Effects of intravenous sodium amobarbital vs lidocaine on pain and sensory abnormalities in patients with spinal cord injury.

OBJECTIVE

To compare the responses of patients with spinal cord injury (SCI) in regards to pain and sensory abnormalities to single blinded intravenous (i.v.) infusions of normal saline, sodium amobarbital, and lidocaine.

SETTING

Inpatient pain unit.

STUDY

DESIGN

Retrospective chart review.

METHODS

Demographic data, body maps marking pain areas, pain ratings, standardized history and detailed examination were collected on admission in 5 patients with SCI and pain. i.v. normal saline was followed by either i.v. sodium amobarbital or lidocaine, respectively, (patients, but not the administering physician, were blinded to the order of the drugs). Spontaneous pain ratings and sensory abnormalities to light touch, pinprick and cold were documented at baseline and immediately after each infusion.

RESULTS

Sodium amobarbital decreased spontaneous pain by 73% (vs 46% with lidocaine) and normalized sensory abnormalities at or above the level of injury in 3 patients (as compared to just 1 patient with lidocaine), 2 of whom had transitional zone allodynia/hyperalgesia.

CONCLUSION

In this small study, the analgesic effect of sodium amobarbital and its ability to modify sensory abnormalities appeared superior to that of lidocaine.