When used alone, Cialis (tadalafil) may cause small reductions in blood pressure, but if used with nitrates or guanylate cyclase stimulators like riociguat (brand name: Adempas) your blood pressure may dangerously drop. Do not use these drugs with Cialis. You could get dizzy, faint, or have a heart attack or stroke.

Other drugs or substances that may lower blood pressure when combined with Cialis include alpha blockers, other medicines to treat high blood pressure (hypertension) and use of alcohol.

Cialis is an oral prescription medicine approved for the treatment of:

• erectile dysfunction (ED)
• symptoms of benign prostatic hyperplasia (BPH)
• both ED and BPH

If you develop chest pain, contact your healthcare provider, go to the nearest emergency room, or call 911 right away. Tell all of your healthcare providers that you take Cialis (tadalafil).

Avoid driving or operating hazardous machinery until you know how these medications affect you, and use caution when getting up from a sitting or lying position. In general, your blood pressure should be stable and you should be on a steady dose of one medication before you start the other.

Tell your doctor and pharmacist about all prescription, over-the-counter, herbal, vitamin or recreational drugs you use before starting treatment with Cialis. Other combinations may be unsafe.

Here's more details:

Blood pressure may drop to dangerous levels if Cialis is combined with nitrates. Nitrates are a class of drug which includes medicines like nitroglycerin, isosorbide mononitrate, isosorbide dinitrate or Bidil (isosorbide dinitrate and hydralazine hydrochloride) used for chest pain (angina) or heart failure. Angina is a symptom of heart disease and can cause pain in your chest, jaw, or down your arm.

Nitrates can also include recreational drugs called “poppers” (amyl nitrite and butyl nitrite).

A serious drop in blood pressure can also occur if Cialis is used with a guanylate cyclase stimulator medicine (for example: riociguat [brand name: Adempas], used to treat high blood pressure in the lungs. Do not use nitrates or riociguat if you are also taking Cialis. Ask your doctor or pharmacist if you are not sure if you take any of these medicines.

Cialis may also lead to low blood pressure if used with some alpha-blockers, antihypertensives (blood pressure-lowering medicines) or substantial amounts of alcohol (for example, 5 glasses of wine or 5 shots of whiskey).

Cialis may cause small reductions in blood pressure (7 to 10 mm Hg) when it’s used alone or combined with certain medicines to lower blood pressure (antihypertensives).

Do not use Cialis with other PDE5 inhibitors for erectile dysfunction like Viagra (sildenafil), Stendra (avanafil) or vardenafil.

Low blood pressure with these medicines may occur if you are taking Cialis either as needed for erectile dysfunction (ED) OR once a day for Benign Prostatic Hyperplasia (BPH) and / or ED.

Ask your healthcare provider if it is safe for you to have sexual activity. You should not take Cialis if your healthcare provider has told you not to have sexual activity because of any health problems

For a personalized review of possible drug interactions with Cialis, visit the Drugs.com Drug Interaction Checker and enter your medications. For any questions, ask your healthcare provider..

Which drugs can cause low blood pressure with Cialis?

Nitrates

Nitrates like nitroglycerin are commonly used to treat angina, a symptom of heart disease. Angina symptoms include pain in your chest, jaw, or down your arm. Nitrates are commonly found in medicines that come as tablets, sprays, ointments, pastes, or patches. Do not use Cialis with any nitrate. If you are not sure if a drug is a nitrate, ask your health care provider.

Common brand names of nitroglycerin include:

• Nitro-Dur
• Nitrolingual Pump Spray
• NitroMist
• Nitrostat
• Rectiv

Nitrates can also be found in other medicines such as isosorbide dinitrate (Isordil) or isosorbide mononitrate.

Some recreational drugs called “poppers” also contain nitrates, such as amyl nitrite and butyl nitrite.

If you have taken Cialis, but your doctor decides a nitrate is medically necessary, you must wait at least 48 hours since your last dose of Cialis before nitrate administration can be given by your healthcare provider. Your doctor should monitor your blood pressure under close medical supervision when you receive the nitrate.

Guanylate cyclase stimulators

Do not take Cialis with Adempas or if you take any medicines from a class of drugs called called guanylate cyclase stimulators.

Guanylate cyclase stimulators include a medicine called Adempas (generic name: riociguat), used to treat conditions that cause high blood pressure in the lungs (pulmonary arterial hypertension and chronic-thromboembolic pulmonary hypertension). Do not use Cialis with any guanylate cyclase stimulator.

Ask your healthcare provider or pharmacist if you are not sure if any of your medicines are guanylate cyclase stimulators, such as riociguat.

Vasodilators: Alpha Blockers

If Cialis is taken with certain alpha blockers, your blood pressure could suddenly drop, and you could get dizzy or faint. Alpha blockers can dilate (widen) your blood vessels which may cause low blood pressure. When they are used together, they may cause an additive effect on blood pressure and you may experience very low blood pressure, dizziness or fainting.

Alpha-blockers are sometimes prescribed for prostate problems or high blood pressure and include medicines like Hytrin (terazosin), Flomax (tamsulosin), Cardura (doxazosin mesylate), Minipress (prazosin), Uroxatral (alfuzosin), Jalyn (dutasteride and tamsulosin) or Rapaflo (silodosin).

BPH

Cialis is not recommended for use in combination with alpha-blockers for the treatment of BPH due to the risk of blood pressure lowering.

Patients taking an alpha-blocker therapy for BPH should discontinue their alpha-blocker at least one day prior to starting Cialis for once daily use for the treatment of BPH, under direction from their doctor.

ED

Caution is advised when PDE5 inhibitors are coadministered with alpha-blockers. Patients with ED should be stable on alpha-blocker therapy before starting Cialis, and the lowest recommended dose should be used to start treatment.

If you experience any dizziness, low blood pressure, or fainting while taking these medicines, contact your doctor right away.

Tell your doctor if you take any medicines to lower your blood pressure or to treat BPH or ED, or if you currently use any other PDE5 inhibitor, like Viagra (sildenafil), Stendra (avanafil) or vardenafil; or if you use a drug to treat pulmonary hypertension called Adcirca or Revatio.

Related questions

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Alcohol

You should also avoid drinking too much alcohol when taking Cialis (for example, 5 glasses of wine or 5 shots of whiskey). Drinking excessive alcohol can increase your risk of getting a headache, a fast heart rate, low blood pressure( especially when standing up), dizziness, or fainting.

Alcohol is also a mild vasodilator and can cause low blood pressure.

The amount of alcohol that might cause these side effects could vary between people, so use caution if you combine Cialis with any alcoholic beverages. Ask your doctor if it is safe for you to drink alcohol while taking Cialis.

Antihypertensives (blood pressure medicines)

Using Cialis with blood pressure medicines like amlodipine, angiotensin II receptor blockers (ARBs), bendrofluazide, enalapril, and metoprolol may cause small reductions in your blood pressure, based on studies done by the manufacturer.

For example, one study looked at the interaction of angiotensin II receptor blockers (ARBs), used alone or with other blood pressure medicines, and Cialis 20 mg.

• Angiotensin II receptor blockers include agents like Benicar (olmesartan), Diovan (valsartan), and Cozaar (losartan).
• After dosing, blood pressure measurements revealed differences between Cialis and placebo (inactive pill) of 8 / 4 mm Hg in systolic / diastolic blood pressure.

Another study looked at the interaction between 5 mg of amlodipine (Norvasc), a calcium channel blocker, and Cialis 10 mg.

• After Cialis dosing, blood pressure measurements when lying down were reduced by 3 / 2 mm Hg for systolic / diastolic blood pressure when compared to placebo.
• However, a similarly conducted study using Cialis 20 mg did not find significant differences in blood pressure.

Small reductions in blood pressure were also seen when studies looked at enalapril, metoprolol and bendrofluazide.

The clinical significance of these blood pressure reductions can vary between people based on many factors. Ask your doctor if it safe for you to take your blood pressure or heart medicine with Cialis.

Does Cialis lower blood pressure if used alone?

Low blood pressure is not listed as a common side effect with Cialis when used alone.

When used alone, Cialis can dilate blood vessels which may cause small, temporary decreases in blood pressure, but in general this should not be a problem for most healthy people. Modest decreases of up to a 7 mm reduction in systolic and 5 mm in diastolic lasting up to 12 hours may occur.

• Tell your doctor if you have low blood pressure or high blood pressure that is not controlled before you start treatment with Cialis.
• Also tell them about any heart problems you might have, such as angina (chest pain), heart failure, irregular heartbeats, pulmonary (lung) hypertension, or a previous heart attack.

Tell your healthcare provider and pharmacist about all the medications you take. Use with other medicines may cause dangerous drops in blood pressure.

Does Cialis raise blood pressure?

High blood pressure (hypertension) has been noted as a possible, but infrequent, side effect in a 24-week long study. It is not a common side effect with Cialis and was not seen in all studies.

In general, hypertension is considered a blood pressure reading of 130 / 80 millimeters of mercury (mm Hg) or higher.

In the study, participants received either Cialis 2.5 mg, Cialis 5 mg or a placebo (inactive treatment), given once daily for erectile dysfunction (ED).

Hypertension (high blood pressure) was reported in:

• 3% of people taking the 5 mg dose
• 1% of people taking the 2.5 mg dose
• 0% of people taking a placebo

Before you start treatment with Cialis, tell your doctor if you have high blood pressure that is not controlled. Cialis is not recommended for use if you have uncontrolled blood pressure, a recent heart attack or stroke, chest pain (angina), heart failure, irregular heart beats, severe liver disease or retinal eye problems (for example: macular degeneration or diabetic retinopathy).

What side effects should I expect to see with Cialis?

The most common side effects with Cialis, which are usually temporary, include:

• Headache
• Indigestion
• Back pain
• Muscle pain
• Stuffy or runny nose
• Flushing (facial redness)
• Pain in the arms or legs

Back pain or muscle aches, if they occur, usually occur 12 to 24 hours after a dose of Cialis and typically go away within 2 days.

Common cold symptoms, gastroenteritis (stomach infection), and upper respiratory tract infections have also been reported.

Rarely a prolonged and painful erection of the penis lasting four hours or more (call priapism) may occur. If this occurs, or you have any other side effects that concern you, seek urgent medical help or call 911 right away.

To see a more comprehensive list of side effects, visit What side effects occur with Cialis?

Call your healthcare provider if you get any side effect that bothers you or one that does not go away.

This is not all the information you need to know about Cialis (tadalafil) for safe and effective use and does not take the place of your doctor’s directions. Review the full product information and discuss this information and any questions you have with your doctor or other health care provider.

References

• Cialis (tadalafil) prescribing and patient information. Revised 11/13/2024. DailyMed. National Library of Medicine. Accessed July 28, 2025 at https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=bcd8f8ab-81a2-4891-83db-24a0b0e25895
• Khera M (author). Patient education: Sexual problems in men (Beyond the Basics). Up to Date. Accessed Sep 13, 2023 at https://www.uptodate.com/contents/sexual-problems-in-men-beyond-the-basics
• Erectile Dysfunction. Medline Plus. Accessed Sep 13, 2023 at https://medlineplus.gov/erectiledysfunction.html
• High blood pressure (hypertension). Drugs.com. Accessed July 28, 2025 at https://www.drugs.com/mcd/high-blood-pressure-hypertension
• Hypotension. Drugs.com. Accessed July 28, 2025 at https://www.drugs.com/cg/hypotension.html

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