Diabetologists have started getting calls from patients worried over the alert from the United States Food and Drug Administration on Metformin (ER – extended release) after it found unacceptable levels of nitrosamine impurities in the drug.

Metformin is often given as the first line of treatment for patients with Type II diabetes, and is largely considered to be safe. But nitrosamine impurities, N-Nitrosodimethylamine (NDMA) are a concern because of the possible cancer risk to people if they were exposed to it at above-acceptable levels and over long periods of time.

The diabetes drug had been on the USFDA’s radar for sometime now, even as the regulator investigated and acted on similar contaminants in heart-burn drug Ranitidine and blood pressure and heart failure drug Valsartan. In its latest alert, the USFDA has asked five companies making Metformin ER to undertake a voluntary recall in the US, the agency said, without giving names of the companies.

Diabetologist Dr V Mohan told BusinessLine that patients have been calling him, on whether to continue with the drug. “More data is required on the issue before a call can be taken on it”, Dr Mohan told Business Line. From reports presently available, it seems to be a manufacturing problem rather than a problem with the drug molecule, he said.

“If patients taking Metformin ER are uncomfortable with taking the drug in the wake of recent reports, they should talk to their doctors to possibly shift to other versions of the drug,” he advised.

Metformin has been used for over 50 years, he said. And it was given in conditions like PCOS and gestational diabetes (during pregnancy), “which is the highest form of risk, as it involves mother and child,” he said, adding that it would not have been given if it were not safe. The drug has also been investigated for use in tuberculosis; for anti-ageing properties and ironically for its anti-cancer properties as well, he said.

Another diabetes expert said that a large part of the Metformin export to the US was possibly from India. Alluding to whispers in pharma industry corridors, he said, the bad news on Metformin may be paving the way from a new drug coming in its place. Greater clarity was required on whether the contaminant was a manufacturing issue, a quality problem or an inherent worry involving the drug, the doctor said.

According to data from pharma-related market intelligence firm Aiocd-AWACS, Metformin is an estimated Rs 400 crore segment, while as a combination drug with other diabetes molecules, the segment is pegged at over Rs 7,700 crore. A host of drugmakers produce the product in India including USV, Glenmark, Lupin, Dr Reddy’s, Sun Pharma, Sanofi and Granules, an industry watcher said, adding that the Indian drug regulator too needs to put out an advisory on the drug.