Anesth Analg 2004;98:846-850
© 2004 International Anesthesia Research Society
doi: 10.1213/01.ANE.0000099362.01312.3A
REGIONAL ANESTHESIA
The Effect of Short-Term Epidural Local Anesthetic Blockade on Urinary Levels of Substance P in Interstitial Cystitis
Andrew Sukiennik, MD,
Daniel B. Carr, MD,
Iwona Bonney, PhD,
James E. Marchand, PhD,
Heinrich Wurm, MD, and
Grannum R. Sant, MD*
Departments of Anesthesia and *Urology, Tufts-New England Medical Center, Boston, Massachusetts
Address correspondence to Iwona Bonney, PhD, Department of Anesthesia, Tufts-New England Medical Center, Box # 298, 750 Washington Street, Boston, MA 02111. Address email to IBonney{at}tufts-nemc.org
We investigated the effect of epidural local anesthetic blockade on urinary substance P levels in five patients suffering from painful flare-ups of interstitial cystitis. Urine was collected in 24-h intervals commencing at the onset of an epidural bolus of 0.25% bupivacaine followed by maintenance epidural infusions of 0.05% bupivacaine. Substance P was measured by radioimmunoassay. After initiation of the epidural infusion, urinary substance P levels increased and then declined in all patients. All patients reported a decrease in pain intensity. We hypothesize that acute release, followed by depletion, of substance P from bladder sensory nerve endings accounts for the transient increase of peptide levels in urine and may contribute to the decrease in pain intensity during a 3-day epidural infusion.
IMPLICATIONS: Substance P levels in urine initially increased and then declined in a series of 5 patients who achieved pain control by epidural local anesthetic infusion during a flare-up of interstitial cystitis.
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