Can I take Hydroxychloroquine and Sildenafil together?

Why this happens

Both hydroxychloroquine and sildenafil have the potential to affect the electrical activity of the heart, specifically by prolonging the 'QT interval' (the time it takes for the heart muscle to recharge between beats). When used together, this effect can be additive, potentially leading to a rare but serious heart rhythm disturbance.

What you should do

You should speak to your doctor before using these medicines together, especially if you have a history of heart disease, heart rhythm problems, or electrolyte imbalances (such as low potassium or magnesium). Seek immediate medical help if you experience sudden dizziness, lightheadedness, fainting, or a racing/pounding heart.

Important precautions

Retinal toxicity

Long-term use can cause permanent damage to the back of the eye (retina). You must have a baseline eye test when starting and annual specialist screenings after 5 years of treatment.

Nitrate medication use

Never take this medicine if you are using nitrates (such as glyceryl trinitrate or isosorbide mononitrate) for chest pain. Combining them can cause a sudden, life-threatening drop in blood pressure.

Priapism

If you experience an erection that lasts longer than 4 hours, seek immediate emergency medical attention to prevent permanent tissue damage.

Food and drink warnings

Grapefruit juice

Grapefruit juice can increase the amount of sildenafil in your bloodstream. This may increase the risk of side effects such as headaches, flushing, or low blood pressure. It is best to avoid drinking large amounts of grapefruit juice while using this medication.

Alcohol

Drinking alcohol can make it more difficult to get an erection. Additionally, both alcohol and sildenafil can lower your blood pressure; combining them may cause dizziness, lightheadedness, or fainting. It is advisable to limit alcohol intake when planning to take sildenafil.

High-fat meals

Taking sildenafil with a heavy or high-fat meal (such as a burger and chips) can delay the medicine from working. It may take longer than usual for you to feel the effects. For the fastest results, 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.