FDA warns about dosing errors with antifungal

January 7, 2016

After a death and a hospitalized patient, FDA is cautioning that differences in dosing regimens between the 2 oral formulations of Merck’s antifungal drug Noxafil (posaconazole) have resulted in dosing errors.

After a death and a hospitalized patient, FDA is cautioning that differences in dosing regimens between the 2 oral formulations of Merck’s antifungal drug Noxafil (posaconazole) have resulted in dosing errors.

Related: FDA's accelerated drug reviews need fixing

“To help prevent additional medication errors, the drug labels were revised to indicate that the two oral formulations cannot be directly substituted for each other, but require a change in dose. Direct mg. for mg. substitution of the two formulations can result in drug levels that are lower or higher than needed to effectively treat certain fungal infections,” FDA said in a statement.

Since the approval of Noxafil delayed-release tablets in November 2013, FDA has received 11 reports of the wrong oral formulations being prescribed and/or dispensed to patients. One case resulted in death, and an additional case resulted in hospitalization.

“According to the reports, 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,” FDA said.

Related: Why manufacturer is recalling hospital blood pressure drug

Noxafil is approved in 2 oral formulations: an oral suspension and a delayed-release tablet, to help prevent certain invasive fungal infections caused by Aspergillus and Candida. Noxafil is used in patients who have an increased chance of getting these infections due to weakened immune systems. Noxafil oral suspension is also used to treat a fungal infection called thrush caused by Candida in the mouth or throat area. 

After the incidents, FDA said that prescribers should specify the dosage form, strength, and frequency on all prescriptions they write for Noxafil.  Pharmacists, meanwhile, should request clarification from prescribers when the dosage form, strength or frequency is not specified.

Baxter recall

In other drug safety news, Baxter International announced a voluntarily recall of 2 lots of intravenous (IV) solutions, Sodium Chloride and Dextrose, to the hospital/end user level because of the potential presence of particulate matter. “The particulate matter in each case was determined to be an insect and was identified as a result of a customer complaint,” according to an FDA statement.

The lots being recalled were distributed to customers and distributors in the United States between June 6, 2015 and December 16, 2015. “Injecting a product containing particulate matter, in the absence of in-line filtration, may result in blockage of blood vessels, which can result in stroke, heart attack or damage to other organs such as the kidney or liver. There is also the possibility of allergic reactions, local irritation and inflammation in tissues and organs,” the statement said.

Read next: Serious risks associated with SGLT2 inhibitors