Can I take Sildenafil and Metformin together?

Why this happens

These drugs work in different ways and are processed by different systems in the body. Metformin helps control blood sugar levels, while sildenafil works on blood vessels to help with erectile dysfunction. They do not interfere with how the other is absorbed, used, or removed from the body.

What you should do

You can safely take these two medications together. However, because diabetes can affect your heart health and blood pressure, you should always ensure your doctor knows you are using sildenafil, as it can occasionally cause a slight drop in blood pressure.

Important precautions

Severe kidney or liver problems

You must not take metformin if you have severe kidney or liver failure, as this significantly increases the risk of lactic acidosis, a rare but life-threatening build-up of acid in the blood.

Use of nitrate medicines (e.g., glyceryl trinitrate, isosorbide mononitrate)

Never take sildenafil if you are using nitrates for chest pain or heart problems. Combining them can cause a sudden, dangerous, and potentially fatal drop in blood pressure.

Food and drink warnings

Alcohol

Drinking alcohol while taking metformin can increase the risk of a rare but serious condition called lactic acidosis. It can also cause your blood sugar levels to drop too low (hypoglycaemia). It is best to avoid excessive drinking and never drink on an empty stomach.

Grapefruit juice

Grapefruit juice can increase the amount of sildenafil in your blood, which makes side effects like headaches, flushing, or low blood pressure more likely. It is best to avoid drinking large amounts of grapefruit juice.

High-fat meals

Eating a heavy or high-fat meal (like a burger and chips) at the same time as taking sildenafil can slow down how quickly the medicine works. For the fastest effect, it is better to take it on an empty stomach or with a light meal.

Using other medicines

Taking 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.