Effects of an Intestinal Smooth Muscle Calcium Channel Blocker (Pinaverium Bromide) on Colonie Transit Time in Humans

Improvement of Quality of Nonanesthetic Colonoscopy by Preoperative Administration of Pinaverium Bromide

Background:

Nonanesthetic colonoscopy is popular in clinical practice in China. However, intestinal spasms often result in a prolonged examination time, increased operating difficulties, decreased polyp detection rate, and failure to complete the procedure clinically. Therefore, exploring alternative approaches that can reduce the pain in patients during colonoscopy is of utmost importance, and finding the optimal preoperative administration to improve the quality of nonanesthetic colonoscopy is also necessary. This study aimed to investigate the effects of the prophylactic administration of pinaverium bromide before colonoscopy and the effects of pinaverium bromide alone at different time points or combined with scopolamine butylbromide.

Methods:

A randomized controlled trial was performed on a cohort of 1000 patients who underwent colonoscopy in outpatient clinic of Wuhan Union Hospital. The patients were randomly assigned to the following groups: Group A, given oral pinaverium bromide (100 mg, three times a day) one day before examination combined with intramuscular injection of scopolamine butylbromide (20 mg) 10 min before colonoscopy; Group B₀, given pinaverium bromide alone on the day of colonoscopy (100 mg, three times a day); Group B₁, given pinaverium bromide alone (100 mg, three times a day) one day before colonoscopy; Group B₂, given pinaverium bromide alone (100 mg, three times a day) two days before colonoscopy; and Group C, given scopolamine butylbromide alone (20 mg) before colonoscopy. The successful rate of colonoscopy, procedure time, degree of abdominal pain, and polyp detection rate were recorded and compared among all groups.

Results:

The successful rate of colonoscopy in Group B₁ (82.0%) and Group B₂ (83.0%) was significantly higher than that in Group B₀ (62.0%, all P < 0.01). The time to reach the ileocecal region in Group B₁ and Group B₂ were lower than those in Group B₀ (all P < 0.05). However, no significant differences were observed in polyp detection rate between Group B₁ (24.0%) or Group B₂ (26.0%), and Group B₀ (22.4%, all P > 0.05). Furthermore, there were no significant differences in the various parameters examined between Group B₁ and Group B₂ (P > 0.05). The successful rate of colonoscopy in Group A (92.0%) was significantly higher than that in Group B₁ (82.0%) and Group C (80.0%; both P < 0.05). Moreover, the time for the colonoscope to reach the ileocecal region in Group A were markedly shorter as compared to those in Group B₁ and Group C (P < 0.05). The polyp detection rate in Group A was 32.0%, significantly higher than that in Group B₁ (24.0%, P < 0.05) and Group C (24.2%, P < 0.05).

Conclusion:

Administration of pinaverium bromide alone one day before examination was beneficial to relieve symptoms of abdominal pain during nonanesthetic colonoscopy. In addition, therapeutic effects were improved when pinaverium bromide administration was combined with intramuscular injection of scopolamine butylbromide. Therefore, the combined use of pinaverium bromide with scopolamine butylbromide might have great application value to improve the quality of nonanesthetic colonoscopy in the preoperative preparation.

Effects of oral pinaverium bromide on colonic response to food in irritable bowel syndrome patients

We have recently developed a simple method to investigate the colonic response to food (CRF). This study describes the modifications of CRF induced by treatment with oral pinaverium bromide in irritable bowel syndrome (IBS) patients. Thirty healthy subjects and 43 patients suffering from IBS were studied. Colonic transit time (CTT) was measured in fasting conditions and after eating a standard test meal. Colonic response to food was quantified by calculating the variation in number of markers in each zone of interest of the large bowel between the X-ray films of the abdomen taken before and after eating. CRF is characterized by caudal propulsion of colonic contents in the two groups. In controls, there is emptying of the caecum-ascending colon region and filling of the rectosigmoid. In IBS patients, only the left transverse colon and the splenic flexure empty. Pinaverium bromide exerts no effect in controls but reverses the CRF of the right colon in IBS patients by inhibiting right colon emptying. These results suggest that the inhibitory action of pinaverium bromide on CRF may support the clinical efficacy of this calcium channel blocker in the treatment of IBS.

Functional gut disorders: from motility to sensitivity disorders. A review of current and investigational drugs for their management

Functional gut disorders include several clinical entities defined on the basis of symptom patterns (e.g., functional dyspepsia, irritable bowel syndrome, functional abdominal pain, functional abdominal bloating), for which there is no established pathophysiological mechanism. Because there is no well-defined pathophysiological target, treatment should be aimed at symptom improvement. Prokinetics and antispasmodics have been widely used in the treatment of functional gut disorders on the assumption that disordered motility is the underlying cause of symptoms, and symptom improvement is indeed achievable with these compounds in some, but not all, patients with features of hypo- or hypermotility, respectively. In the first part of this review, we cover the basic pharmacology and discuss the rationale for the clinical use of prokinetics and antispasmodics. On the other hand, in the past few years, the explosive growth in the research focusing on visceral sensitivity and visceral reflexes has suggested that at least some patients with functional gut disorders have altered visceral perception. Thus, the second part of the review covers these developments and focuses on studies addressing the issue of drugs modulating visceral sensitivity.

Constipation and megacolon in rats related to treatment with oxodipine, a calcium antagonist

The constipatory effects of oxodipine, a dihyrdopyridine-type calcium antagonist, have been described in a 3-mo, 12-mo, and 30-mo feeding toxicity study in rats. This paper reports the occurrence of megacolon in rats as a result of the constipatory effects of chronic administration of oxodipine. The first mortality due to oxodipine was seen after about 1 yr of treatment at a dose of 225 mg/kg/day. The toxic effects noted were dose-, time-, and sex-related. Female rats appeared more sensitive to the constipatory effects of the drug. The dose at which the effect occurred in both male and female rats was from about 75 to 675 times the recommended therapeutic dose for humans. To the best knowledge of the authors, this is the first report of a calcium channel blocker causing constipation in rats.

Calcium-channel blockers and gastrointestinal motility: basic and clinical aspects

Several calcium-channel blockers currently in use for the treatment of cardiovascular disorders have recently been tested for their effects on gastrointestinal motility. The rationale for this approach centers on the concept that calcium-channel blockers are at least as potent in inhibiting intestinal smooth muscle as in relaxing vascular smooth muscle. This review will give an outline of the most recent findings on the role of calcium and calcium channels in smooth muscle and neuronal function in the digestive system. It will also consider the mechanisms by which calcium-channel blockers may affect gastrointestinal motility and assess potential clinical applications in gastroenterology. The main goal for researchers in this field will be the development of gut-selective agents, with no cardiovascular side effects.

Effect of verapamil on human intestinal transit

Although constipation is a well-known side effect of calcium channel blockers such as verapamil, this side effect has not been evaluated in a quantitative manner. In a double-blind, randomized, crossover trial, the effect of verapamil (240 mg/day) was compared to placebo in 15 normal male volunteers. Subjects recorded their bowel movements and any side effects. Scintigraphy was used to quantitate gastric emptying, small intestinal transit, and colonic transit. In the study period of four days, verapamil did not change the frequency, consistency, or passage of bowel movements. A significantly increased number of side effects was noted during verapamil treatment--notably abdominal pain and dry mouth. The slope of gastric emptying was not significantly different for verapamil (0.012 +/- 0.02) than for placebo (0.013 +/- 0.001). Distal ileum filling was also not different for verapamil (0.41 +/- 0.13%/min) than placebo (0.33 +/- 0.05%/min). Progression of the colonic geometric center was significantly delayed at 48 hr by verapamil (5.2 +/- 0.4 vs 6.2 +/- 0.23; P less than 0.01). This study suggests that the constipating effect of verapamil is due to a delay of colonic transit and not due to an effect on upper gastrointestinal transit.

Effect of pinaverium bromide on jejunal motility and colonic transit time in healthy humans

Pinaverium bromide is a specific calcium channel blocker used in the treatment of irritable bowel syndrome (IBS) for its spasmolytic activity. The aim of the present study was to evaluate the effect of orally administered pinaverium bromide on jejunal motility and total and segmental colonic transit time in control subjects. Gastrointestinal studies were performed in 10 healthy volunteers (30 +/- 3 years), before and after a treatment phase of 14 days (150 mg/d). Jejunal motility was measured by prolonged manometry (14 h) and colonic transit time by a multiple ingestion, single marker technique. No significant modification of phase III of the migrating motor complexes was demonstrated. On the contrary, a significant (p < 0.01) but weak decrease of the frequency of contraction was found. Unlike previous studies, no decrease of total or segmental colonic transit time was demonstrated.