Can I take Allopurinol and Candesartan together?
Drug interaction guide
Originally published 25 Jan 2026
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Taking allopurinol and candesartan together may increase the risk of a rare but serious allergic reaction. It can also lead to a higher risk of your blood pressure dropping too low or your kidney function being affected.
Why this happens
Both drugs can affect how the kidneys work. When used together, they may increase the sensitivity of the immune system, making a severe skin rash or allergic reaction more likely. Additionally, they can have an additive effect on lowering blood pressure and kidney filtration.
What you should do
You can usually take these together, but you must be monitored by your doctor. Seek immediate medical help if you develop a skin rash, hives, or swelling of the face. Your doctor may want to perform regular blood tests to check your kidney function and monitor your blood pressure closely.
Important precautions
Severe skin reactions (SCARs)
Stop taking allopurinol immediately and seek urgent medical help if you develop a skin rash, peeling skin, or mouth ulcers. This can be a sign of a rare but life-threatening allergic reaction.
Pregnancy
Do not take candesartan if you are pregnant or planning to become pregnant. It can cause serious harm or death to an unborn baby, particularly if used in the second and third trimesters.
High potassium levels (Hyperkalaemia)
Avoid using potassium supplements or salt substitutes containing potassium while taking candesartan, as it can cause dangerously high levels of potassium in your blood.
Food and drink warnings
Alcohol
Alcohol can increase the levels of uric acid in your blood, which makes allopurinol less effective at preventing gout attacks. It is best to limit your intake, especially beer and spirits.
It is best to avoid or strictly limit alcohol while taking candesartan. Combining alcohol with this medicine can cause your blood pressure to drop too low, making you feel dizzy, lightheaded, or faint, especially when standing up. Alcohol also increases the risk of dehydration, which can affect your kidney function while on this medication.
Caffeine
High intake of caffeine may interfere with how allopurinol works to lower uric acid. Try to keep your intake of tea, coffee, and cola consistent.
Water/Hydration
You must drink plenty of fluids (at least 2 to 3 litres a day) while taking allopurinol. This helps to prevent the formation of kidney stones and ensures your kidneys can flush out uric acid effectively.
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.
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