Skip to main content

Can I take Desmopressin and Ketoconazole together?

Drug interaction guide

Taking these two medicines together can significantly increase the amount of desmopressin in your blood. This can lead to your body holding onto too much water, which can cause a dangerous drop in your blood salt levels (hyponatraemia). Symptoms to watch for include severe headache, nausea, vomiting, confusion, or feeling very drowsy.

Continue reading below

Why this happens

Ketoconazole blocks a specific enzyme in your liver and gut (called CYP3A4) that is responsible for breaking down many medicines. When this enzyme is blocked, desmopressin stays in your system much longer and reaches higher levels than intended.

You should speak to your doctor before taking these medicines together. They may want to monitor your blood salt levels or adjust your dose. If you experience a sudden headache, confusion, or feel unusually sick while taking both, seek medical advice immediately.

Continue reading below

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.

Article history

The information on this page is written and peer reviewed by qualified clinicians.

  • 14 Mar 2026 | Originally published
flu eligibility checker

Ask, share, connect.

Browse discussions, ask questions, and share experiences across hundreds of health topics.

symptom checker

Feeling unwell?

Assess your symptoms online for free

Sign up to the Patient newsletter

Your weekly dose of clear, trustworthy health advice - written to help you feel informed, confident and in control.

Please enter a valid email address

By subscribing you accept our Privacy Policy. You can unsubscribe at any time. We never sell your data.