Module 6 - GI Disorders Flashcards
What type of drug is Cimetidine (Tagamet) and what is its MOA?
- Type: Histamine 2 Receptor Antagonist
- MOA: histamine-2 blockers are reversible competitive blockers of histamine at the H2 receptors, particularly those in the gastric parietal cells, causing a dose-dependent inhibition of gastric acid secretion. They are highly selective, do not affect the H1 receptors, and are not anticholinergic agents. They are effective in alleviating symptoms and in preventing complications of peptic ulcer disease
THIS IS THE PROTOTYPE DRUG
What are the indications for using Cimetidine [Tagamet]?
Cimetidine is indicated in the treatment of active duodenal and benign gastric ulcers, prophylaxis of duodenal ulcers, treatment of acid hypersecretory conditions (e.g., Z-E syndrome), erosive esophagitis, upper GI bleeding, and management of gastroesophageal reflux disease (GERD).
What are the s/x associated with Cimetidine [Tagamet]?
- large doses of cimetidine given to patients unable to eliminate the drug may develop central effects such as severe agitation, slurred speech, confusion, & delirium.
- This is especially applicable to the elderly or subjects with renal impairment.
- Prolonged effect of cimetidine may produce an antiandrogenic effect (gynecomastia; reduced sperm count in men; galactorrhea in women), but this is rare.
- Decrease in gastric acid (i.e., increase in pH above 5) increases growth of bacteria in the stomach and increases the risk of pneumonia.
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What type of drug is Omeprazole and what is its MOA?
- Type: Proton Pump Inhibitor
- MOA: MOA: PPIs suppress gastric acid secretion (both fasting and meal–stimulated) by specific irreversible inhibition of the H+/K+ ATPase enzyme system (termed proton pump inhibitors) at the secretory surface of the gastric parietal cell. This is the final phase in acid secretion. The PPIs are the most effective drugs we have for suppressing gastric acid secretion.
What are the indications for using Omeprazole?
The proton pump inhibitors are indicated in gastroesophageal reflux disease (GERD) (1st line therapy) and pathological hypersecretory conditions (e.g., Z-E syndrome) as well as in the treatment of duodenal ulcers, and, with clarithromycin, in eradication of H. pylori
What are some drug interactions associated with omeprazole?
- Omeprazole inhibits hepatic enzymes and has increased drug blood levels in patients taking diazepam, flurazepam, triazolam, phenytoin, and warfarin.
- Omeprazole is metabolized by CYP2C19
- It also decreased tacrolimus serum concentrations about 15%
What are the s/x associated with omeprazole?
- The PPIs are well tolerated and cause few side effects (nausea, headache, and abdominal pain).
- Long-term suppression of acid may allow bacteria overgrowth in the gut including Clostridium difficile.
- Discontinuation of PPIs may result in acid rebound.
- Studies suggest PPIs increase the risk of osteoporosis.
What type of drug is Metoclopramide (Reglan) and what is its MOA?
- Type: Promotility agent
- MOA: The mode of action is unclear but it appears to block dopamine (D2) receptors in the GI tract and sensitize tissues to the action of acetylcholine. It increases the tone and amplitude of gastric contractions, relaxes the pyloric sphincter and duodenal bulb, and increases peristalsis
What is the indications for using Metoclopramide (Reglan)?
Metoclopramide is indicated for the treatment of diabetic gastroparesis, symptomatic gastroesophageal reflux, and nausea & vomiting associated with emetogenic cancer chemotherapy.
What are the s/x associated with Metoclopramide (Reglan)?
Because of this drug blocks dopamine receptors in the CNS it:
- May produce depression & extrapyramidal symptoms.
- Metoclopramide has been reported to cause tardive dyskinesia. Warning against using with MAO inhibitors
What type of drug is Polyethylene Glycol electrolyte solution (PEG) and what is its MOA?
- Type: Hyperosmotic laxatives
- MOA: It is an isosmotic, non-absorbable liquid that should pass through the bowel without net absorption; they induce diarrhea within 30-60 min after initiation of therapy.
What are the indications for using Polyethylene Glycol electrolyte solution (PEG) and what are the s/x associated with it?
- PEG solutions used prior to GI exams (e.g., colonoscopy).
- The large volume of fluid and salty taste can cause nausea and sometimes vomiting. About 10% of patients are not able to finish drinking the required amount.
What type of drug is Loperamide (Imodium) and what is its MOA?
- Type: Antidiarrheal
- MOA: It is a narcotic derivative that is relatively free of analgesic, euphoric or abuse-promoting effects but has a predominant effect on the gut. It decreases propulsive movements, allowing more time for water to be absorbed from fecal contents
What are the indications for using Loperamide (Imodium)?
- These agents are used generally for management of acute diarrhea of nonspecific origin, or chronic diarrhea caused by inflammatory bowel disease, or traveler’s diarrhea.
- It is the 1st line therapy for IBS because it causes the least CNS activity
What are the s/x of taking diphenoxylate (Lomotil)?
- Lomotil contains a subtherapeutic dose of atropine to produce unpleasant effects if taken in overdose, thus discourages abuse.
- Side effects of Lomotil include drowsiness, dry mouth, abdominal cramps & dizziness. Euphoria has been reported.
