Effect of verapamil on human intestinal transit

Abstract

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.

Mild dehydration: a risk factor of constipation?

“…A delay in transit time in the colon may permit increased local fluid absorption of intestinal contents due to the extended mucosal contact duration. Constipation was not explained by dehydration, as water was available at any time throughout the study periods (Krevsky et al, 1992).…”

Constipation and Megacolon in Rats Related to Treatment with Oxodipine, a Calcium Antagonist

“…In humans, verapamil induces constipation due to delayed colonic transit without any effect on gastric emptying or distal ileal filling (11). The mechanism by which oxodipine caused its constipatory effect on the colon was not investigated; however, it is clear that a delay in transit time in the colon would permit increased local fluid absorption of intestinal contents due to the extended mucosal contact duration.…”

“…Calcium channel blockers have recently been added to the list of compounds that can cause constipation. Verapamil (11), nifedipine (14,16), and diltiazem (12) have been documented as causing constipation in humans, although in a small percentage of patients. Of these drugs, only verap-amil has been studied in relation to its effect on the human colon (11).…”

Gastrointestinal Motility, Part 2: Small-Bowel and Colon Transit

“…When measured using resin pellets mixed with a meal, orocecal transit time in healthy individuals ranged from 151 to 290 min (18). When measured using the liquid phase of a mixed solid-liquid meal, small-bowel transit time ranged from 72 to 392 min in healthy individuals (15).…”

“…This region is also referred to as the ileocolonic junction (16,17). The progressive buildup of activity in the terminal ileum can easily be measured and used as an index of small-bowel motility (18). The recent SNMMI/EANM guideline on small-bowel transit recommends use of the percentage of administered liquid meal that has accumulated in the terminal ileum at 6 h after meal ingestion as a simple index of small-bowel transit.…”