Morphine for Severe Cancer Pain from Stomach Tumor
Yes, give her morphine—it is the first-choice opioid for moderate to severe cancer pain and should be started immediately using oral immediate-release formulations for dose titration. 1
Initial Dosing Strategy
Start with oral immediate-release morphine 20-40 mg every 4 hours, with the same dose available as a "rescue" dose for breakthrough pain (can be given up to hourly). 2 This approach allows rapid titration to effective pain control while minimizing the risk of overdosing. 1
- The oral route is optimal and should be your first choice unless the patient cannot swallow. 1
- Morphine has no ceiling effect for analgesia—doses can be increased as needed to achieve pain relief. 1
- Review the total daily morphine dose (regular + rescue doses) every 24 hours and adjust the regular dose upward accordingly. 1
Dose Titration Process
- If pain returns consistently before the next scheduled dose, increase the regular dose immediately. 1
- Do not wait more than 24 hours to adjust dosing in acute severe pain situations. 1
- If the patient requires more than 4 breakthrough doses in 24 hours, increase the baseline regular dose. 2
- Breakthrough doses should remain at 10-15% of the total daily dose. 2
Transition to Maintenance Therapy
Once pain is controlled (typically after 2-3 days of titration):
- Calculate the total daily morphine requirement (regular doses + all rescue doses used). 1
- Convert to a modified-release (long-acting) formulation given every 12 hours. 1
- Continue providing immediate-release morphine for breakthrough pain at 10-15% of the total daily dose. 2
- A double dose of immediate-release morphine at bedtime prevents nighttime awakening from pain. 1
Alternative Routes if Oral Not Feasible
If the patient cannot take oral medication due to severe nausea, vomiting, or bowel obstruction from the stomach tumor, use subcutaneous morphine. 1
- The oral-to-subcutaneous conversion ratio is 3:1 (divide the oral dose by 3). 2
- For urgent severe pain requiring immediate relief, intravenous boluses of 1.5 mg every 10 minutes achieve faster pain control (84% relief at 1 hour vs. 25% with oral). 2
- Avoid intramuscular administration—it is more painful and offers no advantage over subcutaneous. 1
Essential Side Effect Management
Prescribe a stimulant laxative prophylactically from day one—constipation is inevitable and worsens over time. 3 This is the most common pitfall in morphine therapy.
- Nausea and vomiting are common initially but typically decrease after the first few weeks. 4, 5
- Consider prophylactic antiemetics for the first 5-7 days. 2
- Drowsiness and cognitive effects usually improve with continued use. 2
Critical Warnings and Monitoring
- No upper dose limit exists for morphine—the correct dose is whatever controls pain with tolerable side effects. 2
- In patients with renal impairment, reduce both dose and frequency due to accumulation of active metabolites. 2
- Monitor for respiratory depression, especially in the first 24 hours after initiation or dose increases. 6
- Ensure the patient has no contraindications: severe respiratory disease, bowel obstruction (if using oral route), or known morphine allergy. 7
Common Pitfalls to Avoid
- Do not use inadequate breakthrough dosing (must be 10-15% of total daily dose, not a fixed low amount). 2
- Do not abandon morphine prematurely due to side effects—manage them appropriately rather than switching agents unnecessarily. 2
- Do not delay dose escalation when pain persists—there is no arbitrary maximum dose. 1
- Do not forget laxative prophylaxis—this is non-negotiable. 3, 2
Special Consideration for Stomach Tumors
While morphine is the standard first-line agent, be aware that patients with severe gallbladder or hepatobiliary disease may require alternative approaches. 3 However, for a stomach tumor causing severe pain, morphine remains appropriate with individual dose titration using immediate-release formulations. 3