Does Tadalafil Lower Blood Pressure? What the Label and Trials Report

Label figures for healthy men, a 114-person hypertension trial, drug-by-drug interaction data, and the combinations that need a prescriber.

Tadalafil lowers blood pressure a little in most men and by more in some. In healthy men, the Cialis label reports that a 20 mg dose produced no significant difference from placebo in supine blood pressure (a difference in the mean maximal decrease of 1.6/0.8 mm Hg).¹ In men with hypertension, a placebo-controlled trial found an average 26-hour drop of 4.8/2.9 mm Hg after a single 20 mg dose.² Combining tadalafil with nitrates is contraindicated, and caution is advised with alpha-blockers, other blood pressure medicines and heavy drinking.¹

How much does tadalafil lower blood pressure in healthy men?

Very little. Tadalafil blocks the PDE5 enzyme, which widens blood vessels, so a small effect on blood pressure is expected. The label's figures for 20 mg in healthy men are a mean maximal decrease in supine blood pressure that differed from placebo by 1.6/0.8 mm Hg, and in standing blood pressure by 0.2/4.6 mm Hg. There was no significant effect on heart rate.¹

A safety review of more than 4,000 men given tadalafil across more than 60 studies reached a similar view: in healthy subjects the changes were small and not believed to be clinically relevant, and daily 20 mg for 26 weeks in healthy men or men with mild ED produced blood pressure changes similar to placebo.³ The label reports the manufacturer's own studies, so it is useful but not independent.

What happens in men who already have high blood pressure?

The drop is larger and shows up on 24-hour monitoring. In a randomized, double-blind, placebo-controlled crossover study of 114 people with hypertension, a single 20 mg dose lowered mean ambulatory blood pressure by 4.8 mmHg systolic and 2.9 mmHg diastolic compared with placebo. In the subgroup still above target on two to four classes of blood pressure medicine, the average fall was 7.5 mmHg systolic and 4.3 mmHg diastolic.²

That is not a treatment effect to rely on. The study was a single dose, tadalafil is not approved to treat hypertension, and a man whose pressure is poorly controlled has a reason to see the prescriber about his blood pressure regardless. The numbers do explain why the label tells prescribers to discuss the possibility of added blood pressure lowering with patients taking antihypertensives.¹

Does it matter which blood pressure medicine a man takes?

The label lists interaction studies by drug, each comparing tadalafil with placebo in men already on the medicine. The average extra reduction in blood pressure was:

With 20 mg and amlodipine, the label found no clinically significant differences from placebo.¹ Measurement methods differ between rows, so the table is not a ranking of drugs. It shows the range a prescriber would expect: a few mm Hg for most men, and somewhat more for some combinations. Our page on ED and blood pressure medicines covers the reverse question, whether the blood pressure drug itself affects erections.

Is tadalafil safe with alpha-blockers?

This is the combination with the strongest warning. Alpha-blockers (such as tamsulosin and doxazosin, often prescribed for prostate symptoms) are also vasodilators, and the label notes that together the two classes can lower blood pressure significantly and may cause symptomatic hypotension such as fainting. It does not recommend tadalafil with alpha-blockers for BPH, and advises caution in men taking them for ED.¹

A pair of studies in healthy men gives a sense of scale. Men took tadalafil 5 mg daily or placebo with rising doses of doxazosin (up to 4 mg) or with tamsulosin 0.4 mg. Mean changes in standing systolic pressure were similar with tadalafil and placebo, but one man on tadalafil plus 4 mg doxazosin had a standing systolic pressure below 85 mm Hg, and three men had moderate hypotensive events, two of them with fainting.⁴ These were healthy men in a controlled setting, so the findings do not cover men with heart disease or low baseline pressure, which is why the prescriber's guidance matters.

What about nitrates and alcohol?

Nitrates are the line that must not be crossed. Tadalafil potentiates the hypotensive effect of nitrates, so Cialis is contraindicated in anyone taking any form of nitrate, including nitroglycerin.¹ In a study of men with chronic stable angina, the maximal fall in standing systolic pressure after nitroglycerin was 36 mm Hg with tadalafil 5 mg and 28 mm Hg with placebo, and more men dropped below 85 mm Hg on the combination.³

Alcohol is a milder vasodilator. The label says that drinking five units or more with tadalafil can increase the chance of lightheadedness, a faster heart rate and a fall in standing blood pressure.¹ See our guide to ED medication interactions for the wider list.

When is low blood pressure a warning sign?

Dizziness on standing, fainting, or a pounding heartbeat after a dose should be treated as a reason to stop and call the prescriber. Chest pain after sex or after taking the drug is an emergency. A man who has had a recent heart attack or stroke, has unstable angina, or has low resting blood pressure should have the dose decision made by a clinician, because the label's cautions on cardiovascular status apply.¹ The common headache, flushing and nasal congestion are also vasodilator effects and are covered in tadalafil side effects.

Limits of the evidence

The best data are short, and much of it comes from the manufacturer's own studies. They tell us the average effect, not what happens to a man who is also dehydrated, drinking, or on four medicines. A single drop of 5 mm Hg is small on average but not the same for everyone, which is why the first dose of a new combination is best taken with a prescriber's advice and not as an experiment.

Questions readers ask

Does Cialis lower blood pressure?

Slightly. In healthy men the label shows no significant difference from placebo at 20 mg, and in men with hypertension a single 20 mg dose lowered average 26-hour pressure by about 5/3 mmHg.{T}{PATTERSON}

Can I take tadalafil with blood pressure medicine?

Often yes, under a prescriber, because the extra drop in the label studies was a few mm Hg. The label advises discussing the added blood-pressure-lowering effect with the prescriber.{T}

Is tadalafil safe with tamsulosin?

The label advises caution with alpha-blockers. In a study of healthy men, tadalafil 5 mg with tamsulosin 0.4 mg was well tolerated, but that does not cover every man.{T}{GUILLAUME}

Does tadalafil cause low blood pressure?

It can, mainly with nitrates, alpha-blockers, heavy drinking or low baseline pressure. Nitrates are contraindicated.{T}

Can tadalafil be used to treat high blood pressure?

No. Its blood pressure effect is a side effect of how it works, not a reason to take it for hypertension.{T}

Further reading

Part of our guide: How ED Medications Work: Timing, Food, Interactions and Combinations

• Sildenafil Headache: How Common Is It?
• Tadalafil With Alcohol: How Much Is Too Much?
• What Is Tadalafil Used For? The Three Approved Uses
• Tadalafil Brand Names: Which Brand Is Used for What