SAN DIEGO (AP) — Cadence Pharmaceuticals Inc. has asked the FDA to approve its drug candidate Acetavance, a form of the painkiller acetaminophen that is given intravenously. Cadence filed a New Drug Application with the FDA, formally requesting marketing approval for Acetavance as a treatment for acute pain and fever. The San Diego, Calif., company said that Acetavance would be the only intravenous drug approved to treat fever, and the first new intravenous painkiller approved in more than 20 years, pending the FDA’s ruling.