- Larger doses may be required during chronic therapy
- PO Rect (Adults ≥50 kg): Usual starting dose for moderate to severe pain in opioid-naive patients: 30 mg every 3–4 hr initially or once 24-hr opioid requirement is determined, convert to extended-release morphine by administering total daily oral morphine dose every 24 hr (as ER capsules), 50% of the total daily oral morphine dose every 12 hr (as MS Contin), or 33% of the total daily oral morphine dose every 8 hr (as MS Contin). See equianalgesic chart, Equianalgesic Dosing Guidelines. Dose of ER capsules should not exceed 1600 mg/day because of fumaric acid in formulation.
- PO Rect (Adults and Children <50 kg): Usual starting dose for moderate to severe pain in opioid-naive patients: 0.3 mg/kg every 3–4 hr initially.
- PO (Children >1 mo): Prompt-release tablets and solution: 0.2–0.5 mg/kg every 4–6 hr as needed. Controlled-release tablet: 0.3–0.6 mg/kg every 12 hr.
- IM IV SC (Adults ≥50 kg): Usual starting dose for moderate to severe pain in opioid-naive patients: 4–10 mg every 3–4 hr. MI: 8–15 mg, for very severe pain additional smaller doses may be given every 3–4 hr.
- IM IV SC (Adults and Children <50 kg): Usual starting dose for moderate to severe pain in opioid-naive patients: 0.05–0.2 mg/kg every 3–4 hr; maximum: 15 mg/dose.
- IM IV SC (Neonates ): 0.05 mg/kg every 4–8 hr, maximum dose: 0.1 mg/kg. Use preservative-free formulation.
- IV SC (Adults ): Continuous infusion: 0.8–10 mg/hr; may be preceded by a bolus of 15 mg (infusion rates vary greatly; up to 80 mg/hr have been used).
- IV SC (Children >1 mo): Continuous infusion, postoperative pain: 0.01–0.04 mg/kg/hr. Continuous infusion, sickle cell or cancer pain: 0.02–2.6 mg/kg/hr.
- IV (Neonates ): Continuous infusion: 0.01–0.03 mg/kg/hr.
- Epidural (Adults ): Intermittent injection: 5 mg/day (initially); if relief is not obtained at 60 min, 1–2 mg increments may be made (total dose not to exceed 10 mg/day). Continuous infusion: 2–4 mg/24 hr; may ↑ by 1–2 mg/day (up to 30 mg/day).
- Epidural (Children >1 mo): 0.03–0.05 mg/kg, maximum dose: 0.1 mg/kg or 5 mg/24 hr. Use preservative-free formulation.
- IT (Adults ): 0.2–1 mg. Use preservative-free formulation.
