The effect of short-term epidural local anesthetic blockade on urinary levels of substance P in interstitial cystitis.
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.


CONCLUSIONS
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.
Departments of Anesthesia and Urology, Tufts-New England Medical Center, Boston, Massachusetts 02111, USA.
Andrew
A
Sukiennik
Daniel B
DB
Carr
Iwona
I
Bonney
James E
JE
Marchand
Heinrich
H
Wurm
Grannum R
GR
Sant
D000767:Anesthesia, Epidural / Q000009:adverse effects*; D000779:Anesthetics, Local / Q000009:adverse effects* / Q000627:therapeutic use; D002045:Bupivacaine / Q000009:adverse effects / Q000627:therapeutic use; D018856:Cystitis, Interstitial / Q000150:complications / Q000652:urine*; D006801:Humans; D010146:Pain / Q000188:drug therapy / Q000209:etiology; D010147:Pain Measurement; D011863:Radioimmunoassay; D013373:Substance P / Q000652:urine*
D000779:Anesthetics, Local; D013373:Substance P; D002045:Bupivacaine