The product in question, branded as Fortodol or Leppin Miradin, drew the attention of medical agencies after 11 liver-related adverse event reports in Sweden and a further five in Norway, including the deaths.
Nimesulide is not authorised as a medicine in the UK.
In response, the FSA said in a statement on Friday: “There have been no reports of liver failure or illness linked with these products in the UK. As a precautionary measure, however, these products have been voluntarily withdrawn from sale by the two main importers and recall notices will be placed in the shops selling these supplements.”
Fortodol and Miradin are usually sold in the UK via the internet as food supplements, often accompanied by unsubstantiated claims to relieve arthritis, muscle pains and headaches.
The products are made by a Californian company called Donsbach, which typically exports the products to Sweden before they are shipped throughout Europe.
One of the Swedish cases involved a fatal liver failure which is under investigation by the Swedish Medical Products Agency. The Norwegian Medical Products Agency is conducting investigations of its own.
The FSA warning has been backed by the UK Medicines and Healthcare Products Regulatory Agency (MHRA), which, as its name suggests, governs medicines in the UK.
Nimesulide is an anti-inflammatory drug known to cause liver problems.
“Consumption of products that may contain undeclared and uncontrolled amounts of nimesulide represents a significant risk,” the MHRA said.
A similar scare in Hungary was given the all-clear by the regulator there after investigations revealed a lack of nimesulide at hazardous levels.