GlaxoSmithKline is warned over contamination at an Ireland plant, and has recalled Alli from US retailers over tampering concerns.

Pharma giant GlaxoSmithKline (GSK) has been warned by the US Food and Drug Administration (FDA) to address manufacturing problems at the SmithKline Beecham chemical plant in Cork, Ireland, after FDA inspectors found evidence of contamination.

In a warning letter to the company’s chief executive, FDA officials raised concerns over contamination of active pharmaceutical ingredients with solvents and intermediates from a waste tank. The letter criticised GSK’s initial response to the issues, saying that some product batches were shipped despite others being held back, and that the equipment checks were inadequate to rule out further contamination. This is not the first time the company has been in trouble over manufacturing practices. In 2010 they agreed to pay $750 million (£452 million) to settle charges relating to the manufacture of adulterated drugs at the now closed plant at Cidra, Puerto Rico.

Meanwhile, GSK has recalled all supplies of weight loss drug Alli from retailers in the US in response to widespread reports of product tampering. Customers from seven states have reported finding fake pills that are the wrong colour, or bottles with broken seals inside the outer packaging of Alli products bought from drug stores. GSK has recalled all supplies sold in US stores while it investigates, and has urged customers to come forward if they suspect that their product has been interfered with.