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

Eye health and vision

Hydroxychloroquine can cause permanent damage to the retina. You must have a baseline eye test before starting and regular annual screenings if you take it long-term. Report any new blurred vision or blind spots immediately.

Heart rhythm disorders

Hydroxychloroquine can affect your heart rhythm, especially if taken with other medicines that affect the heart. Seek immediate medical help if you experience palpitations, fainting, or severe dizziness.

Nitrate medication use

Never take sildenafil 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 - sildenafil

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

It is best to avoid or strictly limit alcohol while taking these medicines. For sildenafil, alcohol can make it harder to get an erection and may increase the risk of dizzy spells or low blood pressure. For hydroxychloroquine, both the medicine and alcohol are processed by the liver; combining them may increase the strain on your liver.

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.