U.S. health officials should halt sales of estrogen and testosterone combinations made by Solvay SA and Breckenridge Pharmaceutical to treat hot flashes, a women’s health group said on Tuesday.

The National Women’s Health Network, in a petition to the Food and Drug Administration, said sales of Solvay’s Estratest and Breckenridge’s Syntest should stop because they have never been proven safe and effective for relieving hot flashes associated with menopause.

Estratest has been available in the United States since 1964 but was never approved by the FDA, while Syntest has been sold since 1997, the group said.

In 2003, the FDA itself questioned the effectiveness of estrogen/testosterone combinations and said it was launching a formal inquiry into the products.

The women’s group said the FDA should tell the companies to stop selling the treatments until they provide evidence showing their safety and effectiveness.

“Despite a lack of efficacy for the labeled (use), Solvay and Breckenridge continue to circumvent the FDA regulatory process and market these products,” the petition said.

Use of either hormone alone is known to carry risks, the petition said. Estrogen may contribute to strokes, heart attacks, breast cancer and other problems. Testosterone’s risks include liver damage and fluid retention that can lead to high blood pressure or worsen heart failure.

Estratest sales totaled $119 million in North America in 2004, the women’s group said.

FDA spokeswoman Susan Cruzan said Solvay had asked for a hearing on Estratest and the agency was reviewing that request. A Solvay spokesman had no immediate comment.

Breckenridge President Larry Runsdorf said the company would study the petition and draft a response. “There have been studies that ... seem to show the product is effective,” he said.