Parents have been warned not to give their children the anti-viral drug Tamiflu because the risks outweigh the benefits.

Researchers at Oxford University said otherwise healthy children should not be given the drug and GPs should not consider medications such as Tamiflu and Relenza to be the "magic bullet" during the current swine flu pandemic.

They said Tamiflu can cause vomiting in some children and this can lead to dehydration and other complications.

Instead, the advice to parents of children with a mild form of swine flu is to give them cool drinks and ensure they have lots of rest.

The warning comes as 16 students were sent home from two Irish colleges in the Donegal Gaeltacht yesterday after presenting with swine flu symptoms. All 300 students at another college were sent home at the weekend following an outbreak of the flu.

The Republic's Health Services Executive has included children under five years in its list of high-risk groups alongside pregnant women, those aged over 65 and patients with chronic health conditions. It recommends that only these groups receive anti-viral treatment.

However, the Department of Health cautioned against applying the findings of the UK report, which was done in the context of seasonal flu, to swine flu.

It said anti-viral guidance follows the advice of the national influenza expert group and is based on a "careful balancing of the risks and benefits". British health authorities offer Tamiflu to anyone with flu symptoms.

"Anti-viral therapy is only routinely recommended in Ireland for those with severe illness or for those who are in defined high-risk groups and all cases will be based on clinical judgment," explained a spokesman.

"The vast majority of patients will have a mild self-limiting illness which can be managed at home with usual over the counter medicines and anti-viral treatment is not required in such cases."

However, the Oxford researchers believe that their findings extend to the current swine flu outbreak. Their report analysed the results of four previous studies involving over 1,700 children aged between one and 12 years.

They found that while Tamiflu helped to shorten illness by around one day and reduced the spread of flu within the household, it had little or no effect on asthma attacks, ear infections and the likelihood of a child needing antibiotics.

Dr Carl Henegan, a clinical lecturer and member of the research team, said it was "inappropriate" to give children Tamiflu when they have only a mild form of the illness.

"The downside of the harms outweigh the one-day reduction in symptomatic benefits," he said.

He advised GPs not to think of Tamiflu as a "magic bullet" and warned that widespread use of the drug could lead to the flu becoming resistant to it.

In a statement, Roche, the pharmaceutical company which makes Tamiflu, said there was "significant data" to show the effectiveness of the medicine; however, with all medicines "healthcare professionals need to "weigh up the benefits against the risk of any side effects".

In the latest outbreak of swine flu, 14 students staying in one house at Colaiste Bhride in Ranafast were sent home after five had shown symptoms of the virus. And at a Gael Linn college in Magheraroarty, 18km away, a further two students were sent home yesterday as a "precautionary measure".

The results of tests carried out on the suspected cases in both colleges are expected to be known later this week.

Both colleges remain open and are continuing with classes as normal.