The New Jersey-based companies market Zetia and Vytorin jointly and split the profits. Shares of both companies fell Tuesday.
The ads tell viewers that about the genetic and dietary causes of high cholesterol - "food and family" - and show "family members" interspersed with food.
Ads have also been pulled for Zetia, said Skip Irvine, a spokesman for Merck/Schering-Plough Pharmaceuticals.
"We've made the decision to voluntarily and temporarily suspend direct-to-consumer broadcast advertising in light of mischaracterization and misinterpretation of the enhanced trial results," he said, declining to elaborate or comment on the data.
However, he said print ads will continue.
The study of 720 patients was meant to show how well Vytorin reduced plaque buildup in neck arteries in people whose genes gave them stratospheric cholesterol.
Instead, it showed $100-a-month Vytorin was no more effective and perhaps a bit worse than Zocor alone, which is sold as a generic for a third as much.
In the quarter ended Sept. 30, sales of Zetia and Vytorin hit $1.3 billion, up 26 percent from the year-ago period.
Whitehouse Station, N.J.-based Merck and Kenilworth, N.J.-based Schering-Plough released only limited data from the study, which ended in April 2006.
They blamed the delay in releasing the data on the complex analysis, but doctor critics have accused the companies of first trying to change how the results were analyzed, then foot-dragging because the two drugs bring in several billion dollars a year.
Merck and Schering-Plough took the rare step of releasing partial results in a press release rather than issuing full data in a scientific journal or medical conference. The press statement was released after a congressional committee began probing the delay and what it termed "the use of misleading statements in direct-to-consumer advertisements."
The American College of Cardiology quickly put out a statement saying patients should not panic and that further research is needed to determine the best cholesterol-cutting strategy.
Shares of Merck fell $1.97, or 3.69 percent, to $51.35 on Tuesday. Shares of Schering-Plough fell 92 cents, or 4.32 percent, to $20.36.
