In palliative care, a lengthy tradition of using morphine rescue doses as a supplement to the typical prescribed morphine dose exists; it has historically been given every four hours to provide coverage during the entire 24-hour day.The typically administered rescue dose was equal to either a half-dose or full 4-hour dose, which represents 1/6 or 1/12 of the total morphine dose over 24 hours.

The availability of “modified” slow release molecules has simplified background analgesia treatment. Patient compliance and comfort are increased, as the patient only needs to take two capsules per 24 hours or change a transdermal patch every 72 hours to ensure background analgesia.

The use of short-acting, immediate release morphine still has its place; the dose is calculated as a proportion of the 24 hours base dose.The goal is to noticeably but temporarily increase the base opioid levels to relieve this breakthrough pain.However rescue dose dosage has gotten more complicated because of the availability of multiple morphine-like molecules and occasional concurrent usage.