The Associated Press reports that a panel of federal health rejected the use of two drugs from Merck and GlaxoSmithKline to prevent prostate cancer, saying the drugs could actually raise the risk of the most serious types of tumors. The Food and Drug Administration panel of cancer experts voted 17-0 with one abstention that the risks of Merck''s Proscar outweighed its benefits. In a similar vote, the panel voted 14-2 with two abstentions against GlaxoSmithKline PLC''s Avodart. Both drugs are already approved to treat enlarged prostate. The FDA is not required to follow the panel''s advice, but often does. Studies by both companies showed their drugs decreased incidence of low-grade prostate tumors by nearly 25 percent.