FDA warns of dosing errors involving Noxafil oral tablets

The Food and Drug Administration (FDA) is warning health-care professionals and patients that dosing errors have occurred when switching between two different oral formulations of Noxafil.

Noxafil is an antifungal used to prevent certain fungal infections caused by Aspergillus and Candida in individuals with weakened immune systems. Its oral suspension tablets were approved in 2006 followed by delayed-release tablets in 2013. Since the approval of the latter formulation, the FDA has received 11 reports of incorrect oral formulations being prescribed or dispensed with one case resulting in hospitalization and another in death.

"These outcomes were a result of health-care professionals not knowing that the two oral formulations cannot be substituted for each other without adjusting the dose due to differences in how the medicine is absorbed and handled by the body," the FDA said.

In order to prevent future dosing errors, the outer cartons and drug labels for Noxafil has been changed to alert users that the two oral tablets aren't interchangeable.

The FDA recommends that prescribers specify the dosage form, strength and frequency of all Noxafil prescriptions and pharmacists should seek clarification from prescribers when these factors aren't specified. Additionally, patients are encouraged to speak to their health-care professional before switching oral formulations as direct dosage substitution could lead to drug levels that are lower or higher than required to effectively and safely treat the infections.