Which of the following medication is used to directly relax the lower esophageal sphincter?
Commonly used medications to relax the lower esophageal sphincter in patients with achalasia include nitrates such as isosorbide dinitrate (remember that nitric oxide physiologically inhibits the lower esophageal sphincter) and calcium channel blockers such as nifedipine (which inhibit calcium flow into the smooth muscle of the lower esophageal sphincter, thereby inhibiting contraction.) For patients in whom medical therapy fails, other options include paralysis of the lower esophageal sphincter with intrasphincteric injection of botulinum toxin, pneumatic dilatation, and a Heller myotomy (which interrupts the muscles of the lower esophageal sphincter). Also know: Diphenoxylate is an opiate antidiarrheal, and would not be useful for achalasia. Famotidine is an H2 antagonist that would be useful in reducing stomach acidity, but would not directly affect lower esophageal pressure. Other drugs in this class include cimetidine, ranitidine, and nizatidine. Granisetron is a 5HT3 antagonist and is used to prevent nausea and vomiting in patients who receive chemotherapy, and after general anesthesia. Other members of this drug class include ondansetron and dolasetron. Ref: Michel T., Hoffman B.B. (2011). Chapter 27. Treatment of Myocardial Ischemia and Hypeension. In L.L. Brunton, B.A. Chabner, B.C. Knollmann (Eds), Goodman & Gilman's The Pharmacological Basis of Therapeutics, 12e.
Diphenoxylate
Famotidine
Granisetron
Isosorbide dinitrate