FDA warns about painkiller mix-up in Excedrin, Bufferin (VIDEO)

The U.S. Food and Drug Administration has warned of a possible mix-up affecting various prescription pain medications and some of the most-common over-the-counter drugs.

According to CNN, the FDA is advising patients who use certain prescription medications produced by Endo Pharmaceuticals — including Percocet, Endocet, Opana and Zydone — to visually inspect their pills.

And consumers who have chosen bottles of Excedrin, Bufferin, NoDoz and Gas-X made at a Novartis plant are being told to discard or return the products as part of a voluntary recall by the Swiss drugmaker that started Sunday, according to the Associated Press. 

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The FDA said the problem resulted from major manufacturing problems at a Novartis facility in Lincoln, Nebraska, that shut down last month.

Because of packaging and labeling problems at the plant, "it's possible that tablets from one product may have been retained in the packaging machinery, and then may have carried over into the packaging" of another medicine, USA Today quoted Edward Cox of the FDA's Center for Drug Evaluation and Research as saying Monday.

"We are asking patients to check their medicines, to look for any tablets of a different size, shape or color from their regular medicine," Cox reportedly said. "If they find any tablets that are different, stop taking the pain medication and take the medicine to the pharmacy. We are telling patients to look carefully at all tablets in pain medication bottle."

Novartis was asking consumers to return the product by mail for a full refund. "Consumers also will be given $2 for shipping costs." More information was available on the company's website.

MSNBC cited FDA officials as saying they were not recalling the drugs because they were medically necessary and the likelihood that they contained stray pills was low.