Gastrointestinal agents

Question 1

dicyclomine HCl

Answer 1

Brand - Bentyl

Class - Antimuscarinic

Indication - IBS-(D/M/U)

Contraindications - <6mo, breastfreeding, GI obstruction, glaucoma, myasthenia gravis, obstructive uropathy, reflux esophagitis, severe ulcerative colitis, toxic megacolon, unstable CV state in acute hemorrhage

Counseling - Decreases sweating, may overheat in hot environ; may cause drowsiness, caution driving

MoA - Relieves smooth muscle spasm of GI tract via anticholinergic effect at the ACh sites and directly on smooth muscle (antimuscarinic/musculotropic)

Question 2

docusate Na+

Answer 2

Brand - Colase

Class - Stool Softener (emollient laxative)

Indication - Constipation (preventative)

Contraindication: Intestinal obstruction, acute abdominal pain, nausea, vomiting, use of mineral oil

Counseling - Work within 1 to 2 days, up to 3 to 5, do not take longer unless instructed, maintain hydration

MoA - Surfactant draws water and increases fat penetration into the stool to prevent straining during bowel movement

Question 3

esomeprazole

Answer 3

Brand - Nexium

Class - Proton Pump Inhibitor

Indication - H. pylori infection (w/ amox&clarith), erosive esophagitis (GERD/kid heartburn), NSAID gastropathy prevent, Zollinger-Ellison synd

Counseling - Tk 1h before meals

MoA - PPI covalently binds to proton pump for prolonged antisecretory effect of gastric acid secretion (basal, nocturnal, pentagastrin-stimulated, and food-stimulated)

Question 4

famotidine

Answer 4

Brand - Pepcid

Class - Histamine H2 antagonist

Indication - Duodenal/gastric ulcer, GERD, indigestion

Counseling - Tk at bedtime. May tk w/ food/antacids if needed; shake well if suspension

MoA - Competitive inhibitor of H2, inhibits gastric secretion, both in acid concentration and volume

Question 5

lansoprazole

Answer 5

Brand - Prevacid

Class - Proton Pump Inhibitor

Indication - Duodenal/gastric ulcer, H. pylori infect (w/ amox&clarith), erosive esophagitis/GERD, Zollinger-Ellison syndr

Counseling - Tk on empty stomach 1 h before eating, separate from antacids; more effective if taken regularly than prn, may swallow on applesauce if needed.

MoA - PPI protonated in parietal cells to covalently bind to proton pump that secretes acid

Question 6

meclizine HCl

Answer 6

Brand - Antivert, Dramamine, Bonine

Class - Antiemetic (antihistamine)

Indication - Motion sickness, Vertigo

Counseling - May cause drowsiness, avoid alcohol & CNS depressants, tk w/ food if GI upset; caution in patients w/ asthma, glaucoma, enlarged prostate (anti-ACl effect)

MoA - Anti-H suppresses the vasodepressor response to H (only slightly inhibiting ACl)

Question 7

omeprazole

Answer 7

Brand - Prilosec

Class - Proton Pump Inhibitor

Indication - Duodenal/gastric ulcer, H. pylori infect (w/ amox&clarith), erosive esophagitis/GERD

Counseling - Tk 1 h before meals

MoA - PPI covalently binds to proton pump for prolonged antisecretory effect of gastric acid secretion (basal, nocturnal, pentagastrin-stimulated, and food-stimulated)

Question 8

ondansetron

Answer 8

Brand - Zofran

Class - Antiemetic

Indication - Nausea & vomiting (chemotherapy, postoperative, or radiation-induced)

Contraindications - Concomitant apomorphine or drugs that increase QTc interval

Pregnancy - Risk

Counseling - Gentle open blister pack w/ dry hands, dissolve tab on tongue (water not required)

MoA - Selective 5-HT3 antagonist (present in the chemoreceptor trigger zone) - chemo releases 5-HT from the small intestine initiating this reflex

Question 9

pantoprazole Na+

Answer 9

Brand - Protonix

Class - Proton Pump Inhibitor

Indication - Erosive esophagitis/GERD, gastric hypersecretion, Zollinger-Ellison syndr

Counseling - Best taken before meals; seek medical care for severe headache/blistering skin rash

MoA - PPI covalently binds to proton pump for prolonged antisecretory effect of gastric acid secretion (basal, nocturnal, pentagastrin-stimulated, and food-stimulated)

Question 10

polyethylene glycol

Answer 10

Brand - CoLyte, Golytely, MoviPrep

Class - Hyperosmotic Laxative

Indication - Colonoscopy/barium enema prep, constipation

Contraindications - Bowel perforation, GI obstruction/gastric retention, ileus, toxic megacolon

Counseling - Completely dissolve powder; may cause nausea, anal irritation, vomiting. Slow consumption if abdominal bloating/distension/pain occurs. If for bowel imaging study, avoid solid foods 3-4h before this treatment

MoA - PEG electrolyte solution is hyperosmotic that induces catharsis by osmotic effects of unabsorbed salts

Question 11

sucralfate

Answer 11

Brand - Carafate

Class - Misc GI agent

Indication - Duodenal ulcer

Counseling - Tk on empty stomach, no other meds within 2-4 h. Shake suspension well, store at room temp.

MoA - Forms a complex w/ +++proteins that forms a protective coating for local protection of the gastric lining against peptic acid/pepsin and bile salts