Karen Bleier, Getty Images
Dr. Robert Jarvik

WASHINGTON — When "diet and exercise isn't enough," Pfizer still wants consumers to ask their doctor about Lipitor — just not Dr. Robert Jarvik.

On Monday, Pfizer took the former Utahn off the mound as pitchman for the world's best-selling medication, after his credentials — in medicine and in his own exercise regimen — came under fire.

In the ads, Jarvik touts the benefits of Pfizer's cholesterol-lowering drug.

But members of the House Energy and Commerce Committee has raised questions about the ads, saying they could be misleading to consumers because Jarvik appeared to be giving medical advice, even though he is not licensed to practice medicine. While Jarvik holds a medical degree, he did not complete the certification requirements to practice medicine.

Also, in a letter to Pfizer in August 2006, three former colleagues of Jarvik's at the University of Utah complained the ads erroneously identified Jarvik as "inventor of the artificial heart." That distinction, they said, should go to Jarvik's mentor, Dr. Willem J. Kolff, and his associate, Dr. Tetsuzo Akutsu.

Pfizer subsequently changed its ads to identify Jarvik as the inventor of the "Jarvik artificial heart," but Jarvik's former colleagues, members of a large team that worked on the heart, were not entirely satisfied, according to Dr. Donald B. Olsen, a veterinarian who worked on the heart and is president of the Utah Artificial Heart Institute. Olsen said he was recently contacted by the House committee.

A long-simmering dispute over assigning credit for the artificial heart boiled over again during a conference last December at the University of Utah. Dr. Jarvik did not attend the conference, which marked the 25th anniversary of the heart's experimental use to extend the life of Dr. Barney Clark, a Seattle dentist.

During the meeting, another former Utah colleague of Jarvik's, Dr. Clifford S. Kwan-Gett, stated that the Jarvik series of hearts were simply different versions of prototypes that Kwan-Gett had made more than a year earlier.

Jarvik's company, Jarvik Heart, subsequently posted a history of the artificial heart's development on its Web site, giving his own account of the heart's development. That posting said Jarvik's design overcame two problems of the heart developed by Kwan-Gett.

The House Energy and Commerce Committee chaired by Rep. John D. Dingell, D-Mich., disclosed that Pfizer agreed to pay Jarvik at least $1.35 million under a two-year contract that expired next month.

Democratic Reps. Dingell and Bart Stupak said Monday the company made the right decision to stop using Jarvik in its ads.

"When consumers see and hear a doctor endorsing a medication, they expect the doctor is a credible individual with requisite knowledge of the drug," Stupak said.

In January, the lawmakers asked Pfizer to hand over all records of its contract with Jarvik as part of a larger investigation into celebrity endorsements of prescription medicines.

While endorsing Pfizer's decision, the committee showed no sign of shutting down its investigation. Stupak said the committee planned to meet with Jarvik and collect all of the documents it had requested.

Jarvik, who has recently declined to discuss the Lipitor campaign, could not be reached for comment Monday.

Lipitor ad scrutiny intensified earlier this month when the New York Times reported that Pfizer used a stunt double in an ad in which Jarvik appeared to be rowing. The company replaced that ad with one showing Jarvik jogging with his son.

In a statement Monday, Pfizer president of operations Ian Read said "the way in which we presented Dr. Jarvik in these ads has, unfortunately, led to misimpressions and distractions."

Read said the company will provide "greater clarity in our advertising regarding the presentation of spokespeople."