Cialis (tadalafil) is a medication that is used by men with erectile dysfunction to help them get and keep erections during sexual intercourse. It works by allowing greater blood flow to the penis. It is also used for benign prostatic hypertrophy (BPH), also known as “enlarged prostate,” which includes symptoms such as difficulty urinating, having a weak urine stream, and needing to urinate frequently, even at night when you would normally be sleeping (per Mayo Clinic). Cialis’ mechanism of action is thought to be that it can relax the smooth muscle in the prostate, bladder, and blood vessels.
However, the relaxation of blood vessel walls can have an additional effect. It can reduce blood pressure. Luckily for men without high blood pressure, this reduction isn’t enough to cause problems. Hims notes that one study found that men taking 20 milligrams of Cialis had a drop in their blood pressure of no more than 1.6 millimeters of mercury in systolic blood pressure and 0.8 millimeters of mercury in diastolic blood pressure when lying down. When standing, these measurements were 0.2 millimeters of mercury and 4.6 millimeters of mercury respectively. That being said, however, Cialis can interact with other medications to cause dangerous drops in blood pressure.
Drugs that interact with Cialis by dropping blood pressure
Drugs.com lists several medications that can interact with Cialis causing blood pressure to fall. They state that combining these with Cialis could lead to dizziness, faintness, heart attack, or stroke.
Nitrates, including the drug nitroglycerin, are used to treat angina, a condition that causes chest, jaw, and arm pain. The drugs isosorbide dinitrate or isosorbide mononitrate also contain nitrates. Additionally, “poppers,” which are used recreationally, can contain nitrates.
Another type of drug that can interact with Cialis is guanylate cyclase stimulators such as riociguat (Adempas). This medication treats high blood pressure in the lungs.
Vasodilators like alpha-blockers should also not be taken with Cialis. These medications are often used to treat BPH.
Also, speak with your doctor if you are using any other medications similar to Cialis such as Viagra (sildenafil), Stendra (avanafil), or vardenafil.
What to do if you accidentally mix Cialis with these drugs
In the event that you do accidentally take one of these medications with Cialis, you may have symptoms of abnormally low blood pressure. Symptoms may include dizziness, fainting, nausea, vomiting, blurred vision, shallow breathing, fatigue, weakness, lethargy, confusion, trouble concentrating, agitation, and behavioral changes. The Cleveland Clinic states that anything below 90/60 millimeters of mercury is considered to be low blood pressure.
If you begin to experience symptoms of very low blood pressure, contact your doctor right away (per Drugs.com). If your blood pressure drops too low, it can even be fatal, according to MercyHealth. They write that cold, clammy, or pale skin; rapid or shallow breathing; weak or rapid pulse; and confusion are all signs of dangerously low blood pressure. They advise calling 911 right away if you are experiencing these symptoms.