Clinical trial NCT00560092: Intrathecal Magnesium and Postoperative Analgesia
Official title: Effects of a Single Dose of Intrathecal Magnesium Sulfate on Postoperative Morphine Consumption After Total Hip Replacement
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: PHASE3
Conditions: Total Hip Replacement
Keywords: Magnesium
Pain
Morphine
Intrathecal
NMDA
Elective total hip replacement under intrathecal anesthesia
Lead sponsor: University Hospital, Clermont-Ferrand
Sponsor class: OTHER
First posted: 2007-11-19
Enrollment: 40
Sex: ALL
Minimum age (years): 56
Maximum age (years): 93
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: SINGLE_GROUP
Primary purpose: TREATMENT

Brief summary: 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.

Detailed description: 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.

Eligibility criteria: Inclusion Criteria:

* Total hip replacement under intrathecal anesthesia.

Exclusion Criteria:

* General anesthesia (alone or not)
* Intolerance to morphine
* Misunderstanding of the use of the device for intravenous patient-controlled administration of morphine.

Primary outcomes:
measure: Reduction of morphine consumption in the postoperative period.
timeFrame: in the postoperative period
Secondary outcomes:
measure: Duration of sensory and motor blockade induced by the intrathecal anesthesia ; side effects; postoperative pain (visual analogue scale).
timeFrame: postoperative pain
Other outcomes:
Locations:
city: Clermont-Ferrand
country: France
facility: Clermont-Ferrand University Hospital
state: Auvergne
Study officials:
affiliation: University Hospital, Clermont-Ferrand
name: Christian Duale, Dr
role: PRINCIPAL_INVESTIGATOR
References:
citation: Mayer ML, Westbrook GL. Permeation and block of N-methyl-D-aspartic acid receptor channels by divalent cations in mouse cultured central neurones. J Physiol. 1987 Dec;394:501-27. doi: 10.1113/jphysiol.1987.sp016883.
citation: Buvanendran A, McCarthy RJ, Kroin JS, Leong W, Perry P, Tuman KJ. Intrathecal magnesium prolongs fentanyl analgesia: a prospective, randomized, controlled trial. Anesth Analg. 2002 Sep;95(3):661-6, table of contents. doi: 10.1097/00000539-200209000-00031.