Singapore’s Health Sciences Authority (HSA) is recalling these three metformin medicines as a precautionary measure

Three metformin medicines have been found to contain trace amounts of a nitrosamine impurity, N-nitrosodimethylamine (NDMA), which are above the internationally acceptable level. As a precautionary measure, the Health Sciences Authority (HSA) is recalling these three metformin medicines that are used to control high blood sugar levels in diabetic patients.

HSA said that it has tested all 46 locally marketed metformin medicines, and that only 3 out of 46 metformin medicines were found to contain NDMA above the acceptable level. The other 43 metformin medicines are not affected.

HSA assured that the risk to patients who have been taking the 3 affected metformin medicines is very low. This is because the potential risk of nitrosamines is associated with long-term use, and the 3 affected medicines have only been supplied locally for a short period of time since last year.

“For example, the added cancer risk from an additional 6-month exposure is estimated to be less than 0.00002%,” HSA said.

Patients taking the affected metformin medicines were advised by HSA not to stop treatment on their own, as the sudden stopping of medicines will raise blood sugar levels, which may pose a greater health risk than the trace amounts of NDMA in the affected medicines.

It also advised healthcare professionals to contact their patients who are taking the affected medicines to arrange for an exchange of their medicines as soon as practicable. Patients who are concerned about their current treatment can speak to their doctor or pharmacist.

HSA said that it is working with the companies supplying these medicines and international regulatory agencies to verify the causes of the contamination, and to identify the necessary measures to address the issue.