The US Food and Drug Administration (FDA) has announced that it is conducting a close examination of the weight loss drug orlistat, following reports of liver injury in patients.

Between 1999 and 2008, the FDA received 32 reports of serious liver injury in patients taking orlistat, which is marketed by Roche Holding AG as the prescription drug Xenical and as an over-the-counter medication Alli by GlaxoSmithKline.

Of the reported cases, 30 occurred outside of the US, 27 resulted in hospitalisation and six resulted in liver failure. Other common side effects included yellowing of the skin or whites of the eyes (jaundice), weakness and stomach pain.

The FDA is now reviewing additional data submitted by orlistat manufacturers on suspected cases of liver injury, and the issue is being followed up by the FDA’s Centre for Drug Evaluation and Research Drug Safety Oversight Board.

FDA Research Drug Safety Oversight Board executive director Steven Osborne said that the issues are complex, but the FDA has benefited from the input of the Board, including comments from representatives from three FDA Centers and several other Agencies in the Department of Health and Human Services.

The FDA has also made it clear, however, that as yet no definite association between liver injury and orlistat has been established and patients should continue to take the medication as prescribed.