Pearls in acute pain management with opioids from Keith Dickerson, MS, MD:
Because IV opioids reach their peak effect within 15-30 minutes, patients may initially be reassessed and then re-dosed at this interval until adequate pain control is achieved and an effective dose is determined. The patient may then be placed on scheduled- or as-needed doses every two to three hours, or, alternatively, on a PCA pump. Doses may then be titrated by 25% for mild pain, by 50% for moderate pain, and by 100% for severe pain. “ (in this patient with uncontrolled pain, I would have considered the 50% or so increase if initial bolus really did nothing versus just repeating the same dose at the below mentioned 5 (to 15) minute interval…while monitoring respiration and O2 sat or end tidal CO2!)
Key points about morphine.
- The optimum single dose of morphine is yet to be determined.
- A standard single dose of morphine of 0.1 mg/kg is inadequate to control acute pain in the ED.
- Incremental titration of morphine with an initial loading dose of 0.1 mg/kg and subsequent dosages of 0.025 to 0.05 mg/kg every 5 minutes appears to be an acceptable alternative.
- A higher initial (loading) dose of morphine at 0.15-0.2 mg/kg given either in a single dose over a few minutes or in divided doses may have potential for adequate pain relief but warrants further research.
In an attempt to quantify the analgesic effect of a single 0.1-mg/kg dose of IV morphine, Bijur and colleagues showed that 67% of patients who received this dose reported less than 50% reduction in pain 30 minutes after administration. Thus, the standard 0.1-mg/kg dose of IV morphine is not adequate to control severe pain in most patients. In another study, 47% of patients presenting to the ED with painful conditions and who required IV opioids did not achieve 50% or greater reduction in pain 1 hour after administration of 0.1 mg/kg of morphine.
In a search for the optimum dose of IV morphine, Lvovschi and colleagues evaluated the effect of IV morphine titration in treating severe pain in the ED. The study authors implemented a protocol with an initial dose of 2 mg (body weight < 60 kg) or 3 mg (body weight > 60 kg) with subsequent administration of 3 mg of morphine every 5 minutes until desirable or adverse effects occurred. The results showed pain relief in 99% of patients with a mean dose of morphine of 10.4 ± 6.2 mg; that is, 0.15 ± 0.09 mg/kg given in 3 boluses.
Key points about hydromorphone.
- A single dose of IV hydromorphone (0.015 mg/kg) is suboptimal in treating acute pain in the ED.
- Titration with an initial bolus of 0.015 mg/kg and follow-up doses of 0.0075-0.015 mg/kg every 5-15 minutes might be a reasonable alternative, regardless of patient age.
- A loading dose of 0.03 mg/kg is promising, although it was associated with transient hypoxia in a single study.
- Further studies with larger loading doses of hydromorphone are needed, bearing in mind the severity of adverse effects of this opioid analgesic.