Combined Intrathecal Morphine and Dexmedetomidine Analgesia

Opioids, administered intrathecal or epidural, are widely used for postoperative, and chronic nociceptive pain secondary to cancers. Intrathecal injection of morphine to provide postoperative analgesia during the initial 24 h after operation is a widely used technique.The Human studies on the antinociceptive effects of co-administrated intrathecal morphine and dexmedetomidine in postoperative pain are still lacking. In this study, the investigators aimed to compare the synergistic interaction and side-effects of combined intrathecal morphine and dexmedetomidine with either drug alone for postoperative analgesia in cancer patients undergoing major abdominal surgery. Patients were randomly allocated into three groups of 30 patients each to receive either; hyperbaric bupivacaine 0.5% (Group I/Bupivacaine Group), bupivacaine and 0.5 mg morphine (Group II/Morphine Group), bupivacaine and 0.5 mg morphine plus 5 µg of dexmedetomidine (Group III/Morphine-DEX Group). The assigned drugs were dissolved in 1ml physiological saline and administered intrathecal with bupivacaine before induction of general anesthesia.

Inclusion criteria

• major abdominal cancer surgery (e.g. hemi-colectomy or cystectomy)

Exclusion criteria

• known allergy to study drugs
• Significant cardiac, respiratory, renal or hepatic disease.
• 2nd or 3rd degree heart block.
• Coagulation disorders.
• Low back pain or other back problems.
• Drug or alcohol abuse.
• BMI>30kg\\m2.
• Psychiatric illnesses that would interfere with perception and assessment of pain.