Does Tadalafil Lower Blood Pressure? A Pharmacist's Safety Guide

Tadalafil, also known under the brand name Cialis, is a medication used to treat erectile dysfunction. It works by relaxing the smooth muscle inside the body’s blood vessels. This is useful for increasing blood flow to the penis and helping men to get and sustain erections, but it can lead to side effects including low blood pressure.

In this article, we’ll explore how tadalafil can lead to low blood pressure, how long the effects last, which medications can make the blood pressure-lowering effects of tadalafil worse, how to avoid this, and when to seek help from a medical professional.

Does Tadalafil Lower Blood Pressure?

Yes, tadalafil can lead to low blood pressure in some situations. Low blood pressure is listed in the medication information leaflet as an uncommon side effect of tadalafil. This means between 1 in 100 and 1000 people who take tadalafil will experience low blood pressure as a result of the medication.

People are more likely to experience low blood pressure if they’re taking tadalafil with medications to control their high blood pressure (also known as hypertension). Low blood pressure is also more likely for people taking medications that can also cause low blood pressure as a side effect, such as nitrates for angina or tamsulosin for an enlarged prostate.

How Does Tadalafil Lower Blood Pressure?

Tadalafil belongs to a class of medications used to treat erectile dysfunction known as phosphodiesterase type-5 (PDE5) inhibitors. They work by blocking PDE5 which stops it from breaking down a chemical known as cGMP.

This leads to higher cGMP levels, helping to relax the smooth muscle found in the body’s blood vessels. By relaxing the blood vessels, more blood can flow out of the arteries and into the penis, helping make it easier to get an erection.

Although PDE5 inhibitors like tadalafil mainly target the blood vessels in the penis and lungs, they also affect other blood vessels in the body. This can lead to relaxation of other blood vessels around the body, lowering your blood pressure.

How Much Does Tadalafil Lower Blood Pressure?

How much tadalafil lowers your blood pressure varies from person to person and depends on the dose tadalafil you take. Blood pressure is measured when the heart is beating (known as systolic blood pressure, the top number in a blood pressure reading) and when the heart is relaxing (known as diastolic blood pressure, the bottom number in a reading). Tadalafil can lower both readings.

One study of 114 people with high blood pressure found that a 20mg dose of tadalafil lowered their average blood pressure over the next 26 hours by 4.8 mmHg (systolic) and 2.9 mmHg (diastolic) compared to people who weren’t taking tadalafil. People taking at least two types of medication for high blood pressure experienced larger effects: an average blood pressure reduction of 7.5 mmHg (systolic) and 4.3 mmHg (diastolic).

Most people don’t notice a small reduction in blood pressure, and a drop in blood pressure doesn’t necessarily mean that your blood pressure is low. Low blood pressure is classed as a reading of less than 90/60mmHg.

However, in some people, a drop in blood pressure can cause symptoms like dizziness or even fainting. People taking blood pressure medication may be more likely to experience symptoms, especially when standing up quickly, as their blood vessels may be less able to adapt quickly.

Tadalafil and Antihypertensive Medications: Safety Guide

People taking medications for hypertension can be more likely to experience a drop in blood pressure after taking tadalafil. However, some medications for high blood pressure are worse than others. Let’s explore each type of medication in more detail.

Tadalafil and Amlodipine

Amlodipine is one of the most common medications for high blood pressure and it belongs to the calcium channel blocker class of drugs.

Taking tadalafil and amlodipine together can increase the risk of experiencing low blood pressure.

A 2022 clinical trial found that tadalafil and amlodipine do interact when taken together, but noted that the 24 trial participants were able to take the medications together without any severe side effects.

In this study, taking both medications together did lower individuals’ blood pressures more than taking either amlodipine or tadalafil alone. However, this reaction wasn’t significant enough for participants to need to stop either medication.

There’s generally no need to reduce the dose of either medication when taking both together, but it’s always best to discuss this with a healthcare professional.

Tadalafil and Beta-Blockers

Beta-blockers are another type of medication used to treat high blood pressure and certain heart problems. Common medications include atenolol, bisoprolol, and metoprolol.

Although in theory taking tadalafil alongside beta-blockers could increase the chance of a reduction in blood pressure, it’s unlikely to pose a serious health risk.

No studies have specifically investigated how tadalafil and beta blockers taken together impact blood pressure. However, a review article analysed the impact of taking tadalafil with various types of high blood pressure medication. This analysis of available clinical trials data found no evidence that taking tadalafil with antihypertensive medications increases the risk of hypotension-related adverse events compared to taking hypertensive medications alone.

Tadalafil and ACE Inhibitors/ARB

Angiotensin-converting enzyme (ACE) inhibitors are another very common class of medication for treating high blood pressure. Common drugs in this category include ramipril and lisinopril.

Angiotensin II receptor blockers (ARB) are another type of antihypertensive that work similarly to ACE inhibitors to block the activity of the blood vessel-narrowing hormone angiotensin. ARB medications include losartan and valsartan.

Similarly to beta-blockers, there have been no specific studies investigating how combining ARBs or ACE inhibitors with tadalafil impacts blood pressure. It’s possible the combination could lower blood pressure slightly.

However, a large analysis of more than 22,000 patients found no increase in negative events linked to low blood pressure when combining tadalafil with various antihypertensives including ARBs and ACE inhibitors.

Tadalafil and Alpha-Blockers (caution required)

Alpha blockers are a type of medication that’s used to treat high blood pressure or an enlarged prostate. Common drugs in this class include doxazosin, alfuzosin, and tamsulosin.

While tadalafil can be taken with alpha blockers, caution is required as combining the two increases the chances of experiencing a sudden drop in blood pressure, especially when standing up after sitting/laying down for a prolonged period of time. Our healthcare professionals will guide you during the consultation and provide you with clinical guidance regarding the dose and timings of when the medications should be taken.

As tadalafil is a long-lasting erectile dysfunction medication, any blood pressure-lowering effects can last for longer than with other shorter-lasting options like Viagra (sildenafil).

Tadalafil and Nitrates: Why It's Dangerous

Nitrates are a type of medication given to widen the blood vessels in people experiencing chest pain from angina and other heart problems. They’re often taken as a spray underneath the tongue, but also come as tablets, creams, and patches.

Although nitrates aren’t taken as a standard high blood pressure treatment, they do have the ability to reduce blood pressure.

Both nitrates and tadalafil work on the same pathway to relax the blood vessel walls, so taking both together can be very dangerous. In combination, the two medications can cause a severe or even life-threatening drop in blood pressure that can lead to collapse, heart attack, stroke, or even death.

Tadalafil should not be taken by anyone who is prescribed nitrates, like glyceryl trinitrate (GTN) spray or isosorbide mononitrate (ISMN) tablets, or who is taking the recreation drugs known as poppers (alkyl nitrites). Speak to our clinicians for tailored clinical guidance if you are taking any nitrates.

Who Should Be Extra Careful?

We’ve already discussed that people taking nitrates should not take tadalafil at all and that those taking alpha blockers like doxazosin should discuss dose adjustments with their prescriber.

Anyone taking the medication riociguat for high blood pressure in the lungs should also be cautious if considering taking tadalafil, as this medication can also increase the chances of a drop in blood pressure. Again, it’s important to discuss this and any other medication you take with a healthcare professional before starting tadalafil.

Tadalafil usually causes only a small extra blood pressure drop when combined with most other antihypertensives, but the risk becomes more important in higher-risk groups.

If you have been known to have episodes of low blood pressure previously or have been diagnosed with orthostatic hypotension, it’s important you watch out for the signs of low blood pressure (like dizziness/light-headedness), especially when standing up.

People who have a history of heart disease, heart failure, a recent heart attack, an irregular heartbeat/arrhythmia that is uncontrolled, or have recently had a stroke are all at higher risk of negative consequences if their blood pressure does drop.

Make sure to speak to a healthcare professional before treatment to make sure it’s safe for you to combine tadalafil with the blood pressure medications you’re taking and any health conditions you have.

When to Talk to Your Doctor

Even if you have been prescribed tadalafil to take alongside your blood pressure medication, it is possible to still experience negative effects.

You should speak to your doctor if you:

• Experience dizziness or near-fainting

• Faint

• Notice a big drop in blood pressure readings compared to normal

• Are prescribed a new medication while in hospital or by a specialist

In an emergency, such as if you lose consciousness for longer than a minute, experience chest pain, shortness of breath, or a weak/irregular pulse, call 999.

Although these symptoms sound worrying, most people are able to safely take tadalafil alongside their high blood pressure medication.

For more advice, speak to your GP or book an online erectile dysfunction consultation with the Quick Meds team to discuss whether it’s safe for you to start tadalafil. Our experienced healthcare professionals are always happy to offer advice and answer your questions. If you’re able to take tadalafil, our team can prescribe it and have it delivered quickly and discreetly to your home or chosen collection point.