Aug. 10, 2022 – Merck & Co.’s Januvia and Janumet, which are popular diabetes drugs, could be contaminated with a substance that could cause cancer, the FDA said in an announcement on Tuesday.

An impurity called nitrosamine was found in some samples of the drugs, which are known by the chemical name sitagliptin. The FDA is allowing Merck to continue to sell sitagliptin drugs with higher-than-allowed levels of nitrosamine to avoid shortages.

“To avoid a shortage and help ensure patients have access to an adequate supply of the medicine, FDA will not object to the temporary distribution of sitagliptin,” according to the statement.

Sitagliptin is a prescription drug used to control high blood sugar in patients with type 2 diabetes mellitus. It could be dangerous for patients to stop taking their medication without first talking to their doctor, the FDA said. The FDA also recommends that prescribers continue to use sitagliptin to prevent a gap in patient treatment.

Merck confirmed in an email to Bloomberg News that it “recently detected a nitrosamine identified as NTTP in some batches of our sitagliptin-containing medicines.”

The company is working with health authorities around the world and has put more quality controls in place to make sure the drugs meet FDA limits, Bloomberg reported.

Merck found NTTP (also called Nitroso-STG-19) in three drugs with sitagliptin: Januvia, Janumet, and Steglujan. Nitrosamine levels in a related extended-release therapy, Janumet XR, were too low to be measured, the company said.

Sitagliptin is one of a string of medications found to be contaminated with nitrosamines since 2018, Bloomberg reported. Metformin, another popular diabetes drug, has been affected previously, as well as some blood pressure pills and Chantix, a drug to help smokers quit.

Four years ago, pharmaceutical companies discovered that some blood pressure pills contained N-Nitrosodimethylamine, or NDMA, which can increase the risk of cancer if you’re exposed to it for a long time. The discovery sparked a years-long examination of common medicines that uncovered several instances of contamination, Bloomberg reported.

“Although there are no data available to directly evaluate the carcinogenic [cancer-causing] potential of NTTP, FDA used information available on closely related nitrosamine compounds to calculate lifetime exposure limits for NTTP,” according to the FDA statement.

Nitrosamines are common in water and foods, including cured and grilled meats, dairy products, and vegetables, the FDA said. Exposure to the impurities above acceptable levels over long periods of time can increase the risk of cancer.

The FDA allows 37 nanograms per day of nitrosamine in a medication, although it is allowing an interim limit of 246.7 nanograms per day in sitagliptin drugs to prevent shortages. The FDA said its calculations showed the higher limit “presents minimal additional cancer risk.”

“We remain confident in the safety, efficacy and quality of our sitagliptin-containing medicines,” Merck told Bloomberg. “No significant impact on supply of these medicines for patients is anticipated.”

Show Sources

FDA: “FDA works to avoid shortage of sitagliptin following detection of nitrosamine impurity.”

Bloomberg News: “Popular Diabetes Drug Found to Contain Potential Carcinogen.”

© 2022 WebMD, LLC. All rights reserved. View privacy policy and trust info