The craze around pricey weight-loss drugs has many people clamoring for these treatments in company-sponsored health plans.

While less than half of large employers currently cover the new generation of obesity drugs, an additional 18% say they're considering adding them amid surging interest, according to preliminary findings from 1,062 firms surveyed by Mercer, a human-resources consulting firm.

"There are just thousands and thousands of patients reaching out to us," said James Wantuck, associate chief medical officer at health-services company Accolade Inc. Employers have a tough choice, he said, because the medicines "work really well" but "they're very expensive."