Rates of adverse events of long-acting opioids in a state Medicaid program.

Background: Despite widespread use and emerging safety concerns, data on the comparative safety and effectiveness of long-acting opioid (LAO) analgesics are weak.

Objective: To compare rates of adverse events among patients newly prescribed an LAO.

Methods: A retrospective observational cohort study using Medicaid administrative claims data was conducted examining time until first adverse outcome among patients with new prescriptions for methadone, extended-release (ER) oxycodone, ER morphine, or transdermal fentanyl.