ED Pills and Blood Pressure Medication: What Is Safe

Sildenafil and tadalafil work by relaxing the smooth muscle in blood-vessel walls so the penis can fill. That same relaxation happens, to a smaller degree, in vessels all over the body, which is why these drugs lower blood pressure a little in everyone. On their own that is harmless for most men. The risk arrives when they are combined with a drug that lowers blood pressure through the same pathway, or with several that lower it through different ones. The labels, summarised in the sildenafil and tadalafil MedlinePlus monographs, sort the combinations into three tiers.

Both labels list these as contraindications, which is the strongest language a label uses:

• Nitrates - nitroglycerin in every form (tablets under the tongue, sprays, patches, ointment, long-acting capsules), isosorbide mononitrate and isosorbide dinitrate. These are angina medicines, so they turn up in men with heart disease.
• Recreational nitrites - amyl nitrite, butyl nitrite, "poppers". The MedlinePlus sildenafil page specifically warns about street drugs containing nitrates.
• Riociguat, used for pulmonary hypertension.

The mechanism is additive and large: both sides push the same signalling pathway, and the resulting fall in blood pressure can be severe enough to cause fainting, a heart attack or a stroke. There is no safe dose of either drug in this combination.

The labels also address the emergency case. If a man who has taken an ED drug develops chest pain and a nitrate would normally be given, it should be withheld for at least 24 hours after sildenafil and at least 48 hours after tadalafil, and then given only under close monitoring. If you ever go to an emergency room with chest pain, say when you last took your ED medication. It is not a cause for embarrassment; it is information that can save your life.

Alpha-blockers - doxazosin, terazosin, prazosin, and the prostate-focused tamsulosin, alfuzosin and silodosin - lower blood pressure, and some men take them for an enlarged prostate rather than hypertension. The labels allow combining them with a PDE5 inhibitor, with two conditions:

• The man should be on a stable dose of the alpha-blocker before the ED drug is added, so that the combined effect lands on a known baseline.
• The ED drug should be started at its lowest dose - 25 mg for sildenafil - and raised only if tolerated.

The thing to watch for is dizziness or light-headedness on standing, especially in the hours after a dose. Spacing the two drugs apart in the day is something some clinicians suggest; follow whatever your prescriber says rather than improvising.

Most men with high blood pressure are on drugs from other classes: ACE inhibitors (lisinopril, enalapril and others ending in -pril), ARBs (losartan, valsartan and others ending in -sartan), calcium-channel blockers (amlodipine and others), beta-blockers (metoprolol, atenolol, bisoprolol), and thiazide diuretics. The prescribing information reports that sildenafil taken alongside such drugs produces only a small additional drop in blood pressure beyond the drug alone, and these combinations are used routinely. The clinician still wants to know, because a man on three antihypertensives who also drinks has more room to feel dizzy than a man on one.

Two further things the labels flag are worth raising at intake: drugs that raise PDE5-inhibitor blood levels (certain antifungals, HIV protease inhibitors, some antibiotics), which may call for a lower starting dose; and the alcohol warning on the tadalafil label, since a substantial amount of alcohol with tadalafil can itself cause dizziness and a drop in standing blood pressure.

There is a second link between blood pressure and ED: some of the drugs that treat hypertension are on the NIDDK's list of medications that can cause ED, and high blood pressure itself damages the arteries an erection needs. If ED began after a blood-pressure medication was started or changed, that is worth telling the prescriber. The right response is almost never to stop the drug - uncontrolled hypertension does far more damage to erections and everything else - but often a switch within the same class, or to a different class, solves the problem. Our guide to what causes ED covers the medication causes alongside the rest.

Every licensed online clinic asks for a medication list, and this is the page where it matters most. List everything: prescription drugs, the as-needed nitroglycerin you keep in a drawer, over-the-counter products, supplements and anything recreational. The clinician cannot screen for what is not written down. Our walkthrough of how to get ED treatment online covers the rest of the process, and the clinics in our ED treatment comparison all run that review before anything is prescribed. If a clinic does not ask about your medications, that is the moment to leave; our guide to buying ED medication online safely explains why.

This article is general information, not medical advice. Do not start, stop or change any medication without a licensed clinician who knows your full health history.