Giving the anti-vomiting drug Zofran to children dehydrated by viral gastroenteritis helps them recover, but emergency room doctors may be overusing the quick-dissolving tablets, according to a study released on Wednesday.

Over 1.5 million emergency room visits a year are due to childhood gastroenteritis. Doctors encourage dehydrated children admitted to emergency rooms with a “bug” to drink an electrolyte solution. But many are vomiting, so they can’t keep it down.

One alternative is to administer fluid intravenously. Another is to give children Zofran, GlaxoSmithKline Plc.‘s brand name for ondansetron, to stop the vomiting, according to a study published in this week’s New England Journal of Medicine.

“Children who received ondansetron had fewer episodes of vomiting, greater oral intake of fluids and a shorter stay in the emergency department,” said the research team, led by Stephen Freedman of the University of Toronto.

They found that Zofran helped reduce the need for intravenous, or IV, therapy. Only 14 percent of the 107 children treated with the drug needed IV treatment to relieve their dehydration. More than twice as many who received a placebo (31 percent), needed to receive their fluids by needle.

The study also suggested Zofran is being overused, said co-author Elizabeth Powell of Children’s Memorial Hospital in Chicago.

“We were seeing physicians in private hospital emergency departments that were doing this for everybody,” she told Reuters. Yet the findings demonstrated “that half the kids that were determined to be dehydrated do fine without it.”

Both treatments are expensive.

At Children’s Memorial Hospital, where the study was done, treating a child with an IV costs $125. One Zofran tablet, which dissolves on the tongue, costs $36.

“If you avoid putting an IV in a child, you’re saving a lot” in addition to preventing the pain of a needle, Powell said.

The number of children who needed to be hospitalized for their dehydration was the same in each group. The study excluded severely dehydrated children.

Powell, a pediatric emergency medicine physician, said up to 10 percent of the children brought into her emergency room, especially during the winter months, are suffering from childhood gastroenteritis. As many as 1 in 4 also have dehydration, which leaves them lethargic with a dry mouth and unable to make tears.