Is ED Medication Safe for You? Nitrates, Heart Health and Interactions

Most of the safety questions around erectile dysfunction medicine come back to one organ: the heart. Sex is physical activity, and the medicines used for ED relax blood vessels. For most men that combination is fine. For a smaller group, it is not, and the difference usually comes down to a handful of medicines and heart conditions that a physician needs to know about before anything is prescribed. This guide walks through those situations so you know what to mention and what to watch for.

The one rule that has no exceptions: nitrates

Tadalafil must never be taken with any organic nitrate. Nitrates are medicines used mainly for chest pain (angina), and they come as tablets, sprays, patches and under-the-tongue doses. Both nitrates and tadalafil widen blood vessels through the same chemical pathway, and taken together they can drop blood pressure suddenly and dangerously [1].

The same warning covers recreational "poppers" (amyl or butyl nitrite). They are inhaled nitrites that act like nitrates on blood vessels, and combining them with ED medicine carries the same risk of collapse [1][2].

Because tadalafil stays in the body for a long time (its average half-life is about 17.5 hours), the label says that if a nitrate becomes medically necessary, at least 48 hours should pass after the last tadalafil dose, and it should then be given under medical supervision [1]. If you ever have chest pain and call for emergency help, tell the responders that you take tadalafil so they can choose a safe treatment.

Riociguat, a medicine for certain types of pulmonary hypertension, is also contraindicated with tadalafil for the same blood pressure reason [1].

Heart conditions that need a closer look first

The tadalafil label notes that it has not been studied in men with several recent or unstable heart and circulation problems, and it is not recommended for them [1]:

• a heart attack in the last 90 days
• unstable angina, or angina that comes on during sex
• moderate or worse heart failure in the last 6 months
• an uncontrolled heart rhythm problem
• very low blood pressure (below 90/50) or uncontrolled high blood pressure
• a stroke in the last 6 months

It also advises caution in men with conditions that restrict blood flow out of the heart, such as aortic stenosis [1]. More broadly, ED medicine is not appropriate for any man whose doctor has advised that sexual activity is unsafe for his heart.

How physicians judge whether sex is safe for your heart

The Princeton III consensus, a set of recommendations from cardiologists and urologists, suggests sorting men into risk groups before treating ED [3]. Men at low cardiovascular risk can usually be treated. Men at intermediate risk benefit from further evaluation first, such as an exercise test. Men at high risk should hold off on both sexual activity and ED treatment until their heart condition is stable. A rough everyday guide used in this setting is whether you can manage moderate exertion, such as climbing a couple of flights of stairs briskly, without chest pain or severe breathlessness. Your physician will ask about this in your assessment.

ED can itself be an early warning sign of narrowed arteries, so a new erection problem is also a reason to check blood pressure, cholesterol and blood sugar. Our guide to ED and heart health covers this in more detail.

Blood pressure medicines and alpha-blockers

Tadalafil lowers blood pressure slightly on its own. Added to medicines that also lower it, the effect can stack up and cause dizziness or fainting [1]. This matters most with alpha-blockers, which are prescribed both for high blood pressure and for urinary symptoms from an enlarged prostate. They are not automatically off limits, but the physician needs to know about them, and the starting plan may be more cautious.

Apomorphine adds a second blood pressure consideration. At the higher doses used for other conditions, its labels warn that blood pressure medicines and vasodilators, including nitrates, can deepen the drop in blood pressure it causes [4].

A specific warning for anti-nausea medicines

Apomorphine has one interaction that surprises many people. A class of anti-nausea drugs called 5-HT3 antagonists (ondansetron, granisetron, dolasetron, palonosetron and alosetron) is contraindicated with apomorphine, because the combination has caused profound low blood pressure and loss of consciousness [4]. These drugs are commonly given in emergency rooms, after surgery, during chemotherapy and for stomach bugs. If one is offered to you while you are taking an apomorphine-containing medicine, mention it to the clinician first.

Medicines that change how tadalafil is handled

Tadalafil is broken down in the liver by an enzyme called CYP3A4. Some medicines block that enzyme and raise tadalafil levels, including the antifungals ketoconazole and itraconazole and the HIV medicine ritonavir. With a strong blocker on board, the label caps once-daily tadalafil at 2.5 mg [1]. Other medicines speed the enzyme up, such as the antibiotic rifampin, and can make tadalafil less effective. Grapefruit juice can also affect this enzyme, so it is worth mentioning if you drink it often.

People with severe kidney problems should not take tadalafil once daily, according to its label [1].

Alcohol

Alcohol does not change tadalafil levels in the blood, but heavy drinking (around five or more units) alongside tadalafil can lower blood pressure, causing dizziness, a fast heartbeat or a headache [1]. Apomorphine labels also advise against alcohol because it adds to the blood pressure effect [4]. Moderate drinking, and getting up slowly if you feel lightheaded, is a sensible approach. Alcohol also affects erections directly, which our lifestyle guide explains.

What to tell the physician before treatment

A clear, complete medical history is the main thing that keeps ED treatment safe. In your assessment, include:

• every prescription medicine, including anything taken only occasionally, such as chest pain sprays
• recreational drugs, especially poppers
• heart conditions, past heart attacks, stents, strokes or heart failure, with dates
• your usual blood pressure, if you know it, and whether you have ever fainted
• kidney or liver disease
• eye conditions, especially any past sudden vision loss
• supplements and "natural" sexual enhancement products, which have sometimes been found to contain hidden prescription drugs

If anything on this list changes after you start treatment, such as a new heart diagnosis or a new prescription, message your care team before your next dose.

When to stop and get help right away

Treat the following as emergencies and call 911 or go to an emergency department:

• chest pain, pressure or a racing heartbeat during or after sex (and do not take a nitrate unless a clinician who knows about your tadalafil tells you to)
• an erection that lasts longer than four hours, painful or not
• sudden loss of vision in one or both eyes
• sudden decrease or loss of hearing, especially with ringing or dizziness
• fainting, or feeling close to fainting

For milder problems, our guide to side effects explains what is common, what usually settles and when to message the care team.

Sources

1. Tadalafil US prescribing information (DailyMed, revised 2026)
2. Tadalafil patient information (generic)
3. Nehra A, et al. The Princeton III Consensus recommendations. Mayo Clin Proc, 2012
4. Apomorphine sublingual film prescribing information (FDA, 2020)
5. NIDDK. Symptoms and causes of erectile dysfunction
6. Thompson IM, et al. Erectile dysfunction and subsequent cardiovascular disease. JAMA, 2005

Related reading

• ED and heart health: why erection problems can be an early sign of narrowed arteries.
• Side effects of tadalafil and apomorphine: what is common, what is rare and what to do about each.
• How tadalafil works: the medicine, its dosing and what the trials show.
• What apomorphine is: a different, brain-based approach to erections.
• The tadalafil and apomorphine combination: the reasoning behind it and what is still unknown.

This article is for education only and is not a substitute for professional medical advice. Do not start, stop or change a medication without speaking to a licensed clinician. If you have chest pain, an erection lasting more than four hours, or sudden loss of vision or hearing, seek emergency care.