According to the US FDA on Tuesday, a probable carcinogen was found in some samples of sitagliptin, a component of Merck & Co. Inc’s (NYSE: MRK) diabetic medications (Januvia and Janumet).

Merck informed authorities when it discovered the contaminants

In order to ensure that its medications will comply with the temporarily allowed limits, Merck claimed that it informed authorities when it discovered that some units of the drugs included the contaminants and added additional quality controls.

Despite finding contaminants in some batches of the drugs, the agency will allow the company to temporarily sell the drugs containing sitagliptin, including those with higher than usual levels of a contaminant called Nitroso-STG, popular as NTTP. The agency stated that it will allow the sale because the patients’ immediate medical needs outweigh potential risks. However, the agency warns patients not to stop taking sitagliptin without a physician’s advice. 

Merck stated that it remains optimistic about the safety, effectiveness, and quality of sitagliptin-containing medications,” adding that no appreciable supply disruption is anticipated.

In the second quarter, the company reported $1.23 billion in revenue for Januvia and a comparable combination drug named Janumet.

NTTP linked to human carcinogens 

According to the FDA, NTTP is a member of the nitrosamine class of substances, some of which have been identified through laboratory testing as being likely or suspected human carcinogens. When contrasted to a lifetime of contact with NTTP at the value of 37 nanograms per day, agency scientists found that the risk from exposure to NTTP at interval permitted intake level increases to 246.7 nanograms per day poses a little additional cancer risk.

Because of nitrosamines, some pharmaceutical companies have recently been forced to recall certain batches of medications like Pfizer’s Chantix, an anti-smoking aid, and stop offering others like ranitidine, a medication used to manage heartburn and frequently marketed under the name Zantac.

Water and food sources, including treated and grilled meats, dairy goods, and vegetables, frequently include nitrosamines. Long-term exposure to contaminants above permissible levels may raise cancer risk.