Does Cialis Lower Blood Pressure?

Cialis®, known in its generic form as tadalafil, is one of the most commonly prescribed erectile dysfunction medications on the market today. 

While other erectile dysfunction drugs such as Viagra® (sold generically as sildenafil) and Levitra® (sold generically as vardenafil) are taken as needed immediately before sex, tadalafil’s long half-life — the amount of time it takes to eliminate 50 percent of the drug from your system — renders it effective for up to 36 hours. 

Tadalafil can also be taken at a low dose on a daily basis, which allows those on the medication to be ready for sexual encounters as they come up organically, rather than having to take a pill and wait for it to kick in.

But like any other medication, tadalafil can have side effects and may not be right for everybody — particularly those with certain medical conditions or those taking certain medications. 

Below, we’ll talk about how Tadalafil (Cialis) works and the impact it can have on blood pressure.

How Cialis Works

Tadalafil belongs to a class of medications known as phosphodiesterase type 5 inhibitors, or PDE5 inhibitors. 

PDE5 inhibitors are so named because they block an enzyme called cGMP-specific phosphodiesterase type 5 (PDE5) that breaks down cyclic guanosine monophosphate (cGMP), a molecule that relaxes smooth (or involuntary) muscles.

When PDE5 is blocked, cGMP can relax smooth muscles, widen blood vessels and increase blood flow without interference — particularly in the penis and lungs, where PDE5 is highly concentrated. 

This, in turn, makes it easier for the erectile tissue in the penis to become engorged with blood and stiffen, causing an erection.

Cialis’ Effect on Blood Pressure

Because tadalafil and other PDE5 inhibitors have vasodilating effects — meaning they open blood vessels — they make it easier for blood to flow, which can lower blood pressure. 

These decreases in blood pressure are typically temporary and unlikely to cause significant health issues in most patients. 

A clinical study found that healthy men taking 20 mg of Cialis® versus a placebo experienced an average decrease of up to 1.6 Hg in systolic blood pressure and 0.8 mm Hg in diastolic blood pressure when lying down, and 0.2 Hg in systolic blood pressure and 4.6 mm Hg in diastolic blood pressure when standing. 

For context, people may begin to feel negative effects after a sudden blood pressure drop of 20 mm Hg.

Tadalafil can more substantially lower pulmonary blood pressure, or the pressure of the blood flowing in your lungs, because of the lungs’ high concentration of PDE5. 

As a result, tadalafil is sometimes used as a treatment for pulmonary hypertension — or elevated blood pressure in the lungs — under the brand name Adcirca®. It should be noted, though, that pulmonary blood pressure is different than systemic (overall) blood pressure.

While tadalafil by itself isn’t likely to cause a dangerously low drop in systemic blood pressure in healthy men, there are certain medical conditions and drugs that can potentially heighten its hypotensive effects.

Contraindicated Conditions

Patients with the following conditions were not included in clinical safety or efficacy trials, so tadalafil is not currently recommended for them:

• Recent heart attack

• Recent heart failure

• Angina

• Severe, uncontrolled arrhythmia (irregular heartbeat)

• Hypotension (low blood pressure)

• Uncontrolled hypertension 

• Recent stroke

Other groups that tadalafil may not be well suited for include those with:

• Obstructions of outflowing blood from the left ventricle (such as aortic stenosis and idiopathic hypertrophic subaortic stenosis)

• Severely impaired autonomic control of blood pressure

• Not healthy enough for sexual activity

• Bleeding problems or disorders

• Liver problems

• Kidney problems, or those who require dialysis

• Retinitis pigmentosa (a rare genetic eye disease)

• Severe vision loss, including non-arteritic anterior ischemic optic neuropathy (NAION)

• Stomach ulcers

• Penis deformations or Peyronie’s disease

• Priapism (erections lasting more than 4 hours)

• Blood cell problems such as sickle cell anemia, multiple myeloma or leukemia

Contraindicated Drugs

There are also drugs that can increase the hypotensive effects of tadalafil to a dangerous level, including:

• Nitrates, including poppers

• Guanylate cyclase stimulators

• Alpha-blockers

• Antihypertensives

• Other medicines that treat erectile dysfunction

• Substantial amounts of alcohol (5 units [50 millilitres/40 grams at a time] or more)

Signs of Dangerously Low Blood Pressure

Healthcare professionals generally define low blood pressure as anything below 90/60 mm Hg. 

If blood pressure is too low, it can pose serious health risks, such as heart attacks, strokes or shock — insufficient blood flow to the body’s organs and tissues. 

If you experience chest pain, dizziness, or nausea during sex, you should immediately get medical help.

Other indications of dangerously low blood pressure include:

• Fainting

• Dehydration and/or unusual thirst

• Poor concentration

• Blurry vision

• Cold, clammy, and/or pale skin

• Difficulty breathing

• Fatigue

• Depression

If you experience any of these symptoms, you should check in with your healthcare provider.

In Conclusion

While tadalafil does have the potential to lower blood pressure, the effects are typically not cause for concern in healthy men. In certain cases, however, medical conditions and/or drugs can increase tadalafil’s hypotensive effects — sometimes to a dangerous level. 

That’s why it’s so important to discuss your medical history and current medications with your healthcare provider. 

With a robust understanding of your health, your healthcare provider can work with you to find the best erectile dysfunction solution for you.