SINGAPORE : Drug company Roche said sales of anti-viral drug Tamiflu have gone up in tandem with flu cases this year.

Tamiflu is not just being stockpiled to fight against the avian flu, but also prescribed to patients down with severe flu.

When Dr Chong Yeh Woei sees patients with severe flu, he takes no chances, sending their blood samples for tests.

And he has had to do more of it recently as more patients come in with bad bouts of flu, some even developing into pneumonia.

"In the last two months, (I've) prescribed maybe about 10 to 20 doses of Tamiflu. Most of them were very, very ill... and therefore we had to use that to solve their problem.

"If we get the diagnosis of infleunza right clinically, the results of Tamiflu can be quite spectacular... they get well very quickly," said Dr Chong, Atriamed Associates.

The National University Hospital, on the other hand, said it has not dispensed Tamiflu, but acknowledged that using anti-virals within 48 to 72 hours of the onset of viral flu can be beneficial.

Raffles Medical Group said that makes Tamiflu popular among senior managers who said they cannot afford to be down with flu, as "time lost means money loss."

"It's not a drug you would use casually; it's something you use judiciously and carefully, and preferably in very, very sick patients," cautioned Dr Chong.

The World Health Organisation said seasonal flu is now showing resistance to Tamiflu in 15 per cent of cases worldwide.

With the flu season expected to set in from next month, doctors and patients will have to balance this issue of resistance, against treating a viral flu quickly and effectively.

The MOH does not have guidelines on the use of Tamiflu on seasonal flu, but said it is not common practice.

The ministry advised instead that the elderly and younger children get their annual influenza vaccinations. - CNA /ls