The US health regulator has asked drug major Dr Reddy's Laboratories to initiate voluntary action at its Duvvada facility in Andhra Pradesh. "With regard to the audit of our Formulations Manufacturing Plant at Duvvada, Visakhapatnam, we would like to inform you that we have been notified by the United States Food and Drug Administration (USFDA), that the inspection classification of the above-referred facility is determined as Voluntary Action Initiated," Dr Reddy's Laboratories on Sunday said in a BSE filing. Shares of Dr Reddy's Laboratories on Friday closed at Rs 3,307.50 apiece, down 0.55 per cent on the BSE.