The Food and Drug Administration is warning patients about a potential mix-up between powerful prescription pain drugs and common over-the-counter medications made at a Novartis manufacturing plant. The issue stems from manufacturing problems at a Lincoln, Neb., facility which triggered a recall Sunday of 1,645 lots of Novartis’ over-the-counter drugs, including Excedrin, Bufferin, NoDoz and Gas-X. The company has received hundreds of complaints of broken and chipped pills and inconsistent bottle packaging that could cause pills to be mixed up. Consumers are advised to stop using the products and contact the company for a refund.