If you have high blood pressure or a heart condition, it is natural to wonder whether ED tablets are safe for you. The short answer: they lower blood pressure a little, most men on blood pressure medicines can take them, and there is one combination that is never safe. This guide explains each part.
Does Viagra lower blood pressure?
Yes, slightly and for a short time. ED tablets widen blood vessels throughout the body, not just in the penis. In healthy volunteers, sildenafil (Viagra) lowered blood pressure by an average of about 8/6 mmHg at its peak, and the label says this would normally be of little consequence for most people1. In a similar study, tadalafil (Cialis) made no significant difference to blood pressure compared with a dummy tablet2.
That small effect is not a treatment for high blood pressure. Sildenafil is also used for a different condition, pulmonary arterial hypertension (high pressure in the blood vessels of the lungs)3, which is not the same as ordinary high blood pressure.
ED can be an early warning sign
The blood vessels in the penis are narrow, so erection problems can be one of the first signs of narrowed, hardened arteries (atherosclerosis), the same process that leads to heart attacks4. Heart and urology experts now advise treating men with ED as at risk of heart disease until shown otherwise5. If you have ED and have not had your blood pressure, cholesterol and blood sugar checked recently, it is worth doing.
The absolute no: nitrates
Never take an ED tablet if you use a nitrate medicine, such as glyceryl trinitrate (GTN) spray or tablets for angina, or isosorbide mononitrate. The combination can make blood pressure fall dangerously low12. The same applies to:
- Riociguat, a medicine for lung blood pressure1
- Nicorandil, another angina medicine6
- “Poppers” (amyl nitrite and similar), used recreationally6
If you get chest pain after taking an ED tablet, call emergency services and tell them what you took and when. The labels set out how long doctors should wait before giving a nitrate in an emergency: at least 48 hours after tadalafil2 and at least 12 hours after avanafil7. For sildenafil and vardenafil, the labels say a safe gap has not been established18.
Blood pressure medicines: usually compatible
European guidelines say that taking ED tablets with blood pressure medicines may cause small extra falls in blood pressure, usually minor, and that side effects are generally no worse even in men taking several blood pressure medicines6. For example, taking sildenafil with amlodipine lowered blood pressure by about another 8/7 mmHg1.
Alpha-blockers need more care. These include doxazosin for blood pressure, and tamsulosin or alfuzosin for an enlarged prostate. Together with an ED tablet, they can sometimes lower blood pressure enough to cause dizziness or fainting. The labels advise being stable on the alpha-blocker first, then starting the ED medicine at the lowest dose12. Our guide to tamsulosin vs finasteride explains these prostate medicines.
Very high or very low blood pressure is a reason for caution. The Viagra label notes there is no trial data in people with blood pressure below 90/50 or above 170/1101, and the NHS says sildenafil may not be suitable if you have low blood pressure or uncontrolled high blood pressure3.
For more on common blood pressure medicines, see ACE inhibitors vs ARBs.
Is sex safe for your heart?
Sex is physical activity, and for people with heart disease it carries some risk of its own. The labels say ED medicines should not be used by men for whom sexual activity is inadvisable because of their heart1. To judge this, doctors often use the risk groups from the Princeton consensus, which the European guidelines reproduce6:
| Risk group | Examples | What usually happens |
|---|---|---|
| Lower risk | Can do moderate exercise without symptoms; controlled high blood pressure without symptoms; mild heart valve disease; successfully treated blocked arteries | Sexual activity is not a significant heart risk; ED treatment can usually go ahead |
| Intermediate or uncertain risk | Mild or moderate stable angina; a heart attack 2 to 8 weeks ago; moderate heart failure; a past stroke or mini-stroke; narrowed leg arteries | Further tests, such as an exercise test, before resuming sexual activity |
| Higher risk | Unstable angina; uncontrolled high blood pressure; severe heart failure; a heart attack in the last 2 weeks; dangerous heart rhythm problems | The heart condition is treated and stabilised first |
Source: European Association of Urology guidelines, based on the Princeton IV consensus65.
After a heart attack or stroke
The Viagra label says there is no controlled trial data in people who have had a heart attack, stroke or life-threatening heart rhythm problem in the last 6 months, so it should be used with caution1. The British Heart Foundation says PDE5 inhibitors can be prescribed from 6 months after a heart attack, provided your condition is stable4. Your heart team is the right place to decide when.
Heart rhythm problems
Vardenafil can affect the heart’s rhythm on an ECG (the QT interval). People born with a long QT interval, or taking certain heart rhythm medicines such as amiodarone, sotalol, quinidine or procainamide, should avoid it8. Poorly controlled atrial fibrillation and other high-risk rhythm problems put you in the higher-risk group above6.
Blood thinners
In studies, sildenafil did not increase bleeding time when taken alone or with aspirin, and had no significant interaction with warfarin1. Tadalafil did not change warfarin levels or its effect on blood clotting, and did not prolong bleeding time with aspirin2. However, the labels say these medicines have not been studied in people with bleeding disorders or active stomach ulcers12, so mention these to your prescriber.
Questions to ask your doctor
- Is my heart healthy enough for sexual activity?
- Do any of my medicines, including anything I take only now and then, contain a nitrate?
- Should I start at a lower dose because of my blood pressure or prostate medicines?
- What should I do if I get chest pain during or after sex?
For more on how these medicines compare, see our guide to ED medication side effects. Our ED medicines page lists what we supply, including Cialis 5 mg, and our heart care medicines page covers blood pressure and heart treatments.
Frequently asked questions
Can I take Viagra with blood pressure medication?
Usually yes. Most blood pressure medicines can be taken with ED tablets, with only a small extra fall in blood pressure. Alpha-blockers need a lower starting dose, and nitrates must never be combined with ED tablets.
Does Cialis lower blood pressure?
In healthy volunteers, tadalafil made no significant difference to blood pressure compared with a dummy tablet. Like other ED medicines, it can add to the effect of blood pressure medicines and alcohol.
Can I take Viagra with amlodipine?
Usually yes. In a study, taking sildenafil with amlodipine lowered blood pressure by about another 8/7 mmHg. Tell your prescriber about all your blood pressure medicines.
Can ED pills cause a heart attack?
Heart attacks have been reported in men taking ED tablets, usually during or soon after sex and mostly in men who already had heart risk factors. It is not possible to say whether the tablet, the sexual activity or the underlying heart disease was responsible. That is why a heart check matters if you have risk factors.
Why can’t you take Viagra with nitroglycerin?
Both widen blood vessels, and together they can drop blood pressure to a dangerous level. If you get chest pain after taking an ED tablet, tell the emergency team what you took and when.
Can I take Viagra with blood thinners?
Studies found no significant interaction with warfarin or aspirin. The medicines have not been studied in people with bleeding disorders or active stomach ulcers, so tell your prescriber if either applies to you.
Sources & references
- US National Library of Medicine, DailyMed. Viagra (sildenafil) prescribing information.
- US National Library of Medicine, DailyMed. Cialis (tadalafil) prescribing information.
- NHS. Sildenafil (Viagra). Page last reviewed 29 July 2026.
- British Heart Foundation. Erectile dysfunction, Viagra and your heart. Updated 29 May 2026.
- Kohler TS, Kloner RA, et al. The Princeton IV Consensus Recommendations for the Management of Erectile Dysfunction and Cardiovascular Disease. Mayo Clin Proc. 2024;99(9):1500-1517.
- European Association of Urology. EAU Guidelines on Sexual and Reproductive Health: Management of erectile dysfunction.
- US National Library of Medicine, DailyMed. Stendra (avanafil) prescribing information.
- US National Library of Medicine, DailyMed. Vardenafil tablets prescribing information.
Related reading
- Viagra not working? What to try next
- Exercising on beta-blockers
- Sildenafil medicines
- Tadalafil medicines
This content is for informational purposes only and is not medical advice. If you have a heart condition, talk to your doctor before taking any ED medicine, and never combine ED medicines with nitrates. Used as prescribed by a licensed medical professional.
Nicholas Brain is a licensed clinical pharmacist with 16 years of experience. He holds a B.Pharm and M.Pharm from Kannur University. At OnlineMeds, he reviews medicine and health content to help ensure it is accurate, evidence-based, and easy to understand.