Can I take Allopurinol and Mirtazapine together?

Why this happens

Allopurinol and mirtazapine are processed by different pathways in the body. Allopurinol works by blocking an enzyme called xanthine oxidase to lower uric acid levels, while mirtazapine affects chemical messengers in the brain. They do not interfere with each other's absorption, metabolism, or excretion.

What you should do

You can take both medications as prescribed by your doctor. However, as with any combination of medicines, you should monitor for any new or unusual side effects and inform your healthcare provider if you feel unwell.

Important precautions

Depression and mental health disorders

Mirtazapine can cause an increase in suicidal thoughts or self-harm, particularly when first starting treatment or changing doses. Monitor your mood closely and seek immediate medical help if you notice any distressing changes.

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.

Agranulocytosis (low white blood cells)

Contact your doctor immediately if you develop signs of infection, such as a high temperature, sore throat, or mouth ulcers. Mirtazapine can rarely cause a serious drop in white blood cells.

Gout attacks

You may experience more frequent gout attacks when you first start allopurinol. Do not stop taking it if this happens; your doctor may prescribe an additional painkiller to help during the first few months.

Food and drink warnings

Alcohol

Alcohol can increase the sedative effects of mirtazapine, making you feel much sleepier and less alert. It is best to avoid drinking alcohol while taking this medicine, especially when you first start treatment or if your dose is increased.

It is best to avoid or strictly limit alcohol while taking allopurinol. Alcohol increases the level of uric acid in your blood, which can make your gout worse or trigger an attack, making the medicine less effective. Additionally, both alcohol and allopurinol can affect your liver; combining them increases the risk of liver strain.

Caffeine

High intake of caffeine may interfere with how allopurinol works to lower uric acid levels. While moderate consumption is usually fine, try to keep your caffeine intake consistent.

Water / Fluids

It is important to 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 the medicine works correctly to flush uric acid from your system.

Purine-rich foods (e.g., red meat, seafood)

While not a direct drug interaction, allopurinol is used to treat gout. Eating foods high in purines can increase uric acid levels and trigger attacks, potentially counteracting the benefits of the medication.

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.