A new drug may reduce or prevent nausea and vomiting from cancer chemotherapy with fewer side effects than older treatments, the manufacturer said.

Administered intravenously, Zofran is the first of a new class of agents to be approved in the United States for the prevention of chemotherapy-induced nausea and vomiting, officials of Glaxo Pharmaceuticals said Tuesday. The company is based in Research Triangle Park, N.C.The agents block serotonin, a natural chemical that constricts blood vessels, contracts smooth muscle tissue like the stomach and is important in mental activity.

"With Zofran, we can minimize the side effects of chemotherapy and may improve the quality of life for cancer patients," said Dr. Kelly Pendergrass, chief of medical oncology at Research Medical Center in Kansas City, Mo.

Pendergrass said the drug, approved last month by the Food and Drug Administration, can control nausea and vomiting even in patients receiving high-dose cisplatin. Cisplatin is a valuable treatment for several types of cancer, but is toxic and often causes severe vomiting that may force doctors to curtail chemotherapy.