IV Morphine Dilution for 2-5 mg Doses
IV morphine 2-5 mg should be diluted in 4-5 mL of normal saline (PNSS) or D5W for administration. This dilution provides an appropriate concentration for safe intravenous administration while allowing for accurate dosing.
Dilution Guidelines for IV Morphine
Standard Dilution:
- For a 2-5 mg dose of morphine:
- Dilute in 4-5 mL of either PNSS or D5W
- Results in a concentration of approximately 0.4-1.25 mg/mL
Administration Considerations:
- Administer as a slow IV push over 4-5 minutes to minimize adverse effects 1
- The slow administration rate is particularly important to reduce the risk of respiratory depression and hypotension
Evidence-Based Rationale:
- Pediatric emergency guidelines recommend morphine doses of 0.15-0.25 mg/kg be infused over 10 minutes in D5W for conditions such as infundibular spasm 1
- When administering IV morphine for severe pain, boluses of 2-3 mg with 5-minute intervals between doses have been shown to be safe and effective 2
Clinical Applications
Pain Management:
- For acute severe pain, morphine can be titrated using 2-3 mg boluses at 5-minute intervals until pain relief is achieved 2
- For cancer pain, IV morphine provides more rapid relief than oral administration, with a 1:1 ratio between initial IV dose and subsequent oral dosing 3
Safety Considerations:
- While IV administration provides faster onset of analgesia (5 minutes) compared to IM (20 minutes), it may cause slightly more sedation and respiratory effects 4
- Monitor vital signs, especially respiratory rate, during and after administration
- Have naloxone readily available for reversal if needed
Important Precautions:
- D5W is compatible with morphine and is often preferred when administering with other medications
- PNSS (normal saline) is also compatible and commonly used
- Avoid rapid IV push as this increases risk of adverse effects including hypotension and respiratory depression
- For continuous infusions, different dilution protocols apply (typically more dilute)
The recommended 4-5 mL dilution volume provides a balance between maintaining a reasonable concentration while allowing for controlled administration that minimizes adverse effects.