Tadalafil and Ofloxacin: Can You Take Them Together?
Learn whether these medicines interact and how to use them safely with expert pharmacist guidance.
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Tadalafil and Ofloxacin: Understanding the Interaction
Published: 24 October 2026
Many men wonder whether tadalafil and ofloxacin can be taken together safely. The good news is that no major interaction is commonly reported between tadalafil (a medicine used to treat erectile dysfunction) and ofloxacin (an antibiotic used to treat bacterial infections). However, your prescriber or pharmacist will always review your complete medication list during your consultation to ensure the combination is appropriate for you personally.
Key takeaways
- No major interaction is commonly reported between tadalafil and ofloxacin
- Always declare all medicines during your consultation for a full safety review
- Never take tadalafil with nitrates, nicorandil, riociguat, or poppers
- Some antibiotics like clarithromycin can raise tadalafil levels and need dose adjustment
- Seek urgent help for erections lasting over four hours or sudden vision or hearing loss
What Is Tadalafil and What Does It Do?
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 is the generic version of Cialis and is available in two forms: on-demand tablets (10mg or 20mg taken at least 30 minutes before sex, with effects lasting up to 36 hours) and daily low-dose tablets (2.5mg or 5mg taken once a day) [4].
Tadalafil does not cause an erection on its own—you still need sexual stimulation for it to work [4]. It can help many men achieve and maintain an erection sufficient for sexual activity, but it does not cure ED or increase sexual desire. Because tadalafil affects blood vessels throughout the body, it can interact with certain other medicines, particularly those used to treat heart conditions or high blood pressure [4]. That is why a full medical review is essential before starting treatment.
What Is Ofloxacin and When Is It Prescribed?
Ofloxacin is a prescription antibiotic from the fluoroquinolone family. It is used to treat a range of bacterial infections, including urinary tract infections, respiratory infections, skin infections, and certain sexually transmitted infections [12]. Ofloxacin works by stopping bacteria from multiplying and repairing themselves, which helps your immune system clear the infection more effectively.
Like all antibiotics, ofloxacin should only be used when prescribed by a doctor and taken exactly as directed—even if you start to feel better before finishing the course. Stopping early can allow bacteria to survive and become resistant to treatment. Ofloxacin is not suitable for everyone; your doctor will check your medical history, particularly any history of tendon problems, seizures, or heart rhythm disorders, before prescribing it [12].
At a glance
Can You Take Tadalafil and Ofloxacin Together?
No major interaction is commonly reported between tadalafil and ofloxacin, meaning the two medicines are not known to interfere with each other in a clinically significant way. Ofloxacin does not belong to the groups of medicines that are known to raise tadalafil levels in the blood (such as potent CYP3A4 inhibitors like ketoconazole or ritonavir), nor does it lower blood pressure in a way that would add to tadalafil's effects [4][12].
However, it is essential to declare all medicines you are taking—including antibiotics—when you request tadalafil through an online consultation or from your GP. Your prescriber will review your full medication list, current health conditions, and the reason you are taking ofloxacin to confirm that tadalafil is safe and appropriate for you. Never assume a combination is safe without professional advice, and do not stop or change a prescribed medicine without consulting your doctor or pharmacist.
What Your Prescriber Will Check
During your consultation, the prescriber will ask about your current medicines, allergies, and medical history. They will check that you are not taking any medicines that are contraindicated with tadalafil—such as nitrates (GTN spray, isosorbide mononitrate), nicorandil, riociguat, or recreational drugs known as 'poppers' [3][4]. They will also review whether you have any heart, liver, or kidney problems, and whether the infection you are being treated for (with ofloxacin) affects your suitability for ED treatment. This careful review ensures that both medicines can be used together safely.
How Tadalafil and Ofloxacin Work in Your Body
Understanding how each medicine works can help you use them safely. Tadalafil blocks an enzyme called phosphodiesterase type 5 (PDE5), which normally breaks down a substance that relaxes smooth muscle in blood vessels. By blocking PDE5, tadalafil allows blood vessels in the penis to stay relaxed and open, improving blood flow during sexual arousal [4]. This effect can also cause a small drop in blood pressure throughout the body, which is why tadalafil must not be combined with nitrates or certain other heart medicines [4].
Ofloxacin, on the other hand, works inside bacterial cells by interfering with enzymes the bacteria need to copy and repair their DNA. This stops the bacteria from multiplying and eventually kills them [12]. Ofloxacin does not directly affect blood vessels or the enzymes that break down tadalafil, which is why the two medicines do not have a known major interaction. However, both medicines are processed by your liver and kidneys, so your prescriber will consider your overall health when reviewing the combination.
Always Declare All Medicines
Even if no major interaction is expected, your prescriber must review every medicine you take—including antibiotics, over-the-counter products, and supplements—to ensure tadalafil is safe and appropriate for you.
Practical Advice When Taking Tadalafil and Ofloxacin
If you have been prescribed both tadalafil and ofloxacin, take each medicine exactly as directed. Ofloxacin is usually taken twice a day (or as prescribed) with or without food, and you should complete the full course even if you feel better [12]. Tadalafil on-demand tablets are taken at least 30 minutes before sexual activity, while daily tadalafil is taken once a day at the same time [4]. You can take tadalafil with or without food, though a very heavy or high-fat meal may delay how quickly it works.
Avoid drinking large amounts of alcohol while taking either medicine. Alcohol can make erectile dysfunction worse, increase the risk of side effects such as dizziness or low blood pressure from tadalafil, and may reduce the effectiveness of your antibiotic treatment [1][4]. Stay well hydrated, especially while taking ofloxacin, and avoid excessive sun exposure, as fluoroquinolone antibiotics can make your skin more sensitive to sunlight [12]. If you experience any unexpected symptoms—such as severe dizziness, chest pain, sudden vision or hearing loss, or tendon pain—seek medical advice promptly.
When to Contact Your Doctor or Pharmacist
Contact your doctor or pharmacist if you develop side effects from either medicine that concern you, or if your symptoms do not improve. Common side effects of tadalafil include headache, indigestion, back pain, and flushing [4]. Ofloxacin can cause nausea, diarrhoea, dizziness, or sleep disturbance [12]. Most side effects are mild and temporary, but if you experience an erection lasting more than four hours, sudden loss of vision or hearing, severe skin reactions, or signs of tendon damage (pain, swelling, or difficulty moving a joint), seek urgent medical help.
Other Medicines That Interact With Tadalafil
While tadalafil and ofloxacin do not have a major interaction, tadalafil does interact importantly with several other groups of medicines. You must never take tadalafil with nitrates (such as GTN spray, isosorbide mononitrate, or isosorbide 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 (such as sildenafil or vardenafil) at the same time.
Alpha-blockers (such as doxazosin, tamsulosin, or alfuzosin, often used for prostate symptoms) can also lower blood pressure and may cause dizziness when combined with tadalafil; your prescriber will start you on the lowest dose and ensure you are stable on the alpha-blocker first [4]. Potent CYP3A4 inhibitors—including some HIV medicines (ritonavir, cobicistat), antifungals (ketoconazole, itraconazole), and antibiotics such as clarithromycin—can raise tadalafil levels, requiring dose adjustment [4]. Always declare every medicine, supplement, and herbal product you take during your consultation, so your prescriber can check for interactions and adjust your treatment safely.
Medicines to Declare During Your Consultation
When requesting tadalafil, tell your prescriber about all medicines you take, including over-the-counter products, vitamins, and herbal remedies. Particularly important are any heart or blood pressure medicines, medicines for prostate problems, antifungals, HIV treatments, antibiotics (including ofloxacin), and any medicines for mental health conditions [4]. Also mention if you use St John's wort, as it can reduce the effectiveness of tadalafil. Your prescriber will use this information to confirm that tadalafil is safe for you and to recommend the correct dose.
When to get urgent help
- Erection lasting more than four hours (priapism)—go to A&E immediately
- Sudden loss of vision in one or both eyes—seek urgent medical help
- Sudden decrease or loss of hearing, possibly with ringing in the ears or dizziness
- Chest pain during or after sexual activity—call 999
- Severe tendon pain, swelling, or difficulty moving a joint while taking ofloxacin
Call 999 or go to A&E in an emergency, or contact NHS 111 for urgent advice.
Scientific References
- NHS. (n.d.). Erectile dysfunction (impotence). NHS website. https://www.nhs.uk/conditions/erection-problems-erectile-dysfunction/ [accessed 24 October 2026]
- Joint Formulary Committee. (n.d.). Sildenafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/sildenafil/ [accessed 24 October 2026]
- Joint Formulary Committee. (n.d.). Tadalafil. British National Formulary. NICE. https://bnf.nice.org.uk/drugs/tadalafil/ [accessed 24 October 2026]
- Electronic Medicines Compendium. (n.d.). Summaries of Product Characteristics and Patient Information Leaflets. https://www.medicines.org.uk/emc/ [accessed 24 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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Your Questions Answered
Can't find your answer? Our UK pharmacists review every consultation and can help.
Can I take tadalafil while I'm on a course of ofloxacin?
Yes, no major interaction is commonly reported between tadalafil and ofloxacin. However, you must declare all medicines during your consultation so your prescriber can confirm the combination is safe for you personally.
Will ofloxacin make tadalafil less effective?
No, ofloxacin is not known to reduce the effectiveness of tadalafil. The two medicines work in different ways and do not interfere with each other in a clinically significant manner.
Are there any antibiotics I should avoid while taking tadalafil?
Some antibiotics, such as clarithromycin and erythromycin, can raise tadalafil levels and may require dose adjustment. Always tell your prescriber about any antibiotic you are taking so they can check for interactions.
Do I need to stop tadalafil while taking ofloxacin?
No, you do not usually need to stop tadalafil while taking ofloxacin. Declare both medicines during your consultation, and follow your prescriber's advice on timing and dosing.
Can I drink alcohol while taking tadalafil and ofloxacin together?
It is best to limit alcohol. Heavy drinking can worsen erectile dysfunction, increase the risk of dizziness or low blood pressure from tadalafil, and may reduce the effectiveness of your antibiotic treatment.
What should I do if I experience side effects from either medicine?
Contact your doctor or pharmacist if you develop side effects that concern you. Seek urgent help if you have an erection lasting more than four hours, sudden vision or hearing loss, chest pain, or severe tendon pain.
How long after finishing ofloxacin can I start tadalafil?
If no major interaction is reported, you do not need to wait after finishing ofloxacin to start tadalafil. Your prescriber will review your current health and medication list to confirm suitability.
Will tadalafil affect how well ofloxacin treats my infection?
No, tadalafil does not interfere with the antibacterial action of ofloxacin. Take your antibiotic exactly as prescribed to ensure the infection is treated effectively.
Medically reviewed by
Tarun Kumar, Superintendent Pharmacist (GPhC 2233073)