Doctors should stop giving Tamiflu to children as a routine treatment for swine flu, researchers concluded after finding the drug can cause more harm than good.
Analysis revealed antiviral drugs speeds up children's recovery from flu but the side effect of vomiting can cause dehydration and other complications.
Researchers who carried out the study called on the Department of Health to halt the practice of Tamiflu and other antivirals being handed out as a matter of course to children with flu.
It should, they said, only be given to children aged 12 and under in exceptional circumstances such as when flu represents a serious risk to the well-being because of an underlying condition.
Equally, they said, there is a serious risk that if antivirals are overused the swine flu virus will develop resistance to Tamiflu by the time a second wave of swine flu is expected to sweep the country in the autumn.
The findings, published in the British Medical Journal, come shortly after another study revealed more than half the children who took Tamiflu suffered side effects such as nausea and nightmares.
Dr Matthew Thompson, of the University of Oxford and a GP, said that for most children the benefits of getting better half a day to a day and a half quicker than without antivirals were outweighed by the misery of the side effects.
He maintained it would be better for children to nurse their symptoms in bed a little longer rather than take Tamiflu when the symptoms were relatively mild.
"Parents are used to dealing with mild respiratory ailments. It's something every parent is familiar with. Children with mild flu are going to have a fairly small benefit from antivirals," he said.
"With every medication it's a balance between the potential benefits and the potential harm. The benefits of these are fairly small – it's about a day's shorter illness."
Instead of being routinely prescribed, he said a "targeted approach" would be a much better use of the drugs, especially as the study found the drugs had little or no effect in preventing asthma flaring up or ear infections setting in.
With 13 people having to take antivirals to prevent one person getting flu it was concluded the drugs had only a limited effect in halting transmission of the disease, bringing into question the decision to hand out Tamiflu at schools and other organisations earlier this year in a bid to stop swine flu spreading.
The study was carried out jointly with Dr Carl Heneghan, also of the University of Oxford and a GP, who called on ministers to change the rules on handing out antivirals to children during the swine flu outbreak.
Officials at the Department of Health refused yesterday to halt the use of Tamiflu. A spokesman said: "While there is doubt about how swine flu affects children, we believe a safety-first approach of offering antivirals to everyone remains a sensible and responsible way forward. However, we will keep this policy under review as we learn more about the virus and its effects."