Dosing Errors with Antifungal Agent Prompt FDA to Issue Warning

Dosing errors with antifungal agent prompt FDA to issue warning
Dosing errors with antifungal agent prompt FDA to issue warning

The Food and Drug Administration (FDA) is cautioning that dosing errors for Noxafil (posaconazole) delayed-release tablets and oral suspension have resulted due to differences in dosing regimens between the two formulations. 

As a result, the FDA has approved outer carton changes to indicate that the two oral formulations cannot be directly substituted for each other but require a dose change.  Also, the prescribing information and patient information in the drug label has been revised to alert patients and healthcare professionals that the two formulations cannot be substituted for each other. 

Noxafil oral suspension was approved in 2006, and the delayed-release tablets in 2013. The FDA received 11 reports of the wrong formulations being prescribed and/or dispensed since November 2013. One case resulted in hospitalization and one case led to death. These incidences were a result of healthcare professionals who did not know that the two oral formulations could not be substitute for one another without dose adjustment due to differences in the body's absorption and metabolism.  The delayed-release tablets have a higher bioavailability than the oral suspension so the dosing and frequency depend on the specific formulation and indication. 

RELATED: FDA Warns of Possible Dosing Error for Combo Antibiotic

The FDA recommends prescribers to specify the dosage form, strength, and frequency on all Noxafil prescriptions. Pharmacists should clarify with prescribers when the dosage form, strength, or frequency is not specified. In addition, patients should discuss with their healthcare professionals prior to switching from one oral formulation to another. Incorrect dosage and administration can result in either subtherapeutic levels and potential for treatment failures, or higher levels and potential for adverse reactions. 

Noxafil, an azole antifungal, is indicated for prophylaxis against invasive Aspergillus and Candida infections, in patients at high risk due to being severely immunocompromised, such as hematopoietic stem cell transplant recipients with Graft vs. Host Disease (GVHD) or those with hematologic malignancies with prolonged neutropenia due to chemotherapy.

Noxafil is available as 100mg strength delayed-release tablets, 40mg/mL strength cherry-flavored oral suspension, and 18mg/mL strength vials for IV infusion.

For more information visit FDA.gov.

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