Vioxx Withdrawal Raises Concern About FDA By DIEDTRA HENDERSON     WASHINGTON (AP) -- Americans should feel reasonably safe taking government-approved prescription drugs - with a few caveats - even after a popular arthritis medication was pulled from the market, medical experts say. But the problems with Vioxx raise questions about the Food and Drug Administration's safety review process and the length of time it took Merck to pull the drug, observers say...