ADELPHI, Md.  A federal advisory panel voted narrowly on Tuesday to recommend a ban on Percocet and Vicodin, two of the most popular prescription painkillers in the world, because of their effects on the liver.

The two drugs combine a narcotic with acetaminophen, the ingredient found in popular over-the-counter products like Tylenol and Excedrin. High doses of acetaminophen are a leading cause of liver damage, and the panel noted that patients who take Percocet and Vicodin for long periods often need higher and higher doses to achieve the same effect.

Acetaminophen is combined with different narcotics in at least seven other prescription drugs, and all of these combination pills will be banned if the Food and Drug Administration heeds the advice of its experts. Vicodin and its generic equivalents alone are prescribed more than 100 million times a year in the United States.

Laureen Cassidy, a spokeswoman for Abbott Laboratories, which makes Vicodin, said, “The F.D.A. will make a final determination and Abbott will follow the agency’s guidance.”