Table 3.

Drugs used in the treatment of CID.

	Mechanism	Side effects
Loperamide	Loperamide is a peripherally restricted mu opioid receptor agonist that decreases secretion and intestinal motility by decreasing excitability of enteric neurons (Brunton et al., 2017; Wadler et al., 1998)	Constipation, nausea, vomiting, cardiovascular effects
Deodorized tincture of opium	Centrally active mu-opioid receptor agonist inhibits gastrointestinal motility (Gershon et al., 1994)	CNS effects, tolerance
Octreotide	Somatostatin analogue that decreases hormone secretion (e.g., vasoactive intestinal polypeptide), reduces motility and pancreatic secretions and promotes absorption (Brunton et al., 2017; Deng et al., 2017; Zidan et al., 2001)	Nausea, bloating, hypo or hyperglycemia, gallstone formation, endocrine, cardiovascular and CNS side effects
Budesonide	Topically active corticosteroid that might restore mucosal function and fluid absorption; a 90% first-pass effect in the liver results in low systemic availability (Brunton et al., 2017; de Man et al., 2018; Ribeiro et al., 2016)	Endocrine effects
Atropine	Inhibition of acetylcholine at muscarinic receptors located at neuromuscular junction to inhibit motility (Brunton et al., 2017; Stein et al., 2010)	Cognitive impairment, xerostomia, constipation, blurred vision, dyspepsia
Antibiotics	Broad spectrum antibiotic that targets small intestinal bacterial overgrowth (Boussios et al., 2012; Brunton et al., 2017)	Diarrhea, increased risk of C. difficile infection
Bile acid sequestrants	Prevent water secretion into the colon induced by non-sequestered bile acids (Brunton et al., 2017)
Beta-glucuronidase inhibitors	Inhibits removal of glucuronic acid moiety by gut commensal bacteria (Bhatt et al., 2020)