- Electronic Medicines Compendium. (n.d.). Summaries of Product Characteristics and Patient Information Leaflets. https://www.medicines.org.uk/emc/ [accessed 22 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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Medically reviewed by
Tarun Kumar, Superintendent Pharmacist (GPhC 2233073)