Effect of lumbar-epidural administration of tramadol on lower urinary tract function.
OBJECTIVE
Intrathecal and epidural administration of micro-agonist opioids is associated with urinary retention, a potentially serious adverse-event. In animal studies tramadol has been found not to affect voiding function. We evaluated urodynamic effects of epidural tramadol in humans.


METHODS
Fifteen adults planned for cystoscopy under local-anesthesia underwent urodynamics (UDS) at baseline and 30 min after administration of 100 mg tramadol in lumbar-epidural space. UDS consisted of filling cystometry, pressure-flow study and pelvic floor electromyography (EMG). Subsequently, all underwent cystoscopy and were observed for 6 hr.


RESULTS
After injection of tramadol, a significant rise was observed in bladder capacity (391.8 +/- 179.6 ml vs. 432.7 +/- 208.8 ml; P = 0.019) and compliance (60.1 +/- 51.5 ml/cm H(2)O vs. 83.0 +/- 63.0 ml/cm H(2)O; P = 0.011) without a significant change in filling pressure (22.5 +/- 13.2 cm H(2)O vs. 24.1 +/- 15.1 cm H(2)O; P = 0.576). Filling sensations were delayed significantly (P < or = 0.05). EMG during filling phase showed a significant fall (P = 0.027). Peak flow-rate (Q(max)), average flow-rate, postvoid residue and detrusor pressure-at-Q(max) did not show significant change from baseline (P > 0.05). Three patients had bladder outlet obstruction which did not worsen after the injection. Guarding reflex was inhibited in seven out of 12 patients who had it at baseline (P = 0.016).


CONCLUSIONS
Epidural tramadol increases the bladder capacity and compliance and delays filling-sensations, without ill effect on voiding. This seems true even for patients with obstructed outflow; however, due to small number of patients a definite conclusion cannot be derived. These results will guide clinician to avoid catheterization in cases where epidural tramadol is used for postoperative pain. The inhibitory effects of tramadol on EMG activity are intriguing and need further studies.
Singh
S K
SK
Department of Urology, Postgraduate Institute of Medical Education and Research, Chandigarh, India. shrawanksingh2002@yahoo.com
Agarwal
M M
MM
Batra
Y K
YK
Kishore
A V K
AV
Mandal
A K
AK
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000494:pharmacology*; D004576:Electromyography; D005260:Female; D006801:Humans; D007268:Injections, Epidural; D008159:Lumbar Vertebrae; D008297:Male; D008875:Middle Aged; D012727:Sex Characteristics; D014147:Tramadol / Q000008:administration & dosage / Q000494:pharmacology*; D001743:Urinary Bladder / Q000187:drug effects / Q000502:physiology; D014551:Urinary Tract / Q000187:drug effects; D014553:Urinary Tract Physiological Phenomena / Q000187:drug effects*; D014554:Urination / Q000502:physiology; D014563:Urodynamics / Q000187:drug effects / Q000502:physiology
D000701:Analgesics, Opioid; D014147:Tramadol