Chapter 16 - Gastrointestinal Drugs

Question 1

Antacids

P. 260

Answer 1

Act by partially neutralizing gastric hydrochloric acid and are widely available in many over-the-counter (OTC) preparations for the relief of indigestion, heartburn, and sour stomach.

Question 2

Antiulcer

P. 260 and 584

Answer 2

Drug that reduces gastric acid secretion or that acts to prevent or treat gastric or duodenal ulcers.

Question 3

Histamine 2 Blockers

P. 261 and 589

Answer 3

Agent that blocks the histamine receptors found in the stomach to reduce gastric acid secretion.

Question 4

Gastroesophageal reflux disease (GERD)

P. 261 and 588

Answer 4

A backward flow of gastric secretions into the esophagus causing inflammation and discomfort. GERD is treated with drugs to accelerate gastric emptying.

• cimetidine, famotidine (Pepcid), and ranitidine (Zantac), are used short term for the relief of “acid indigestion and heartburn”, GERD, esophagitis, and prevention of duodenal ulcer recurrence.

Question 5

Omeprazole (Prilosec)

P. 262

Answer 5

Is a gastric antisecretory agent (proton pump Inhibitor or PPI) used short term.

Question 6

Helicobacter pylori

P. 264

Answer 6

Bacterial infection plays a major role in the development of gastritis, gastric and duodenal ulcer racing, and gastric cancer.

Question 7

Antispasmodics

P. 266

Answer 7

or anticholinergics how to calm the bowel.

• (e.g. Dicyclomine (Bentyl), is an anticholinergic and antimuscarinic agent used for the treatment of irritable bowel syndrome and other functional disturbances of GI motility.

Question 8

Inflammatory bowel disease (IBD)

P. 266

Answer 8

Is a chronic condition that causes inflammation in the lining of the GI tract and include Crohn’s disease and ulcerative colitis.

Question 9

Antidiarrheal agents

P. 267

Answer 9

Act in various ways to reduce the number of loose stools.

Question 10

Bismuth subsalicylate (e.g. Kaopectate, Pepto-Bismol)

P. 268

Answer 10

Has anti-infective and antisecretory properties, a direct mucosal protective effect, and weak antacid and anti-inflammatory effects.

• a side effect: discoloration of tongue and stool (black color).

Question 11

Probiotics

P. 269

Answer 11

Are living microorganisms that can alter a patient’s intestinal flora and may provide benefit in numerous GI diseases.

Question 12

Lactobacillus acidophilus

P. 269

Answer 12

Is an acid producing probiotic bacterium, available in several forms over the counter. It is administered orally for the treatment of simple uncomplicated diarrhea caused by antibiotics, infection, irritable colon, colostomy, or amebiasis.

• Lactobacillus bacteria help to re-establish normal intestinal Flora.

Question 13

Saccharomyces boulardii (Florastor)

P. 269

Answer 13

Is a yeast used in dairy fermentation. It is a probiotic often started within 3 days of antibiotic initiation and continued for three days after discontinuation to prevent diarrhea.

• probiotic bacteria are also found in yogurt Activia and other dairy foods for the replacement of beneficial intestinal tract bacteria.

Question 14

Clostridium difficile (C. diff)

P. 270 and 586

Answer 14

Species of bacteria that cause pseudomembranous colitis.

• Symptoms of C. difficile diarrhea (CDD) may include watery diarrhea, nausea, and/or abdominal pain or tenderness.
• complications may include sepsis, renal failure, toxic colitis, and death. CDD is caused primarily by the eradication of the Native intestinal Flora with broad-spectrum antimicrobial and overuse of PPI and H2-blocker therapy.
• oral medications include metronidazole (Flagyl) or vancomycin.
• is one of the most common causes of infectious diarrhea in the US.

Question 15

Antiflatulents

P. 270

Answer 15

(e.g. simethicone) are used in the symptomatic treatment of gastric bloating and post-operative gas pains, by helping to break up gas bubbles in the GI tract.

Question 16

Laxatives

P. 271

Answer 16

Promote evacuation of the intestine and are used to treat constipation.

• Laxatives can be subdivided into 7 categories according to their action: bulk-forming laxatives, stool softeners, emollients, saline laxatives, stimulant laxatives, osmotic laxatives, and chloride channel activator.

☆ When constipation occurs, the cause should be identified before a laxative are used.

Question 17

Stool softeners

P. 272

Answer 17

(e.g., docusate) are surface acting agents that moisten stool through a detergent action and are administered orally. The onset of action is usually 12 to 72 hours.

Question 18

Emollients

P. 273

Answer 18

Promote stool movement through the intestines by softening and coating the stool.

• mineral oil may be administered orally and is usually effective in 6 to 8 hours. Mineral oil and sometimes administered rectally as an oil retention enema (60-120mL).

Question 19

Saline laxatives

P. 273

Answer 19

(e.g., milk of magnesia (MOM) or citrate of magnesia) promote secretion of water into the intestinal Lumen and should be taken only infrequently in single. The onset of action is 0.5-3 hours.

Question 20

Stimulant laxatives

P. 274

Answer 20

(e.g., senna, castor oil, and bisacodyl) are cathartic in action, producing strong peristaltic activity, and may also alter intestinal secretions in several ways. The onset of action is 0.25-8 hours, depending on the preparation.

• are habit-forming, and long-term use may result in laxative dependence and the loss of normal bowel function.

Question 21

Osmotic laxatives

P. 275

Answer 21

Such as glycerin, lactulose, polyethylene glycol (PEG), and sorbitol exert in action that draws water from the tissues into the feces and reflexively stimulates evacuation.

• onset of action for glycerin is within 15 to 60 minutes.
• onset of action for lactulose is within 24 to 48 hours.
• onset of action for polyethylene glycol (Miralax) can be seen in 0.5-3 hours.

Question 22

Chloride Channel activators

P. 275

Answer 22

Lubiprostone (Amitiza) is a unique oral agent for the treatment of constipation. It increases intestinal fluid secretion by activating specific chloride channels in the intestinal epithelium. Most patients experience a bowel movement within 24 hours of the first dose.

Question 23

Peripherally Acting Mu-opioid Receptor Antagonists

P. 275

Answer 23

Naloxegol (Movantik) is a new oral agent specifically designed for the treatment of constipation caused by chronic or acute opioid use.

Question 23

Peripherally Acting Mu-opioid Receptor Antagonists

P. 275

Answer 23

Naloxegol (Movantik) is a new oral agent specifically designed for the treatment of constipation caused by chronic or acute opioid use.

Question 24

Antiemetics

P. 277

Answer 24

Are used in the prevention or treatment of nausea, vomiting, vertigo, or motion sickness.

Question 25

Anticholinergics

P. 277

Answer 25

Drugs that block the action of the parasympathetic nervous system.

• motion sickness.

Question 26

Motion sickness

P. 277

Answer 26

Is mediated by the cholinergic and histaminic receptors in the inner ear.

• For prophylaxis of motion sickness, anticholinergic drugs such as dimenhydrinate (Dramamine) or scopolamine are used.
• For greatest Effectiveness, the Transderm-scop patch is applied behind the ear four hours before anticipated exposure to motion (DO NOT cut patch) and is effective up to 72 hours.

Question 27

Dramamine

P. 277

Answer 27

(For motion sickness); Is administered orally 30 minutes before exposure to motion.

Question 28

Meclizine (Antivert)

P. 277

Answer 28

Is in antihistamine used in the prevention and treatment of nausea, vomiting, and or vertigo associated with motion sickness, and in the symptomatic treatment of vertigo associated with the vestibular system (e.g., Meniere’s disease).

Question 29

Serotonin-receptor Antagonists: ondansetron (Zolfran) and dolasetron (Anzemet)

(P. 278)

Answer 29

Are used for the prevention and treatment of post-operative nausea and vomiting (PONV) and for the control of chemotherapy-induced nausea and vomiting (CINV).

• Some of the side effects is sedation, drowsiness, vertigo, weakness, and headache