Esophageal obstruction, or "choke," is a common occurrence in horses that veterinarians approach with a number of treatments from passing a nasogastric tube to sedation and other drug approaches. At the 2011 American Association of Equine Practitioners convention, held Nov. 18-22 in San Antonio, Texas, Joe Bertone, DVM, MS, Dipl. ACVIM, presented information about the use of the antispasmodic N-butylscopolammonium bromide (Buscopan)—a drug generally used in colic cases—as an effective treatment to relieve simple choke.
Bertone explained that Buscopan is known for its ability to relax smooth muscle and is useful in managing and diagnosing abdominal pain (colic). Veterinarians often use the drug to reduce the risk of rectal tear during palpation and when performing a variety of obstetrical procedures including twin reduction and dystocia (difficult birth) management. Anecdotally, Buscopan has been reported effective in relieving meconium (the first manure a foal produces) and ileal impactions, he said.
Buscopan has been accepted as effective treatment for simple choke in other countries for 40 years, Bertone noted, but interestingly, the drug was not designed to have an effect on the proximal (upper) skeletal muscle esophagus from the back of the mouth, along the neck, and to the heart ("This is the area where most chokes occur," he added). Rather, he said, Buscopan is designed to relax the smooth muscle of the distal (lower) third of the esophagus (from the heart to the stomach).
"The proximal area is where choke (typically) occurs, yet the drug exert