FDA increases nitrosamine limit for Merck diabetes drug

Aug. 10, 2022

The U.S. FDA announced this week that certain samples of Merck´s diabetes drug, Januvia, had traces of potential cancer-agent, Nitroso-STG-19 — but the agency will allow the drugmaker to keep distributing it for now.

In the statement, the FDA said that in order to prevent a shortage and keep the drug available for patients, it will temporarily up the acceptable intake limit of NTTPs in drugs to 246.7 ng, from 37 ng per day. 

In a statement to Bloomberg, Merck confirmed it found NTTP in three drugs that contain sitagliptin: Januvia, Janumet and Stegluja.

NTTP is a nitrosamine — a class of compounds of which some have been classified as possible carcinogens. While there is no data that directly evaluates the carcinogenic potential of NTTP, “FDA used information available on closely related nitrosamine compounds to calculate lifetime exposure limits for NTTP.”

Nitrosamines are everywhere, and we become exposed to them often. They can be found in water or food, and cancer risk only follows long-term exposure. This contaminant has been responsible for many drug recalls, including valsartan metformin diabetes drugs. Earlier this year, Pfizer recalled five lots of Accupril tablets, a blood pressure medication, after finding concerning levels of nitrosamine in samples.