Itraconazole Toxicity and Cardiac Health Problems

Itraconazole is an antifungal drug used widely to treat fungal infections and is active against Aspergillus, Candida and Cryptococcus. It is effective and now much cheaper as it has passed out of the period of time granted to its inventor to exclusively sell it - there are now several competing manufacturers. It seems to be an increasingly useful and used drug now it has become more accessible which is a good thing in the main but this makes it increasingly important that this drug is properly understood and its very severe potential side effects appreciated and guarded against.

These are the warnings published by the World Health Organisation

Risk of congestive heart failure

The agency says that while the available evidence suggests that the risk of heart failure with short courses of itraconazole is low in healthy, young patients, prescribers should exercise caution when prescribing the drug to at-risk patients. Amendments to the product information of all itraconazole formulations have been made to reflect this information.

Risk to pregnant women

By April 2000 the UMC had received 43 case reports from 5 countries regarding the use of itraconazole by pregnant women. 25 of these pregnancies ended in embryonic or foetal death. The remaining 19 reports described a variety of congenital malformation or neonatal disorders. In the 38 reports in which the route of administration was specified the drug was taken orally. The data suggested that:

1. inspite of the approved recommendations and warnings itraconazole is being taken by pregnant women for minor indications,
2. reported human experience seems to lend support to the experimental evidence that itraconazole is teratogenic,
3. there is a predominance of abortion, and
4. more firm warnings may be needed in the product information.Although not apparent from the UMC reports, a further question of interest was if itraconazole might decrease the reliability of oral contraceptives and so lead to unintended exposure in pregnancy.

Care thus needs to be taken about which patients are prescribed itraconazole, adequate monitoring needs to be put in place if needed and sufficient advice given with the drug to ensure the patient is aware of the risks involved and the signs & symptoms to look out for.