However, short-term studies suggest that amprenavir does not increase triglyceride and cholesterol levels as significantly as other protease inhibitors. Increasing attention has been given to changes in body composition. Typically people reporting this change in body fat are not complaining of overall weight loss, but rather a redistribution of their body fat. Collectively, these changes are called lipodystrophy. The association of body composition changes and use of anti-HIV therapy remains unclear, though it is clear the incidence of these problems has increased since the availability of protease inhibitors.
Australian researchers believe protease inhibitors interfere with the way the body processes fats.
A somewhat similar mechanism is claimed by scientists working for Glaxo Wellcome, the manufacturer of amprenavir. However, the Glaxo Wellcome scientists claim to have identified two separate mechanisms, one caused by one of the protease inhibitors and a second caused by the other three. In their view, neither mechanism is caused by amprenavir. Although so far a low incidence of lipodystrophy has been reported in amprenavir studies, it is too early to draw any strong conclusion about the drug's role in causing these problems. These conditions have been documented in both women and men living with HIV in the pre-protease era.