The analgesic effect of oral morphine or pentazocine for extracorporeal shock wave lithotripsy.

Background: Extracorporeal shock wave lithotripsy (ESWL) in these days is usually carried out on ambulatory or outpatient basis. With the application of a lithotriptor of modern version an appropriate yet cost-effective analgesia with minimal side effects for ESWL is mandatory.

Methods: The analgesic effect of oral morphine (30 mg) was compared with that of pentazocine (100 mg) in a prospective study comprising 100 patients undergoing ESWL with a lithotripter of improved version for urinary tract stones. All patients received orally lorazepam 1 mg as sedative together with the appointed tested drug 30 min before the procedure. The analgesic effects of both drugs were assessed having recourse to the pain scale and efficacy scale.

Results: There were 94% of patients in the pentazocine (mixed agonist-antagonist) group who felt satisfied with the regimen and stood the procedure well without resort to supplemental drug, as compared with the morphine (potent mu-agonist) group in which only 70% of patients did so. Although the adverse effect such as dizziness was found in the pentazocine group, the degree of sleepiness produced by its deeper sedation effect was to the advantage of patients during the lithotripsy procedure. There were no significant changes in intergroup mean blood pressure (MBP), but heart rate (HR) was higher and O2 saturation (SpO2) was lower in the pentazocine group after treatment. Both narcotics did not induce renal colic in our study. Also, pentazocine 100 mg plus lorazepam 1 mg given orally did not induce psychotomimetic reaction intraoperatively or postoperatively.

Conclusions: We concluded that oral pentazocine at 100 mg plus lorazepam 1 mg, could offer satisfactory analgesia in patients undergoing ESWL for urinary tract stones with a lithotripter of improved version.