Effects of spasmolytic and/or non-steroidal antiinflammatory drugs on muscle hyperalgesia of ureteral origin in rats

Effects of PDE5 Inhibitors and sGC Stimulators in a Rat Model of Artificial Ureteral Calculosis

Urinary colics from calculosis are frequent and intense forms of pain whose current pharmacological treatment remains unsatisfactory. New and more effective drugs are needed to control symptoms and improve stone expulsion. Recent evidence suggested that the Nitric Oxide (NO) / cyclic guanosine monophosphate (cGMP) / phosphodiesterase type 5 (PDE5) system may contribute to ureteral motility influencing stone expulsion. We investigated if PDE5 inhibitors and sGC stimulators influence ureteral contractility, pain behaviour and stone expulsion in a rat model of ureteral calculosis. We investigated: a)the sex-specific PDE5 distribution in the rat ureter; b)the functional in vitro effects of vardenafil and sildenafil (PDE5 inhibitors) and BAY41-2272 (sGC stimulator) on induced ureteral contractility in rats and c)the in vivo effectiveness of vardenafil and BAY41-2272, alone and combined with ketoprofen, vs hyoscine-N-butylbromide alone or combined with ketoprofen, on behavioural pain indicators and stone expulsion in rats with artificial calculosis in one ureter. PDE5 was abundantly expressed in male and female rats’ ureter. In vitro, both vardenafil and BAY41-2272 significantly relaxed pre-contracted ureteral strips. In vivo, all compounds significantly reduced number and global duration of “ureteral crises” and post-stone lumbar muscle hyperalgesia in calculosis rats. The highest level of reduction of the pain behaviour was observed with BAY41-2272 among all spasmolytics administered alone, and with the combination of ketoprofen with BAY41-2272. The percentage of stone expulsion was maximal in the ketoprofen+BAY41-2272 group. The NO/cGMP/PDE5 pathway is involved in the regulation of ureteral contractility and pain behaviour in urinary calculosis. PDE5 inhibitors and sGC stimulators could become a potent new option for treatment of urinary colic pain.

Butylscopolammonium bromide does not provide additional analgesia when combined with morphine and ketorolac for acute renal colic

OBJECTIVE

To evaluate the effect of adding butylscopolammonium bromide (BB) to morphine and ketorolac in the treatment of acute renal colic in the ED.

METHODS

A prospective, double-blind, randomized controlled trial of i.v. triple therapy (morphine, ketorolac and BB) versus double therapy (morphine and ketorolac) in adult ED patients with a clinical diagnosis of acute renal colic and a pain rating greater than five on a 10 cm visual analogue scale (VAS). VAS was recorded at time 0, 20 and 40 min. Patients received rescue morphine at 20 or 40 min according to the protocol if needed. We compared pain reduction and the need for rescue analgesia at 4 min between two groups.

RESULTS

Eighty-nine patients were randomized over a 13 month period. A total of 46 (51.7%) patients received BB in addition to morphine and ketorolac. The mean difference in change in pain score in the triple therapy group and double therapy group was 7.1 cm (95% CI 6.4-7.8) and 5.9 cm (95% CI 5.1-6.7), respectively (P= 0.024). Rescue morphine was required by 7/46 (15.2% [95% CI 4.4-20.6]) patients in the triple therapy group and 14/43 (32.6% [95% CI 18.0-47.1]) in the double therapy group (OR 0.37 [95% CI 0.133-1.038]).

CONCLUSIONS

Although the addition of BB to morphine and ketorolac appeared to show a statistically significant reduction in pain compared with morphine and ketorolac alone, a reduction of 1.2 cm on VAS is unlikely to be clinically significant.

Visceral pain originating from the upper urinary tract

Pain originating from the upper urinary tract is a common problem and stone colic is one of the most intense pain conditions that can be experienced in the clinic. The pain is difficult to alleviate and often leads to medical attention. In humans, pain mechanisms of the upper urinary tract pain are still poorly understood, which often leads to a trial and error approach in clinical pain management. Pain from the upper urinary tract seems to have all the characteristics of pure visceral pain, including referred pain with or without hyperalgesia/trophic changes in somatic tissues and viscero-visceral hyperalgesia. However, further studies are needed to better understand these visceral pain mechanisms with regard to optimising pain management. This review gives an introduction to visceral pain in general and upper urinary tract pain in particular, with special reference to pain pathways and pharmacological and non-pharmacological pain modulation.

Celecoxib in the management of acute renal colic: a randomized controlled clinical trial

OBJECTIVES

To evaluate the efficacy of celecoxib as an analgesic and medical expulsive agent in acute renal colic.

METHODS

A prospective randomized double-blind study was conducted on patients presenting with an obstructing ureteral calculus < 10 mm in largest diameter. Patients were randomized to 400 mg of celecoxib, followed by 200 mg every 12 hours for 10 days, or to placebo. Patients with a solitary kidney, renal insufficiency (CR > 1.8), urinary tract infection, or significant cardiovascular disease were excluded.

RESULTS

A total of 57 patients provided consent of which 53 completed the study. Four patients were excluded from the analysis because of stone passage or withdrawal of consent before the first dose of study medication. No significant difference was noted in the spontaneous stone passage rate (celecoxib 55.2%, placebo 54.2%) and between celecoxib and placebo with regard to days to stone passage (7.0 vs 9.0, P = .6) or size of stone passed (3.9 vs 4.6 mm, P = .18). No significant difference was noted in pain analog scores (2.6 vs 3.5, P = .71) or narcotic doses (13.2 vs 13.6, P = .74). Furthermore, a 25% decrease in narcotic use (or 19 mg based on placebo mean) was outside the 80% one-sided confidence interval for the change in mean narcotic use between the 2 groups. Thus, it is unlikely (< 20%) that we missed a clinically significant beneficial effect of celecoxib on narcotic consumption because of sample size.

CONCLUSIONS

Celecoxib does not facilitate stone passage or decrease narcotic requirements in patients with acute renal colic.

Can prilocaine infiltration alone be the most minimally invasive approach in terms of anesthesia during extracorporeal shock wave lithotripsy?

OBJECTIVES

To evaluate the analgesic effect and utility of prilocaine infiltration alone for minimal morbidity during extracorporeal shock wave lithotripsy.

METHODS

A total of 114 patients with kidney stones, aged 18 to 69 years, were randomly separated into two groups. The 58 patients in group 1 received intramuscular diclophenac 30 minutes before extracorporeal shock wave lithotripsy, and the 56 patients in group 2 received prilocaine infiltration into the 30 cm2 area below the 12th rib right before the session. A visual analog scale (0 to 100 mm) was used to evaluate pain.

RESULTS

The visual analog scale scores for group 2 were statistically lower at 1, 10, and 20 minutes compared with the scores for group 1 (P = 0.006, P = 0.005, and P = 0.006, respectively). However, no difference was detected at the end of the procedure. The requirement for additional analgesic was less in group 2 (P = 0.007).

CONCLUSIONS

Prilocaine infiltration alone can be used for analgesic purposes efficiently and safely during extracorporeal shock wave lithotripsy with minimal morbidity.

Expression of Rho-kinase (ROCK-1 and ROCK-2) and its substantial role in the contractile activity of the sheep ureter

Expression of two isoforms of Rho-kinase (ROCK) and its functional role in the physiological control of smooth muscle contraction in the sheep ureter were investigated. Helical strips of the ureteric smooth muscle were stimulated by electrical field stimulation (EFS, 60 V, 1 mS, 2, 4, 8, 16 and 32 Hz, for 20 S), KCl (80 mm), carbachol (CCh, 10(-8)-10(-4) m) or phenylephrine (Phe, 10(-8)-10(-4) m). EFS produced a reproducible contractile activity, which was abolished by tetrodotoxin (3 x 10(-6) m), a Na(+) channel blocker. A muscarinic receptor antagonist, atropine (2 x 10(-6) m), and an adrenergic neuron blocker, guanethidine (10(-5) m), significantly suppressed the contraction induced by EFS. However, this contraction was augmented in the presence of N(G)-nitro-l-arginine (l-NA, 10(-4) m), a nitric oxide synthase inhibitor. Two Rho-kinase inhibitors, Y-27632 (5 x 10(-5) m) and fasudil (5 x 10(-5) m), markedly attenuated the EFS-elicited contraction. CCh and Phe produced concentration-dependent contraction in the sheep ureter. pD(2) values for Phe and CCh were 5.04+/-0.11 and 5.00+/-0.22, respectively. Y-27632 (5 x 10(-5) m) and fasudil (5 x 10(-5) m) also significantly inhibited CCh- and Phe-induced contractions. Moreover, these ROCK inhibitors produced relaxations in the KCl-elicited contraction in a concentration-dependent manner. pD(2) values for Y-27632 and fasudil were, respectively, 5.17+/-0.07 and 4.58+/-0.08 (P<0.001). Furthermore, the influences of these agents were also tested on spontaneous phasic contractions of the tissue. Among Y-27632, fasudil, TTX, l-NA, guanethidine and atropine, only the ROCK inhibitors (10(-6)-10(-5) m) were able to suppress the spontaneous contractile activity. Western blot analysis has revealed that both isoforms of Rho-kinase (ROCK-1 and ROCK-2) are expressed in the sheep ureter. Densitometric analysis has indicated that these enzymes are less expressed in the sheep ureter than are in the sheep aorta in a significant manner. These results show that a contractile enzyme, Rho-kinase, is expressed, and it mediates agonist- and EFS-induced contractions as well as spontaneous contractile activity of the isolated sheep ureter. Since Y-27632 and fasudil depressed the contractions, it seems plausible to postulate that Rho-kinase inhibitors may be beneficial in the treatment of renal colic.

Effects of tramadol on behavioural indicators of colic pain in a rat model of ureteral calculosis

This study investigated the effect of prolonged administration of tramadol vs. placebo on behavioural indicators of ureteral pain and referred lumbar muscle hyperalgesia in a rat model of artificial ureteral calculosis. Four groups of 10 rats each (female, Sprague-Dawley) were treated twice a day, for 4 days, with i.p. injections of tramadol 1.25 mg/kg, 2.5 mg/kg, 5 mg/kg or saline, respectively. The first injection was delivered 45 min before laparotomy (under pentobarbital anaesthesia) for formation of the stone in the upper left ureter via injection of dental cement. All rats were video-taped 24 h non-stop from the immediate postoperative period until the 4th day for recording of behavioural ureteral crises indicative of colic pain. Lumbar muscle sensitivity was tested daily over the same period by verifying presence or absence of vocalization upon pinching of the parietal layers at L1 level, bilaterally, at a constant predefined pressure value with calibrated forceps. Tramadol significantly reduced number and global duration (ANOVA, P < 0.008 and P < 0.004) of ureteral crises with respect to saline and the effect was dose-dependent (linear regression analysis between doses and parameters of crises, P < 0.003 and P < 0.002). The drug also significantly reduced the incidence of referred muscle hyperalgesia (ANOVA, P < 0.0001). It is concluded that tramadol is highly effective in controlling pain phenomena from urinary stones and can represent a valid therapeutic approach in patients with urinary colics.

Sublingual hyoscyamine sulfate in combination with ketorolac tromethamine for ureteral colic: a randomized, double-blind, controlled trial

STUDY OBJECTIVE

We evaluate the safety and efficacy of a single dose of hyoscyamine sulfate in combination with ketorolac tromethamine for the reduction of pain in emergency department patients with ureteral colic.

METHODS

We conducted a prospective, randomized, double-blind study at 2 EDs with residency programs in emergency medicine. Patients were at least 18 years old and presented to the ED with an initial history and physical examination consistent with ureteral colic. Patients received a single intravenous dose of 30 mg of ketorolac tromethamine given over a 1-minute period with either a single sublingual dose of 0.125 mg of hyoscyamine sulfate or a placebo. If inadequate analgesia was noted after 30 minutes, a standard dose of meperidine could be administered for rescue. All other treatments including intravenous fluids and antiemetics were standardized. The main study outcome was change in visual analog scale pain score from baseline to 30 minutes.

RESULTS

Seventy-two patients were evaluated for inclusion. Thirteen patients who had self-administered pain medications within 4 hours of presentation were excluded before randomization. Sixteen patients who did not have a renal calculus confirmed by either intravenous urogram or helical computed tomography were also excluded from efficacy analysis. There did not appear to be any clinically important differences in the baseline characteristics between the 2 groups. The repeated-measures analysis of the remaining 43 patients showed no clinically important difference in pain score using the visual analog scale at any time point. There were no clinically important differences between the 2 study groups for amount of rescue meperidine administered or end-of-study global satisfaction scores.

CONCLUSION

Hyoscyamine sulfate did not provide any additional pain relief from ureteral colic when administered with ketorolac tromethamine. There was no clinically important difference in change of pain scores at 30 minutes in patients with ureteral colic receiving supplemental hyoscyamine sulfate.

Pre-emptive analgesia in rats with artificial ureteric calculosis. Effects on visceral pain behavior in the post-operative period

'Pre-emptive' analgesia is a controversial issue in both the clinical and experimental literature on pain. This paper investigates the effect of chronic (4 days) administration of morphine or ketoprofen initiated pre- or post-operatively on behavioral indicators of visceral pain and referred hyperalgesia in an animal model of artificial ureteric calculosis. In the morphine experiment, female Sprague-Dawley rats were treated i.p. with saline or morphine sulphate (2.5 or 5 mg/kg/day) starting either 45 min before or 45 min after surgery (pentobarbital anesthesia) for stone implantation in the left ureter, until the 4th day after intervention. Behavioral crises of ureteric pain were recorded (video-tape) in all rats over 4 days post-operatively. Number, duration and complexity of crises of stone-rats were significantly and dose-dependently reduced by administration of morphine with respect to saline in an identical manner for the pre- and post-operative treatment. In the ketoprofen experiment, rats were given saline or ketoprofen (15 mg/kg/day, in 3 i.p. injections per day) starting either pre- or post-operatively with the same paradigm as for the morphine study. Vocalization thresholds to electrical stimulation of the left oblique musculature were measured daily for 3 days pre- and 4 days post-operatively. Muscle hyperalgesia (post-operative decrease in threshold with respect to pre-stone implantation) was significantly reduced in extent and duration in ketoprofen with respect to saline-injected animals but no difference was found between the pre- and post-operative treatment. It is concluded that pre-emptive administration of morphine or ketoprofen has no advantage in reducing behavioral indicators of visceral pain and referred hyperalgesia in this animal model.