DRUGS STIMULATING MOTILITY •MetoclopramideD2-receptorblocker•removesinhibition of acetylcholine neurons in enteric nervous system Increases gastric emptying and intestinal motility Gastric paresis (eg, in diabetes)•antiemetic(see below) Parkinsonian symptoms due to block of central nervous system (CNS) D2 receptors hydroxide, other nonabsorbable salts and sugars Osmotic agents increase water content of stool
Usually causes evacuation within 4–6 h, sooner in large doses Simple constipation;
Bulk-forming laxatives: Methylcellulose, psyllium, etc: increase volume of colon contents, stimulate evacuation
Stimulants: senna, cascara; stimulate activity; may cause cramping
Stool surfactants: Docusate, mineral oil; lubricate stool, ease passage
Chloride channel activators: Lubiprostone, prostanoic acid derivative, stimulates chloride secretion into intestine, increasing fluid content; linaclotide, guanylyl cyclase-C agonist, stimulates chloride secretion by CFTR
Opioid receptor antagonists: Alvimopan, methylnaltrexone; block intestinal μ-opioid receptors but do not enter CNS, so analgesia is maintained
Colloidal bismuth compounds: Subsalicylate and citrate salts available. OTC preparations popular and have some value in travelers’ diarrhea due to adsorption of toxins
Kaolin + pectin: Adsorbent compounds available OTC in some countries
Anticholinergics: Nonselective action on gut activity, usually associated with typical antimuscarinic toxicity
Chloride channel activator: Lubiprostone (see above); useful in constipation-predominant IBS in women; linaclotide (see above): useful in adults with constipation-predominant IBS
Corticosteroids: Mechanism not known but useful in antiemetic IV cocktails
Antimuscarinics (scopolamine): Effective in emesis due to motion sickness; not other types
Antihistaminics: Moderate efficacy in motion sickness and chemotherapy-induced emesis
Phenothiazines: Act primarily through block of D2 and muscarinic receptors
Cannabinoids: Dronabinol is available for use in chemotherapy-induced nausea and vomiting, but is associated with CNS marijuana effects • Corticosteroids: Generalized anti-inflammatory effect; see Chapter 39
PANCREATIC SUPPLEMENTS •PancrelipaseReplacement enzymes from animal pancreatic extracts Improves digestion of dietary fat, protein, and carbohydrate Pancreatic insufficiency due to cystic fibrosis, pancreatitis, pancreatectomy Takenwitheverymeal•mayincreaseincidence of gout •Pancreatin: Similar pancreatic extracts but much lower potency; rarely used
Aluminum hydroxide gel * Generic, AlternaGEL, others
Calcium carbonate*Generic, Tums, others
Famotidine Generic, Maalox, Mylanta, Gaviscon, Gelusil, others
Generic, Pepcid, Pepcid AC, * Pepcid Complete *
Nizatidine Generic, Axid, Axid AR*
Ranitidine Generic, Zantac, Zantac 75 *
Dicyclomine Generic, Bentyl, others
Glycopyrrolate Generic, Robinul
Hyoscyamine Anaspaz, Levsin, others
Scopolamine Generic, Transderm Scop
Omeprazole Generic, Prilosec, Prilosec OTC*
Lansoprazole Generic, Prevacid *
Pantoprazole Generic, Protonix
Granisetron Generic, Kytril
Ondansetron Generic, Zofran
Dronabinol Generic, Marinol
Fosaprepitant Emend, Emend IV