Some researchers in Thailand are saying that H5N1, also refered to as birdflu or avainflu should be treated with higer doses of Tamiflu.
However United States based researchers are saying that this will result in the virus becoming resistant to Tamiflu instead.
From Reuters article:
The H5N1 has infected 433 people around the world since 2003, killing 262 of them, according to the latest tally by the World Health Organisation. The WHO recommends treating patients with Roche AG's (ROG.VX) Tamiflu at a dose of 75 mg twice daily for five days.