Magnesium is implicated in the activation of NMDA receptors by amino-excitatory acids in the central nervous system [1]. Magnesium deficiency is associated to an increased activation of these receptors, and to an increased sensitivity to pain in animals. Spinal cord is the site of sensitization of pain, mainly mediated by the NMDA receptors, and intrathecal magnesium may have anti-hyperalgesic effect when administered intrathecally [2]. As intrathecal magnesium has already been used in humans for treatment of eclampsia, we stated that it could also improve postoperative analgesia and reduce the need for auto-administered morphine if given (50 mg of magnesium sulfate) with the intrathecal anesthetic drugs (bupivacaine and sufentanil) injected for orthopedic surgery.
Primary Outcome Measures:
- Reduction of morphine consumption in the postoperative period. [ Time Frame: in the postoperative period ] [ Designated as safety issue: Yes ]
Secondary Outcome Measures:
- Duration of sensory and motor blockade induced by the intrathecal anesthesia ; side effects; postoperative pain (visual analogue scale). [ Time Frame: postoperative pain ] [ Designated as safety issue: Yes ]
| Estimated Enrollment: |
40 |
| Study Start Date: |
January 2004 |
| Estimated Study Completion Date: |
October 2008 |
| Estimated Primary Completion Date: |
October 2008 (Final data collection date for primary outcome measure) |
Magnesium is implicated in the activation of NMDA receptors by amino-excitatory acids in the central nervous system [1]. Magnesium deficiency is associated to an increased activation of these receptors, and to an increased sensitivity to pain in animals. Spinal cord is the site of sensitization of pain, mainly mediated by the NMDA receptors, and intrathecal magnesium may have anti-hyperalgesic effect when administered intrathecally [2]. As intrathecal magnesium has already been used in humans for treatment of eclampsia, we stated that it could also improve postoperative analgesia and reduce the need for auto-administered morphine if given (50 mg of magnesium sulfate) with the intrathecal anesthetic drugs (bupivacaine and sufentanil) injected for orthopedic surgery.
Purpose
