What is the recommended protocol for morphine infusion in severe pain management?

Morphine Infusion Protocol for Severe Pain Management

For severe pain requiring rapid control, initiate intravenous morphine titration with 1.5 mg bolus doses every 10 minutes until pain relief is achieved, then transition to continuous infusion or scheduled dosing based on total requirements. 1

Initial Route Selection

Intravenous administration is the preferred route when rapid pain control is needed in severe pain. 1

• Subcutaneous route should be first-choice for patients unable to take oral opioids when rapid titration is not required 1
• IV route is indicated when subcutaneous administration is contraindicated (peripheral edema, coagulation disorders, poor peripheral circulation, need for high volumes/doses) 1
• Subcutaneous and intravenous routes show similar efficacy for continuous infusion, though IV provides faster pain relief 1

IV Titration Protocol for Severe Pain

Starting dose for opioid-naïve adults:

• 1.5 mg IV bolus every 10 minutes until pain relief or adverse effects occur 1
• Alternative FDA-approved dosing: 0.1-0.2 mg/kg every 4 hours, adjusted for severity 2
• For patients under 60 kg: 2 mg boluses every 5 minutes 3
• For patients over 60 kg: 3 mg boluses every 5 minutes 3

Expected outcomes with IV titration:

• 84% of patients achieve satisfactory pain relief within 1 hour (vs. 25% with oral morphine) 1
• 97% achieve relief by 12 hours 1
• Median dose to achieve relief: 4.5 mg IV (range 1.5-34.5 mg) 1

Transition to Maintenance Infusion

After successful titration, convert to continuous infusion or scheduled dosing:

• Calculate total IV morphine used during titration 1
• For continuous IV infusion: Use hourly rate based on 24-hour requirements 1, 4
• For scheduled dosing: Convert to oral morphine using 1:3 ratio (IV:oral) 1
• The ratio of initial IV dose to subsequent oral dose centers around 1:1 after stabilization 5

Continuous infusion dosing:

• Starting infusion rates typically range from 0.5-300 mg/hour depending on prior requirements 4
• For opioid-naïve patients in palliative care: start at 2 mg IV bolus, titrate to effect 1
• Adjust infusion rate based on bolus requirements: if patient needs 2 boluses in one hour, double the infusion rate 1

Breakthrough Dosing During Infusion

Provide rescue doses for breakthrough pain:

• Bolus dose = 2 times the hourly infusion rate for morphine/hydromorphone 1
• Order IV morphine/hydromorphone boluses every 15 minutes as needed 1
• Order IV fentanyl boluses every 5 minutes as needed 1
• If more than 4 rescue doses per day are needed, increase baseline infusion 1

Special Populations

Renal impairment:

• Start with 25-50% of usual dose due to accumulation of active metabolites 6, 2
• Consider buprenorphine as safer alternative in chronic kidney disease stages 4-5 (eGFR <30 mL/min) 1

Hepatic impairment:

• Start with lower doses and titrate slowly while monitoring for side effects 2

Elderly patients:

• Use caution with dose selection, starting at low end of dosing range 2
• Consider starting dose of 10 mg/day oral equivalent (vs. 15 mg/day in younger patients) 7

Pediatric patients:

• Safety and effectiveness not established in patients under 18 years 2
• Limited data suggests 0.034-0.06 mg/kg/hour for continuous subcutaneous infusion in terminal illness 8

Critical Safety Considerations

Avoid these common pitfalls:

• Never administer rapidly - slow IV injection is mandatory to prevent chest wall rigidity 2
• Take extreme care with dosing calculations between different concentrations and between mg and mL to prevent fatal overdose 2
• Always include both total dose in mg AND volume when prescribing 2
• Limit administration to providers familiar with managing respiratory depression 2

Monitor for serious adverse events:

• Respiratory depression, apnea, circulatory depression (most serious) 2
• Morphine-induced adverse events occur in 11% of patients during titration 3
• Common effects: sedation, nausea, vomiting, constipation 2
• High doses may cause CNS excitation and convulsions 2

Side Effect Management

Prophylactic measures:

• Always prescribe laxatives prophylactically - constipation is the most persistent side effect 1, 6
• Order antiemetics PRN - nausea/vomiting occurs in up to two-thirds of patients initially but usually resolves 1, 6

If intolerable side effects develop:

• Consider opioid rotation to alternative strong opioid 1
• Dose reduction may alleviate refractory effects 1
• CNS toxicity (hallucinations, myoclonus, hyperalgesia) particularly benefits from opioid switching 1

Contraindications

Do not use morphine IV in:

• Known hypersensitivity or allergy to morphine 2
• Bronchial asthma or upper airway obstruction 2
• Respiratory depression without resuscitative equipment available 2
• Paralytic ileus 2