Can I take Sildenafil and Bisoprolol together?
Drug interaction guide
Originally published 25 Jan 2026
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Taking sildenafil (Viagra) and bisoprolol together can cause your blood pressure to drop lower than intended. This may make you feel dizzy, light-headed, faint, or cause a headache.
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Why this happens
Both medicines work to widen or relax blood vessels, though they do so in different ways. Bisoprolol is a beta-blocker used for heart rate and blood pressure, while sildenafil relaxes the smooth muscle in blood vessel walls. When combined, their effects add together, leading to a more significant reduction in blood pressure.
What you should do
Back to contentsYou can usually take these together, but you should use caution. Start with the lowest possible dose of sildenafil. When you first start taking them together, be careful when standing up quickly from a sitting or lying position. If you feel very dizzy or faint, sit or lie down immediately and contact your doctor. Always ensure your doctor knows you are taking bisoprolol before they prescribe sildenafil.
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Important precautions
Back to contentsAsthma or COPD
Bisoprolol can cause narrowing of the airways, which may trigger a severe asthma attack or worsen breathing difficulties. It is generally avoided if you have a history of wheezing.
Nitrate medication use (e.g., GTN spray, isosorbide mononitrate)
You must never take sildenafil if you use nitrate medicines for chest pain or heart failure. Combining them causes a dangerous, potentially fatal drop in blood pressure.
Diabetes
Bisoprolol can hide the early warning signs of low blood sugar (hypoglycaemia), such as a fast heartbeat or tremors. You must monitor your blood sugar more closely.
Food and drink warnings
Back to contentsAlcohol
Alcohol can increase the blood pressure-lowering effect of these medicines. This may make you feel dizzy, lightheaded, or faint, especially when standing up. It is best to limit alcohol intake, particularly when starting treatment or changing doses.
Grapefruit juice
Grapefruit juice can increase the level of sildenafil in your blood, which may increase the risk of side effects like headaches, flushing, or low blood pressure. Avoid drinking large amounts of grapefruit juice while taking this medicine.
High-fat meals
Taking sildenafil with a heavy or high-fat meal (such as a burger and chips) can delay the medicine's absorption. This means it may take longer to start working than usual.
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Using other medicines
Back to contentsTaking multiple medicines? Our Medicines Interaction Checker helps you check whether your prescriptions, over-the-counter medicines, and supplements are safe to take together. Simply search for your medicines to see potential interactions and what to do about them.
Disclaimer
This information is for general educational purposes only and should not be relied upon as a substitute for professional medical advice. Always consult your GP, pharmacist, or another qualified healthcare professional before making decisions about your medications. Individual circumstances may vary, and only a healthcare professional who knows your medical history can provide personalised guidance.
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Article history
The information on this page is written and peer reviewed by qualified clinicians.
25 Jan 2026 | Originally published

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