Itraconazole

Key facts

• Itraconazole is an azole antifungal, taken as a capsule, tablet or liquid to treat fungal infections that need more than a topical cream.
• Courses often run for weeks to months depending on the infection; the liquid is best absorbed on an empty stomach, while capsules need food or an acidic drink.
• Itraconazole must not be used by anyone with heart failure or a history of it. It can reduce the heart's pumping strength and has caused new or worsening heart failure, including fatal cases.
• Seek urgent care for yellowing of the skin or eyes, swelling of the ankles or legs, or new breathlessness.

What itraconazole treats

Itraconazole treats fungal nail infections, ringworm and other skin infections that have not responded to topical treatment, and more serious infections such as aspergillosis, blastomycosis, histoplasmosis and certain yeast infections affecting internal organs. It is prescribed when a topical antifungal cannot reach or clear the infection.

How itraconazole works

Fungal cells need a substance called ergosterol to build a stable outer membrane. Itraconazole blocks the fungal enzyme that makes ergosterol, so the membrane becomes leaky and the fungal cell dies or stops growing.

Before you take it

• Do not take itraconazole if you have current or past heart failure, or if you take certain medicines that interact seriously with it, including some statins, some heart-rhythm drugs, and some migraine or sedative medicines; your pharmacist can check your full medicine list.
• Itraconazole is broken down by the same liver enzyme (CYP3A4) that clears many other drugs, so it can raise or lower their levels significantly. Always give your prescriber a complete medicine and supplement list.
• Tell your prescriber about existing liver disease; liver function is usually checked before and during longer courses.
• Avoid it in pregnancy unless the infection is life-threatening, and use effective contraception during treatment and for a period afterward.

Side effects

Common effects include nausea, headache, diarrhoea, rash and taste changes.

Stop and seek urgent medical care for any of these:

• Yellowing of the skin or eyes, dark urine, or persistent nausea and stomach pain.
• Swelling of the ankles or feet, sudden weight gain, or new shortness of breath.
• Numbness, tingling, or muscle weakness.
• A severe skin reaction or facial swelling.

Safety essentials

• Never start itraconazole if you have heart failure, and tell your prescriber immediately if you develop swelling, breathlessness or unusual fatigue during treatment, since these can signal a weakening heart.
• Liver function tests are usually checked before treatment and periodically during longer courses; stop the medicine and seek advice at any sign of liver trouble.
• Check every new medicine, including over-the-counter and herbal products, against interactions before starting, since itraconazole changes the levels of many other drugs.

This page is educational and does not replace advice from a doctor or pharmacist who knows your health history.