Fares, K.M., Mohamed, S.A., & Abdel-Ghaffar, H.S. (2014). High dose intrathecal morphine for major abdominal cancer surgery: A prospective double-blind, dose-finding clinical study. Pain Physician, 17, 255–264.

To investigate the safety and efficacy of three doses of intrathecal morphine in patients receiving major abdominal surgery

Patients were randomly assigned to receive 0.2 mg, 0.5 mg, or 1 mg of morphine injected into the L3-4 space prior to anesthesia. All patients received the same type of anesthesia and reversal. Vital signs and Visual Analog Scales for pain were assessed at six, 12, 18, 24, 36, 48, and 72 hours postoperatively. At patient request, or for a pain score greater than or equal to 3, rescue analgesia of 100 mg IV tramadol was given.

• N = 90  
• MEAN AGE = 50.45 years (range = 35–64 years)
• MALES: Not provided  
• FEMALES: Not provided
• KEY DISEASE CHARACTERISTICS: Patients had surgeries including pelvic excentration, hemicolectomy, sigmoidectomy, cystectomy, and hysterectomy. The majority of procedures were American Society of Anesthesiologists class 2.

• SITE: Single site  
• SETTING TYPE: Outpatient    
• LOCATION: Egypt

• PHASE OF CARE: Active antitumor treatment

Double-blinded, randomized trial

• Time till first analgesic request
• Total analgesic consumption
• Observers Assessment of Alertness/Sedation (OAA/S)
• Postoperative adverse effects
• Visual Analog Scale (VAS)

The mean time in hours till the first analgesic request was longer in those receiving 0.5 mg (22.13, p < 0.001) and 1 mg (30.83 , p < 0.001) of morphine. Mean total tramadol consumption also was lower in these groups (p < 0.001) with the lowest consumption in those receiving 1 mg (p < 0.04). For the first 18 hours postoperatively, those receiving higher doses of intrathecal morphine had lower pain scores (p < 0.02) than those receiving 0.2 mg. At 24 hours and beyond, there were no significant differences in pain scores among groups. More patients in the higher dose groups developed pruritus (p = 0.01). There were no other significant differences in overall adverse effects between groups. One older patient in the 1 mg dose group developed respiratory depression.

Doses of 0.5 mg and 1 mg intrathecal morphine preoperatively resulted in longer postoperative pain control and less analgesic consumption with nonsignificant differences in adverse effects compared to a dose of 0.2 mg.

• Small sample (< 100)
• Risk of bias (no control group)

The provision of high-dose intrathecal morphine preoperatively resulted in improved postoperative pain control among patients receiving major abdominal surgeries for cancer. Higher doses were associated with better pain outcomes for the first 24–48 hours after surgery. The administration of high-dose intrathecal morphine necessitated careful patient selection and strict postoperative monitoring.