In the spring of 2000, a professional guitarist named Diana Levine, then in her 50s, sought treatment for a migraine headache at a clinic in Vermont. She usually received the drug Demerol for pain relief, along with an injection of Wyeth’s anti-nausea drug Phenergan in the muscles of her butt to relieve the nausea that usually accompanies migraines. But this time the physician’s assistant used an alternative method for administering Phenergan approved by the Food and Drug Administration.