Confusion about the strength of the antibacterial drug Zerbaxa could potentially lead to dosage errors, the Food and Drug Administration cautioned in a May 20 announcement.
The label for Zerbaxa was approved with a strength that reflects each individual active ingredient, although the product is dosed based on the sum of these ingredients, which has led to at least seven cases of medication error, the FDA said.
“In some cases, this led to administration of 50% more drug than was prescribed,” the agency said in its statement.
To prevent future confusion, the FDA has revised the labeling to show the sum of the two active ingredients, ceftolozane and tazobactam. The strength will now be listed as 1.5 g, equivalent to 1 g of ceftolozane and 0.5 g tazobactam. This labeling is consistent with other beta-lactam/beta-lactamase medications that list drug strength as the sum of the two active ingredients, the FDA said.
Zerbaxa is approved to treat complicated urinary tract infections and intra-abdominal infections in combination with metronidazole.
No adverse events were reported in the seven cases that were evaluated. Patients and providers can report serious side effects, adverse events, and medication dosage errors to the FDA’s MedWatch program.