Author: Hon A/Prof Amanda Oakley, Dermatologist, Hamilton, New Zealand, 2004.
Itraconazole is an triazole medicine used to treat fungal infections.
Itraconazole is effective against a broad spectrum of fungi including:
Itraconazole has recently been observed to slow the growth of basal cell carcinoma, and is occasionally used for this purpose off-label.[1,2]
Itraconazole binds to the fungal p450 enzymes and stops the cells making ergosterol, the main component of the cell wall.
In New Zealand, itraconazole is available as 100 mg capsules on prescription and a 10 mg/mL liquid preparation. A generic, Itrazole, is funded under some circumstances. Sporanox™, is the registered trademark for itraconazole preparations, copyright Janssen-Cilag. Sporanox oral liquid is subsidised on Special Authority application for children with immunodeficiency and relevant infections.
The medication is better absorbed orally when it is taken with a fatty meal or acidic drink (eg, orange juice). It is bound to proteins such as albumin in the circulating blood and becomes concentrated in fat cells and within skin and nails. It takes one to three days for half of the medication to be cleared from the blood stream. The rest is eliminated in faeces and urine after conversion by the liver into inactive compounds.
Skin concentrations may be 3–10-fold higher than those in the blood. It may persist in the skin for up to 4 weeks after the drug has been discontinued and in the nails for up to a year.
Various regimes for itraconazole have been found successful; typical doses are listed below. Courses can be repeated and the medication can be continued for months if necessary.
The dose of itraconazole in children is usually 5 mg per kg body weight per day to maximum 200 mg per day, but is reserved for exceptional circumstances.
Itraconazole appears to be a relatively safe drug. Side effects, usually minor, are more likely during a prolonged course of treatment.
Itraconazole is best avoided in pregnancy. Although only excreted in tiny amounts from breast milk, it should only be taken by a breast-feeding mother if essential.
Itraconazole has important interactions with other medications.
As itraconazole needs acid for its absorption, antacids, H2 antagonists (cimetidine, famotidine, ranitidine) and omeprazole should not be taken for 2 hours after itraconazole.
Itraconazole is a P-glycoprotein inhibitor and increases the concentration of some drugs.
These drugs should not be taken by those on itraconazole:
Itraconazole may increase the risk of bleeding from anticoagulants such as warfarin or dabigatran.
The dose of these drugs should be reduced:
The dose of these drugs may need reducing if side effects arise:
The following drugs decrease the concentration of itraconazole:
Itraconazole is not thought to interact with the oral contraceptive pill.
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