Gastrointestinal Agents

Question 1

What is the common brand name(s) for:

bisacodyl

(BIS-a-koe-dil)

Answer 1

Dulcolax

Class: Stimulant laxative

Indication: Acute and chronic constipation; bowel preparation

MOA: Directly stimulates enteric nerves in the colon, increasing peristalsis and promoting water and electrolyte secretion.

Side effects: abdominal cramps; diarrhea; electrolyte imbalances

Contraindications: Bowel obstruction; acute surgical abdomen; peritonitis

Considerations:

• Available as oral tablets and rectal suppositories.
• Recommended for short-term relief of constipation.

Question 2

What is the common brand name(s) for:

cimetidine

(sye-MET-i-deen)

Answer 2

Tagamet

Class: H₂ (histamine-2) receptor antagonist

Indication: GERD; duodenal and gastric ulcers; Zollinger-Ellison syndrome; stress-related mucosal damage prevention; adjunct in H. pylori eradication

MOA: Competitively inhibits histamine at H₂ receptors on stomach parietal cells, decreasing acid secretion.

Side effects: headache; dizziness; confusion; diarrhea; constipation; gynecomastia

Contraindications: Hypersensitivity to drug or components

Considerations:

• Contraindicated for OTC use with swallowing pain, bloody vomiting, or black stools.
• Taken before meals.
• Consider alternative H₂ blockers or PPIs if patient has many medications due to interactions.

Question 3

What is the common brand name(s) for:

darifenacin

(dar-i-FEN-a-sin)

Answer 3

Enablex

Class: Antimuscarinic agent (anticholinergic)

Indication: Overactive bladder (OAB)

MOA: Selectively blocks M3 muscarinic receptors in the bladder, reducing involuntary contractions.

Side effects: dry mouth; constipation; blurred vision; dizziness

Contraindications: Urinary retention; gastrointestinal motility disorders; narrow-angle glaucoma

Considerations:

• Administered once daily.
• Use caution in older adults due to anticholinergic effects.

Question 4

What is the common brand name(s) for:

dexlansoprazole

(dex-LAN-soe-pra-zole)

Answer 4

Dexilant

Class: Proton pump inhibitor (PPI)

Indication: GERD

MOA: Binds to and irreversibly inhibits the H⁺/K⁺-ATPase (proton pump) in stomach parietal cells, reducing acid secretion.

Side effects: diarrhea; abdominal pain; nausea; headache; risk of vitamin B₁₂ deficiency

Contraindications: Use with rilpivirine

Considerations:

• Has a dual delayed-release formulation for prolonged acid suppression.
• Monitor serum magnesium and vitamin B₁₂ levels with long-term use.
• Review medications for potential interactions.

Question 5

What is the common brand name(s) for:

dicyclomine

(dye-SYE-kloe-meen)

Answer 5

Bentyl

Class: Anticholinergic

Indication: Functional bowel disorders; irritable bowel syndrome-related pain

MOA: Relaxes intestinal smooth muscle by blocking acetylcholine action.

Side effects: xerostomia; dizziness; blurred vision; tachycardia

Contraindications: Intestinal obstruction; obstructive uropathy; glaucoma; myasthenia gravis

Considerations:

• Side effects more pronounced in elderly or preexisting conditions.
• Available in oral and injectable forms.

Question 6

What is the common brand name(s) for:

diphenoxylate; atropine

(dye-fen-OX-i-late; A-troe-peen)

Answer 6

Lomotil

Class: Diphenoxylate – opioid agonist; Atropine – anticholinergic agent

Indication: Acute or chronic diarrhea

MOA: Diphenoxylate binds to μ-opioid receptors, reducing peristalsis; atropine reduces GI secretions.

Side effects: drowsiness; dizziness; dry mouth; constipation

Contraindications: Obstructive jaundice; Clostridioides difficile diarrhea; pediatric patients <6 years

Considerations:

• Generally used for short-term relief of diarrhea.
• Exercise caution in elderly and hepatic impairment.

Question 7

What is the common brand name(s) for:

docusate

(DOK-yoo-sate)

Answer 7

Colace

Class: Surfactant laxative

Indication: Constipation

MOA: Reduces stool surface tension, allowing water and fats to soften stool.

Side effects: mild stomach discomfort; diarrhea; cramping

Contraindications: Known or suspected bowel obstruction or perforation

Considerations:

• Available in capsules, tablets, and liquid.
• Typically administered once or twice daily.
• Should be taken with a full glass of water.

Question 8

What is the common brand name(s) for:

esomeprazole

(es-OM-e-pra-zole)

Answer 8

Nexium

Class: Proton pump inhibitor (PPI)

Indication: GERD; erosive esophagitis; heartburn; H. pylori eradication; NSAID ulcer risk reduction

MOA: Irreversibly binds to and inactivates the proton pump in stomach parietal cells, reducing gastric acid secretion.

Side effects: diarrhea; nausea; headache; B₁₂ deficiency with long-term use

Contraindications: Hypersensitivity to drug or components

Considerations:

• Use caution in elderly and hepatic impairment.
• Typically administered once daily.

Question 9

What is the common brand name(s) for:

famotidine

(fa-MOE-ti-deen)

Answer 9

Pepcid

Class: H₂ (histamine-2) receptor antagonist

Indication: GERD; duodenal and gastric ulcers; stress-related mucosal damage prevention

MOA: Binds to H₂ receptors on gastric parietal cells, inhibiting histamine-mediated acid secretion.

Side effects: headache; dizziness; diarrhea; constipation

Contraindications: Hypersensitivity to drug or components

Considerations:

• Available in oral and intravenous forms.
• Caution in renal impairment; adjustment may be necessary.

Question 10

What is the common brand name(s) for:

granisetron

(gran-EE-se-tron)

Answer 10

Kytril

Class: Selective 5-HT3 Receptor Antagonist

Indication: Antiemetic (chemo and radiation therapy)

MOA: Selective 5-HT3 receptor antagonist, blocks serotonin in chemoreceptor trigger zone.

Side effects: headache; fatigue; constipation; QT prolongation

Contraindications: Hypersensitivity to drug or components

Considerations:

• Used to prevent chemotherapy or radiation-induced nausea.
• Available in oral tablets and intravenous injections.

Question 11

What is the common brand name(s) for:

hyoscyamine

(hye-oh-SYE-a-meen)

Answer 11

Levsin

Class: Anticholinergic (antimuscarinic)

Indication: GI disorders; Parkinsonism

MOA: Competitively binds to muscarinic receptors, suppressing parasympathetic activity.

Side effects: xerostomia; dizziness; blurred vision; tachycardia

Contraindications: Intestinal obstruction; obstructive uropathy; glaucoma; myasthenia gravis

Considerations:

• Available in many formulations.
• Caution in elderly patients due to risk of cognitive impairment.

Question 12

What is the common brand name(s) for:

lactulose

(LAK-tyoo-loes)

Answer 12

Enulose

Non-absorbable synthetic disaccharid

Class: Osmotic laxative

Indication: Chronic constipation; hepatic encephalopathy

MOA: Not absorbed in the GI tract, metabolized by colonic bacteria into acids increasing osmotic pressure.

Side effects: flatulence; bloating; diarrhea; electrolyte imbalances

Contraindications: Patients requiring low-galactose diet

Considerations:

• Sweet taste can be unpalatable.
• Caution in elderly and renal impairment.

Question 13

What is the common brand name(s) for:

lansoprazole

(lan-SOE-pra-zole)

Answer 13

Prevacid

Class: Proton pump inhibitor (PPI)

Indication: GERD; peptic ulcer disease; H. pylori eradication

MOA: Irreversibly binds to and inactivates the proton pump in stomach parietal cells, reducing acid secretion.

Side effects: diarrhea; nausea; headache; skin rash

Contraindications: Use with rilpivirine

Considerations:

• Use caution in elderly and hepatic impairment.
• Typically administered once daily.

Question 14

What is the common brand name(s) for:

linaclotide

(lin-AK-loe-tide)

Answer 14

Linzess

Class: Guanylate cyclase-C (GC-C) agonist

Indication: IBS-C; chronic idiopathic constipation

MOA: Binds to guanylate cyclase-C receptors, increasing intestinal fluid secretion and accelerating transit.

Side effects: diarrhea; abdominal pain; flatulence

Contraindications: Patients <2 years; mechanical GI obstruction

Considerations:

• Typically taken once daily, 30 minutes before first meal.
• Approved for use in adults.

Question 15

What is the common brand name(s) for:

loperamide

(loe-PER-a-mide)

Answer 15

Imodium

Class: Opioid agonists

Indication: Diarrhea

MOA: Binds to Mu-receptors in the intestines, decreasing peristalsis.

Side effects: nausea; headache; drowsiness; torsades de pointes at high dosages

Contraindications: Hypersensitivity to drug or components

Considerations:

• Avoid in pregnancy but acceptable in breastfeeding.
• Avoid in hepatic impairment.

Question 16

What is the common brand name(s) for:

lubiprostone

(loo-bi-PROS-tone)

Answer 16

Amitiza

Class: Osmotic laxative

Indication: Chronic idiopathic constipation; OIC; IBS-C

MOA: Activates type 2 chloride channels, promoting chloride and bicarbonate secretion into the intestinal lumen.

Side effects: nausea; diarrhea; abdominal pain

Contraindications: Mechanical gastrointestinal obstruction

Considerations:

• Set expected onset of action (may take a few days).
• Use caution in elderly patients.

Question 17

What is the common brand name(s) for:

magnesium hydroxide

(mag-NEE-zee-um hye-DROX-ide)

Answer 17

Milk of Magnesia

Class: Antacid and osmotic laxative

Indication: Laxative; antacid

MOA: Neutralizes gastric acid and draws water into the colon by osmosis.

Side effects: diarrhea; abdominal cramps; electrolyte imbalances

Contraindications: Hypersensitivity to drug or components

Considerations:

• Monitor patients, especially with renal impairment.
• Advise patients to stay hydrated.

Question 18

What is the common brand name(s) for:

metoclopramide

(met-oh-KLOE-pra-mide)

Answer 18

Reglan

Class: Dopamine D2 receptor antagonist with additional serotonergic effects

Indication: Nausea and vomiting; gastroparesis; GERD

MOA: Blocks D2 receptors, enhancing GI motility; acts on 5-HT₃ and 5-HT₄ receptors.

Side effects: drowsiness; fatigue; extrapyramidal symptoms; diarrhea

Contraindications: GI obstruction; pheochromocytoma; epilepsy

Considerations:

• Monitor for extrapyramidal symptoms.
• Use caution in pregnancy.

Question 19

What is the common brand name(s) for:

omeprazole

(oh-MEP-ra-zole)

Answer 19

Prilosec

Class: Proton pump inhibitor (PPI)

Indication: Treats GERD; peptic ulcer disease; Zollinger-Ellison syndrome; NSAID-induced ulcers; dyspepsia; Helicobacter pylori

MOA: Irreversibly binds to the H⁺/K⁺-ATPase enzyme in the stomach’s parietal cells, reducing gastric acid production.

Side effects: headache; nausea; diarrhea; abdominal pain; dizziness; increased risk of bone fractures

Contraindications: Hypersensitivity to the drug or its components

Considerations:

• Caution with drugs metabolized by CYP2C19 and CYP3A4.
• Avoid OTC use if experiencing severe symptoms like chest pain or vomiting blood.
• Caution in elderly and those with hepatic impairment.

Question 20

What is the common brand name(s) for:

ondansetron

(on-DAN-se-tron)

Answer 20

Zofran

Class: Selective 5-HT3 Receptor Antagonist

Indication: Used as an antiemetic

MOA: Selective 5-HT3 receptor antagonist that prevents nausea and vomiting by blocking serotonin.

Side effects: headache; fatigue; constipation; QT prolongation; serotonin syndrome

Contraindications: Use with apomorphine

Considerations:

• Consider ECG monitoring with risk factors for arrhythmias.

Question 21

What is the common brand name(s) for:

pantoprazole

(pan-TOE-pra-zole)

Answer 21

Protonix

Class: Proton pump inhibitor (PPI)

Indication: Treats GERD; Zollinger-Ellison syndrome; NSAID-induced ulcers

MOA: Irreversibly binds to the H⁺/K⁺-ATPase enzyme in the stomach’s parietal cells, reducing gastric acid production.

Side effects: headache; nausea; diarrhea; abdominal pain; dizziness; increased risk of bone fractures

Contraindications: Use with rilpivirine

Considerations:

• Caution with drugs metabolized by CYP2C19 and CYP3A4.
• Caution in elderly and those with hepatic impairment.

Question 22

What is the common brand name(s) for:

phenazopyridine

(fen-az-oh-PEER-i-deen)

Answer 22

Pyridium

Class: Urinary tract analgesic

Indication: Used as a urinary analgesic

MOA: Acts locally on the urinary tract.

Side effects: orange or red discoloration of urine; nausea; stomach cramps

Contraindications: Severe renal impairment

Considerations:

• Intended for short-term symptomatic relief.
• Use alongside appropriate treatment for underlying condition.

Question 23

What is the common brand name(s) for:

polyethylene glycol

(pol-ee-ETH-i-leen GLEE-kol)

Answer 23

Miralax

Class: Osmotic laxative

Indication: Treats chronic constipation and used for bowel preparation

MOA: Draws water into the intestinal lumen to increase stool water content.

Side effects: bloating; flatulence; cramping; diarrhea

Contraindications: Bowel obstruction or ileus

Considerations:

• Expected onset of action is within 24–48 hours.
• Caution in pediatric and elderly patients.

Question 24

What is the common brand name(s) for:

prochlorperazine

(proe-KLOR-pair-a-zeen)

Answer 24

Compazine

Class: Antipsychotic, Typical - 1st generation

Indication: Treats migraines; severe nausea/vomiting; schizophrenia

MOA: Dopamine receptor antagonist, especially D2 receptor.

Side effects: cardiac arrhythmia; anticholinergic effects; extrapyramidal symptoms

Contraindications: Children < 2; CNS depression; chronic heavy alcohol use

Considerations:

• ECG monitoring may be required for cardiovascular disease.
• Increased mortality in elderly with dementia-related psychosis.

Question 25

# What is the common brand name(s) for: psyllium | (SIL-ee-um)

Answer 25

Metamucil | Class: Bulk-forming laxative ## Footnote **Indication:** Treats constipation and used as a dietary fiber supplement **MOA:** Absorbs water to form a gel that stimulates peristalsis. **Side effects:** bloating; flatulence; abdominal cramping **Contraindications:** Gastrointestinal obstruction **Considerations:** * Take with a full glass of water. * Take other drugs at least 1–2 hours before or after psyllium.

Question 26

# What is the common brand name(s) for: rifaximin | (ri-FAKS-i-min)

Answer 26

Xifaxan | Class: Rifamycin antibiotic ## Footnote **Indication:** Treats traveler's diarrhea; hepatic encephalopathy; IBS; off-label for Clostridium difficile colitis **MOA:** Inhibits DNA-dependent RNA polymerase. **Side effects:** nausea; vomiting; abdominal pain; headache **Contraindications:** Hypersensitivity to the drug or its components **Considerations:** * Not effective in patients with fever or blood in the stool.

Question 27

# What is the common brand name(s) for: scopolamine | (skoe-POL-a-meen)

Answer 27

Transderm Scop | Class: Anticholinergic ## Footnote **Indication:** Treats motion sickness and used as a preoperative antiemetic **MOA:** Blocks acetylcholine transmission to the vomiting center. **Side effects:** anticholinergic effects like xerostomia; dizziness **Contraindications:** Narrow-angle glaucoma **Considerations:** * Available in transdermal patch, oral, and injectable forms. * Caution with CNS depressants or anticholinergic medications.

Question 28

# What is the common brand name(s) for: senna | (SEN-a)

Answer 28

Senokot | Class: Stimulant laxative ## Footnote **Indication:** Treats constipation and used for bowel prep **MOA:** Irritates intestinal mucosa to stimulate peristalsis. **Side effects:** intestinal contractions; diarrhea; electrolyte imbalances **Contraindications:** Use for >7 days; with mineral oil; or with abdominal pain **Considerations:** * Recommended for short-term relief. * Caution in elderly and pediatric patients.

Question 29

# What is the common brand name(s) for: sucralfate | (SOO-kral-fate)

Answer 29

Carafate | Class: Gastrointestinal mucosal protectant ## Footnote **Indication:** Treatment of active duodenal ulcers **MOA:** Forms a viscous, sticky substance in the stomach that binds to ulcer sites. **Side effects:** constipation; nausea; risk of aluminum accumulation **Contraindications:** Hypersensitivity to the drug or its components **Considerations:** * Administer on an empty stomach, typically 1 hour before meals. * May interfere with the absorption of other drugs.