How the dose is calculated
Morphine is dosed per single administration by weight, not a total daily amount — the same weight-based dose is repeated at the interval shown, titrated to pain response.
Typical dosing by route
| Route | Dose | Frequency | Max single dose |
|---|---|---|---|
| IV/SC | 0.1 mg/kg | q2-4h prn | 10 mg |
| Oral | 0.3 mg/kg | q4h prn | 15 mg |
Always titrate to effect and respiratory status — start at the lower end of the range in opioid-naive patients, infants, or anyone with respiratory compromise, and have naloxone available.
Clinical use
- First-line strong opioid for moderate-severe acute pain (trauma, post-operative, sickle cell crisis) and in the WHO analgesic ladder for cancer/palliative pain.
- IV dosing is preferred when rapid, titratable analgesia is needed; oral dosing is used for ongoing/breakthrough pain once the acute phase has settled.
- Monitor respiratory rate and sedation level closely, especially with the first few doses or when combined with other sedating drugs.
Frequently asked questions
What is morphine used for?
Moderate to severe pain — trauma, post-surgical pain, sickle cell crisis, and cancer/palliative pain — where weaker analgesics are insufficient.
Why is the oral dose higher than the IV dose?
Oral morphine undergoes significant first-pass liver metabolism before reaching the bloodstream, so a larger oral dose is needed to achieve a comparable effect to a smaller IV dose.
What should be monitored after giving morphine?
Respiratory rate, oxygen saturation, and sedation level — opioid-induced respiratory depression is the main serious risk, and naloxone should be available to reverse it if needed.
References
- World Health Organization. WHO Guidelines on the Pharmacological Treatment of Persisting Pain in Children with Medical Illnesses.
- British National Formulary for Children (BNFc) — Morphine.