WASHINGTON — Medicare says it’s planning to tighten oversight of opioid drugs prescribed to millions of elderly and disabled beneficiaries.

Under a proposal released Thursday, patients would have to consult their doctor and get approval from their drug plan if a new prescription puts them above recommended cumulative dose levels for morphine-like painkillers. Pharmacists could still dispense a 7-day supply of medication.

Medicare will also limit initial prescriptions of opioid drugs for treating pain after surgery or an injury, for example to a 7-day supply.

The changes would take effect next year.