SINGAPORE - A batch of potentially faulty EpiPens - which are used to treat severe allergic reactions - was distributed in Singapore but has since been recalled, said the Health Sciences Authority (HSA) on Tuesday (Sept 12).

The issue came under the spotlight last week, when pharmaceutical giant Pfizer was accused of failing to investigate hundreds of complaints about defective EpiPens, including cases where patients had died.

The United States Food and Drug Administration sent a warning letter to Meridian Medical Technologies, a division under Pfizer. According to the agency, Pfizer also did not initially remove potentially defective products from the market.

In response to queries from The Straits Times, the HSA said that a batch of the affected EpiPens had been distributed in Singapore.

However, they were recalled by the local distributor, Apex Pharma Marketing, in early April.

Some people overseas had complained that the epinephrine had leaked out of the device, meaning that there was no drug left when patients needed it. In other cases, the injectors did not work properly.

The HSA said it had not received any local reports of EpiPens failing to work. It added that the manufacturer has since taken measures to correct the root problem.

"HSA will continue to monitor the situation and the effectiveness of the actions taken," a spokesman said.