WASHINGTON (AP) — The head of the Food and Drug Administration says a government review of prescription opioid medications, including their risks and contribution to the U.S. overdose epidemic, is still underway. Dr. Robert Califf said Tuesday that the FDA is still studying “what revisions are needed to support appropriate use” of opioid painkillers like OxyContin and Vicodin. He gave the update in a blog post outlining the FDA’s ideas for combating drug misuse and addiction. Califf promised to conduct a full review of FDA’s approach to opioids, including their prescribing instructions, to clinch Senate confirmation early this year.