A rapid increase in purchases by two big AIDS relief programs is stretching supplies of two treatments and will likely lead to shortages of the drugs for patients in developing countries, the Wall Street Journal reports.

Bristol-Myers Squibb Co., which makes both drugs, and Merck & Co., which markets one of them in developing countries, attributes the shortages to increased orders from an acceleration in the Bush administration's $15 billion Emergency Program for AIDS Relief (Pepfar) and rising demand from the Global Fund to Fight AIDS, Tuberculosis and Malaria, as well as several other organizations.

The companies say it is difficult to predict how long the shortages of the drugs, stavudine (which is sold under the brand name Zerit) and efavrienz (which is marketed in developing countries under the name Stockrin), will persist. "Our goal is to maintain uninterrupted supply for current patients, while accelerating production to meet the forecasted increase in demand from new patients," said Merck in a statement.

In addition to increased demand for the drugs, supplies in developing countries are low because of the recent withdrawal of generic versions made by two Indian companies after the World Health Organization withdrew its approval of the drugs. The short supply raises the question of whether the U.S. government, which requires all medications supplied through Pepfar to be approved by the Food and Drug Administration, will approve more generic AIDS drugs for international use. "The generics have this stuff in a warehouse," said Bill Haddad, CEO of biotech research company Biogenerics Inc and an advocate for approval of generics.

More than 45 million people worldwide are infected with HIV, and 95 percent of them live in developing countries, according to estimates supplied by the Global Fund.

"This is psychological torture to get patients worried that there will not be enough drugs," said Peter Mugyenyi, the director of the Joint Clinical Research Centre in Kampala, Uganda. "AIDS is not an overnight disease. The numbers didn't just materialize. It's not acceptable to run short of the drug when huge numbers of people are dying."