Advances in Management of Large Intestinal Colic

1. Spasmodic (Gas) Colic
Spasmodic colic is the result of increased peristaltic contractions in the horse’s gastrointestinal tract and is thought to be one of the most common causes of colic.1 It can be the result of a mild gas buildup within the horse’s digestive tract. The signs of colic are generally mild and respond well to spasmolytic and analgesic medication, and diagnosis is often made based on response to treatment. A novel therapeutic, n-butylscopolammonium bromide^a  , has recently become available in North America for the treatment of spasmodic colic. N-butylscopolammonium bromide is an antispasmodic and anticholinergic drug for IV use in horses. It is labeled for the control of abdominal pain associated with spasmodic colic, flatulent colic, and simple impactions in horses. This drug is an anticholinergic, causing competitive inhibition of parasympathetic activation (through muscarinic receptors) of smooth muscle cells.²  As a result, n-butylscopolammonium bromide impedes peristalsis and reduces the abdominal discomfort associated with abnormal gastrointestinal motility.²  In addition, n-butylscopolammonium bromide reduces rectal pressure and facilitates rectal examinations in horses. The major side effects of this drug are a transient tachycardia and decreased boborygmal sounds. Transient pupillary dilation has also been reported.^2,3  The decreased boborygmal sounds are reported to last ~30 min after administration.^2,3  Because of the effect of n-butylscopolammonium bromide on peristalsis, multiple dosing should be avoided, and repeated use in impaction colic is contraindicated. [...]