Pharm Drugs Part 1

Answer: E
(Katzung, pp 1041, Brunton, pp 979)
A variety of regimens have been used to eradicate Helicobacter pylori, each with different dosing
schedules, adverse effects and cost. Combination therapy with 2 or 3 antibiotics plus a H2-
antagonist or a proton pump inhibitor, is associated with the highest rate of eradication.
Antibiotics effective against H. pylori include amoxicillin, clarithromycin, metronidazole and
tetracycline. Bismuth salt are included in some regimens but they are less effective and more costly
than regimens with 2 antibiotics.
A, B, C, D) All these regimens do not include 2 antibiotics and a H2-antagonist or a proton pump
inhibitor. Moreover antacids and sucralfate are not effective to eradicate H. pylori.

Omeprazole is a proton pump inhibitor (PPI) that is used as an antiulcer agent. It works by inhibiting the enzyme responsible for the final step in gastric acid secretion, leading to a decrease in the production of stomach acid. Studies have shown that omeprazole can inhibit gastric acid secretion by about 80-95% over a 24-hour period, making it an effective choice for reducing acid production in the stomach.

Answer: E
(Katzung, pp 1041, Brunton, pp 980)
The patient is most likely suffering from Zollinger-Ellison syndrome, a rare condition characterized
by a triad of clinical findings, which include severe recurrent peptic ulcer disease, significant
hypersecretion of gastric acid and a tumor of the pancreas (gastrinoma) which functions as an
ectopic source of gastrin. This tumor is located primarily in the pancreas but can be found in other
regions, particularly duodenum. Today most patients with gastrinoma can be effectively treated with
high dose of a drug (like omeprazole) able to Inhibit H+/K+ ATPase of gastric parietal cells.
A) H2-receptors antagonists are less effective than proton pump inhibitors in reducing gastric acid
secretion and therefore are not the drugs of choice in Zollinger-Ellison syndrome.
B) This would be the mechanism of action of misoprostol.
C) This would be the mechanism of action of sucralfate.
D) This would be the mechanism of action of antacids.

Mesalamine is a salicylate derivative commonly used in the treatment of inflammatory bowel diseases such as ulcerative colitis and Crohn's disease. It works by reducing inflammation in the colon and rectum, helping to relieve symptoms such as diarrhea, abdominal pain, and rectal bleeding. Mesalamine is available in various forms, including oral tablets, capsules, and rectal suppositories or enemas. It is considered a first-line treatment for mild to moderate inflammatory bowel diseases and can also be used for maintenance therapy to prevent flare-ups.

Sucralfate is an antiulcer agent that works by binding to the necrotic tissue of a peptic ulcer. This binding forms a protective barrier over the ulcer, preventing further damage from gastric juice.

Loperamide is an opioid drug that is commonly used to treat diarrhea. It works by slowing down the movement of the intestines, which helps to reduce the frequency and urgency of bowel movements. Loperamide is available over-the-counter and is often used to manage acute diarrhea or chronic diarrhea associated with conditions such as irritable bowel syndrome. It is not recommended for use in cases of diarrhea caused by infection or inflammatory bowel disease.

Magnesium hydroxide is an antacid that also has laxative properties. It works by neutralizing excess stomach acid to relieve heartburn, indigestion, and upset stomach. Additionally, magnesium hydroxide can help to relieve constipation by drawing water into the intestines, softening the stool, and promoting bowel movements.

Misoprostol is a prostaglandin E1 analogue that is known to have a cytoprotective effect on the gastric mucosa. It helps to prevent gastric ulcers by increasing the production of mucus and bicarbonate in the stomach, and by reducing the secretion of gastric acid. This cytoprotective effect makes Misoprostol an effective medication for preventing gastric ulcers caused by nonsteroidal anti-inflammatory drugs (NSAIDs) or for treating ulcers caused by Helicobacter pylori infection.

Methylcellulose is a drug that is commonly used as a bulk-forming laxative. It works by absorbing water in the intestine, which then increases the size and moisture content of the stool. This helps to stimulate peristaltic activity, or the movement of the intestines, leading to increased bowel movements and relief from constipation.

Answer: D
(Katzung, pp 1040, Koda-Kimble , pp 27-20)
The substernal pain and reflux of gastric content into the esophagus are classic symptoms of
gastroesophageal reflux disease (GERD) a disorder that affects 7% of the population in USA.
Proton pump inhibitor like omeprazole are highly effective in the treatment of GERD and once daily
dose for 4 weeks will heel 60-80% of patient with severe esophagitis.
A) Atropine is actually contraindicated since it may favor reflux by relaxing the lower esophageal
sphincter
B, C) These drugs are not effective in GERD.
E) Metoclopramide is used in the treatment of GERD because it promotes gastric peristalsis and
also increases the lower esophageal sphincter resting tone. However it is contraindicated in patients
with Parkinson disease, since it is a D2 antagonist.
F) H2-antagonists are less effective that proton pump inhibitors in GERD. Moreover cimetidine is
not appropriate in a patient taking other drugs since it inhibits the metabolism of most drugs,
including selegiline.

Answer: A
(Katzung, pp 1046, Brunton, pp 993)
Lactulose is a non-absorbable sugar which is hydrolyzed in the colon to organic acids. These acids
draw water into the lumen by osmotic forces, so stimulating colonic propulsive motility by stretching
the colonic wall. The laxative effect is mild.
B) Castor oil is a too strong cathartic to be used regularly.
C, D) Magnesium and phosphate preparation are contraindicated in renal insufficiency since the
small amount of absorbed salt cannot be readily excreted so causing systemic toxicity
(hypermagnesemia or hyperphosphatemia.)
E) Mineral oil has several adverse effects (interference with absorption of fat soluble substances,
elicitation of foreign-body reaction) which preclude its regular use.

Answer: C
(Katzung, pp 1045, Brunton, pp 985)
Prokinetic drugs like metoclopramide have been widely used for treatment of patients with delayed
gastric emptying due to surgery or diabetic gastroparesis. The improvement of gastric emptying is
mild to modest in most cases.
A, B, D, E, F) These drugs are devoid of prokinetic properties.

Pharmacokinetics
o Oral (aprepitant) and parenteral (fosaprepitant) administration
o Fosaprepitant undergoes metabolic conversion to aprepitant within 30 min of administration
o Oral bioavailability ~65%
o Readily crosses the blood-brain barrier
o Undergoes hepatic metabolism, primarily by CYP3A4
 Pharmacodynamics
o Mechanism of Action
 Antagonism of brain NK1-receptors
Pharmacological Actions/Effects
 Antiemetic properties
 Due to central blockade in the area postrema
 Clinical Pharmacology

*********** Clinical Uses*********
Used in combination with glucocorticoids and 5-HT3-receptor antagonists for the preventation of acute and delayed nausea and vomiting from highly emetogenic chemotherapeutic regimens

****************
 80-90% success in cases of acute emesis
 >70% success in cases of delayed emesis
o Adverse Effects/Toxicity
 Aprepitant
 Serious reactions
o Neutropenia, bradycardia, dehydration, angioedema, Stevens-Johnson syndrome
 Common reactions
o Fatigue, nausea/vomiting, hiccups, constipation, diarrhea, anorexia, headache, dizziness, pruritus, hypotension, bradycardia, dehydration, heartburn, abdominal pain, gastritis, tinnitus, neutropenia, fever, insomnia, mucositis, flatulence, anemia

Erythromycin is a macrolide antibiotic that can also act as a motilin receptor agonist. Motilin receptors are found in the upper gastrointestinal tract and their activation increases gastrointestinal motility. Therefore, erythromycin can increase upper gastrointestinal motility by directly stimulating these receptors.

omeprazole decreases from 90 to 98%