Tadalafil interacts most dangerously with nitrates, and it also needs caution with alpha-blockers, other blood pressure medications, heavy alcohol, and certain CYP3A4-inhibiting drugs. Because tadalafil relaxes smooth muscle and widens blood vessels, anything else that lowers blood pressure or changes how the liver clears the drug can matter. This guide covers the main tadalafil interactions, what the clinical evidence suggests, and what to tell your clinician before starting.
For background on how the drug works, see our tadalafil mechanism of action explainer. This article focuses only on what not to combine it with.
Can you take tadalafil with nitrates?
No. Nitrates are the one absolute contraindication. Tadalafil (a PDE5 inhibitor) and nitrates both increase nitric oxide signaling, and together they can cause a sudden, severe drop in blood pressure. Product labeling advises avoiding nitrates for at least 48 hours after a tadalafil dose, and a clinician should guide any emergency use.
Which products count as nitrates?
Nitroglycerin (tablets, sprays, patches), isosorbide mononitrate, and isosorbide dinitrate are the common prescription forms. Recreational inhaled nitrites, often called “poppers,” carry the same risk. Anyone who uses nitrates for chest pain should discuss this with a cardiologist before using any PDE5 inhibitor.
Does tadalafil interact with alpha-blockers and blood pressure medications?
It can. Alpha-blockers (used for enlarged prostate or blood pressure) also relax blood vessels, so combining them with tadalafil may cause lightheadedness or low blood pressure on standing. Labeling and clinical studies suggest the combination is manageable for some men at low doses, but it is generally not recommended with certain agents such as doxazosin at higher tadalafil doses. Always disclose alpha-blocker use so your clinician can choose the dose and timing.
Other antihypertensives, including ACE inhibitors, ARBs, and diuretics, usually add a modest additional blood pressure effect. Some patients report mild dizziness when starting. Our guide on tadalafil and blood pressure covers daily-use safety in more detail.
Riociguat, a medication for pulmonary hypertension, is also contraindicated with PDE5 inhibitors.
Is it safe to drink alcohol on tadalafil?
Moderate drinking is generally not considered dangerous on its own, but alcohol and tadalafil both lower blood pressure, and heavy intake may increase dizziness, headache, and fast heart rate. Large amounts of alcohol can also work against erectile function itself. Many clinicians suggest keeping intake light, especially around the time of a dose.
Which drugs and foods change tadalafil levels?
Tadalafil is cleared mainly by the liver enzyme CYP3A4, so medicines that block or boost that enzyme can change how strong and how long the drug acts.
Drugs that may raise tadalafil levels
Strong CYP3A4 inhibitors include ketoconazole, itraconazole, ritonavir and some other HIV protease inhibitors, and clarithromycin. Labeling advises a lower maximum tadalafil dose with these. Large amounts of grapefruit juice may also modestly increase exposure.
Drugs that may lower tadalafil levels
Rifampin and some anticonvulsants (such as carbamazepine and phenytoin) can speed clearance and reduce effect.
Can you combine tadalafil with other ED treatments?
Tadalafil is sometimes prescribed alongside, or compared with, other erectile dysfunction options, but stacking should be clinician-directed. A supervised combination with sildenafil is explained in our sildenafil and tadalafil combination guide. Do not combine PDE5 inhibitors on your own, because overlapping effects raise the chance of side effects.
When should you seek medical help?
Seek urgent care for chest pain, fainting, a prolonged erection lasting more than four hours, or sudden vision or hearing loss while taking tadalafil. Milder effects such as headache, flushing, nasal congestion, back pain, or indigestion are common and often ease over time, but persistent or worsening symptoms deserve a call to your prescriber.
Shift workers and others with irregular schedules sometimes take several medications at different times, which makes interaction checks more important. Keeping one updated medication list, and sharing it at each visit, is a simple safeguard that clinicians widely recommend.
Frequently asked questions
How long after tadalafil can I take nitroglycerin?
Labeling advises at least 48 hours between the last tadalafil dose and any nitrate, unless a physician directs otherwise in an emergency. Because tadalafil lasts much longer than some other PDE5 inhibitors, the waiting period is longer too.
Can I take tadalafil with tamsulosin?
Many men use them together, and tamsulosin has been studied with tadalafil. Still, both can lower blood pressure, so your clinician should confirm the dose and watch for dizziness.
What should I tell my clinician before starting tadalafil?
Share every prescription, over-the-counter product, supplement, and recreational substance you use, plus any history of heart disease, low blood pressure, or liver or kidney problems.
This article is educational and is not medical advice. If you are exploring tadalafil, a licensed clinician can review your medications and history first. Start your RespondWell online visit to see whether tadalafil is appropriate for you.