Pharmacology Exam 5 Review
Pharmacology Exam 5 Review:
Chapter 50 PHARM
Hydrochloric Acid
• Secreted by parietal cells when stimulated by food, caffeine, chocolate, and alcohol
• Maintains stomach at pH of 1 to 4
• Acidity aids in the proper digestion of food and defenses against microbial
infection via the gastrointestinal (GI) tract.
• Secretion also stimulated by:
• Large fatty meals
• Emotional stress
• Caffeine, alcohol
Parietal cell wall contains 3 receptors acetylcholine, histamine,
and Acid-Related Diseases
• Peptic ulcer disease (PUD)
• Gastric or duodenal ulcers that involve digestion of the GI mucosa by the
enzyme pepsin
• Helicobacter pylori (H. pylori) If elder patient has it then they most likely have ulcers
• Bacterium found in GI tract of 90% of patients with duodenal ulcers and 70%
of those with gastric ulcers
• First-line therapy includes a 10- to 14-day course of a proton pump inhibitor
(PPI) and the antibiotics clarithromycin and either amoxicillin or metronidazole
or a combination of a PPI, bismuth subsalicylate, and the antibiotics tetracycline
and metronidazole.
• Stress-related mucosal damage
• GI lesions are a common finding in intensive care unit (ICU) patients,
especially within the first 24 hours after admission.
• Factors include decreased blood flow, mucosal ischemia, hypoperfusion,
and reperfusion injury.
• Nasogastric (NG) tubes and ventilators predispose patients to GI bleeding.
• A histamine receptor–blocking drug or a PPI are given for prevention.
• Data do not support the continued use of stress ulcer prophylaxis after
the patient is no longer in the ICU.
• Needs to be on continuous suction (intermittent) when nasogastric tube is in place
Types of Acid-Controlling Drugs
• Antacids (most used medication to control acid of the stomach) Primary function is
to neutralize the acid secretions.
• H2 antagonists
• PPIs
• Antacids: Acute relief of symptoms associated with peptic ulcer, gastritis,
gastric hyperacidity, and heartburn
• Basic compounds used to neutralize stomach acid
• Salts of aluminum, magnesium, calcium, and/or sodium
• Many antacid preparations also contain the antiflatulent (antigas) drug simethicone.
• Many aluminum- and calcium-based formulations also include magnesium, which not only
contributes to the acid-neutralizing capacity but also counteracts the constipating effects
of aluminum and calcium.
• Calcium antacids may lead to the development of kidney stones and increased gastric
acid secretion.
,Pharmacology Exam 5 Review
• Antacids containing magnesium must be avoided in patients with renal failure.
• Sodium bicarbonate is a highly soluble antacid form with a quick onset but short duration
of action.
Mechanism of action:
• Do not prevent the overproduction of acid but instead help to neutralize acid secretions
• Promote gastric mucosal defense mechanisms
• Stimulate secretion of:
• Mucus: protective barrier against HCl
• Bicarbonate: helps buffer acidic properties of HCl
• Prostaglandins: prevent activation of proton pump
Effects:
• Reduction of pain associated with acid-related disorders
• Raising the gastric pH 1 point (1.3 to 2.3) neutralizes 90% of the gastric acid.
• Reducing acidity reduces pain as a result of:
• Base-mediated inhibition of the protein-digesting ability of pepsin
• Increase in the resistance of the stomach lining to irritation
• Increase in the tone of the cardiac sphincter
Counter indications:
• Known allergy to a specific drug product
• Severe renal failure or electrolyte disturbances: potential toxic accumulation of
electrolytes in the antacids themselves
• GI obstruction: antacids may stimulate GI motility when they are undesirable because of
the presence of an obstructive process requiring surgical intervention
Antacids: Aluminum Salts (be careful for patients with renal failure)
• Have constipating effects
• Often used with magnesium to counteract constipation
• Often recommended for patients with renal disease (more easily excreted)
• Examples
• Aluminum carbonate: Basaljel
• Hydroxide salt: AlternaGEL
• Combination products (aluminum and magnesium): Gaviscon, Maalox, Mylanta,
Di- Gel
Antacids: Magnesium Salts
• Commonly cause diarrhea; usually used with other drugs to counteract this effect
• Dangerous when used with renal failure; the failing kidney cannot excrete extra
magnesium, resulting in accumulation.
• Hydroxide salt: magnesium hydroxide (Milk of Magnesia)
• Carbonate salt: Gaviscon (also a combination product)
• Combination products such as Maalox, Mylanta (aluminum and magnesium)
Antacids: Calcium Salts
• Many forms but carbonate is most common
• May cause constipation, kidney stones
• Also not recommended for patients with renal disease—may accumulate to toxic levels
• Long duration of acid action—may cause increased gastric acid secretion
(hyperacidity rebound)
• Often advertised as an extra source of dietary calcium
• Example: Tums (calcium carbonate)
Sodium bicarbonate (May cause metabolic
alkalosis) Antacids Adverse effects:
, Pharmacology Exam 5 Review
• Minimal and depend on the compound used
• Overuse: metabolic alkalosis
• Aluminum and calcium: constipation
• Magnesium: diarrhea
• Calcium: kidney stones, rebound hyperacidity
• Calcium carbonate: produces gas and belching; often combined with simethicone
Histamine 2 (H2) Receptor Antagonists
• Reduce acid secretion (Most popular treatment for any gastric related
illnesses) completely block H2 parietal cells.
• All available OTC in lower dosage forms
• Most popular drugs for treatment of acid-related disorders
• cimetidine (Tagamet)
• nizatidine (Axid)
• famotidine (Pepcid)
• ranitidine (Zantac)
Mechanism of action:
• Competitively block the H2 receptor of acid-producing parietal cells
• Reduced hydrogen ion secretion from the parietal cells
• Increase in the pH of the stomach
• Relief of many of the symptoms associated with hyperacidity-related conditions
Drug effect
• Suppressed acid secretion in the stomach
Indications
• Gastroesophageal reflux disease (GERD)
• PUD
• Erosive esophagitis
• Adjunct therapy to control upper GI bleeding
• Zollinger-Ellison syndrome
Adverse effects:
• Overall, very few adverse effects
• Central nervous system adverse effects in elderly patients include confusion
and disorientation.
• Cimetidine may induce impotence and gynecomastia.
• Thrombocytopenia has been reported with ranitidine and famotidine.
Cimetidine (Tagamet)
• Binds with P-450 microsomal oxidase system in the liver, resulting in
inhibited oxidation of many drugs and increased drug levels
• All H2 antagonists may inhibit the absorption of drugs that require an acidic
GI environment for absorption.
• Because of its potential to cause drug interactions, cimetidine has been
largely replaced by ranitidine and famotidine.
• Cimetidine is still used to treat certain allergic reactions.
• For optimal results, H2 receptor antagonists are taken 1 to 2 hours
before antacids.
PPI’s gave as first line of medication
• The parietal cells release positive hydrogen ions (protons) during HCl production.
• This process is called the proton pump.
• H2 blockers and antihistamines do not stop the action of this pump
• Blocks over 90% of acid secretion in 24 hour
period Mechanism of action
Pharmacology Exam 5 Review:
Chapter 50 PHARM
Hydrochloric Acid
• Secreted by parietal cells when stimulated by food, caffeine, chocolate, and alcohol
• Maintains stomach at pH of 1 to 4
• Acidity aids in the proper digestion of food and defenses against microbial
infection via the gastrointestinal (GI) tract.
• Secretion also stimulated by:
• Large fatty meals
• Emotional stress
• Caffeine, alcohol
Parietal cell wall contains 3 receptors acetylcholine, histamine,
and Acid-Related Diseases
• Peptic ulcer disease (PUD)
• Gastric or duodenal ulcers that involve digestion of the GI mucosa by the
enzyme pepsin
• Helicobacter pylori (H. pylori) If elder patient has it then they most likely have ulcers
• Bacterium found in GI tract of 90% of patients with duodenal ulcers and 70%
of those with gastric ulcers
• First-line therapy includes a 10- to 14-day course of a proton pump inhibitor
(PPI) and the antibiotics clarithromycin and either amoxicillin or metronidazole
or a combination of a PPI, bismuth subsalicylate, and the antibiotics tetracycline
and metronidazole.
• Stress-related mucosal damage
• GI lesions are a common finding in intensive care unit (ICU) patients,
especially within the first 24 hours after admission.
• Factors include decreased blood flow, mucosal ischemia, hypoperfusion,
and reperfusion injury.
• Nasogastric (NG) tubes and ventilators predispose patients to GI bleeding.
• A histamine receptor–blocking drug or a PPI are given for prevention.
• Data do not support the continued use of stress ulcer prophylaxis after
the patient is no longer in the ICU.
• Needs to be on continuous suction (intermittent) when nasogastric tube is in place
Types of Acid-Controlling Drugs
• Antacids (most used medication to control acid of the stomach) Primary function is
to neutralize the acid secretions.
• H2 antagonists
• PPIs
• Antacids: Acute relief of symptoms associated with peptic ulcer, gastritis,
gastric hyperacidity, and heartburn
• Basic compounds used to neutralize stomach acid
• Salts of aluminum, magnesium, calcium, and/or sodium
• Many antacid preparations also contain the antiflatulent (antigas) drug simethicone.
• Many aluminum- and calcium-based formulations also include magnesium, which not only
contributes to the acid-neutralizing capacity but also counteracts the constipating effects
of aluminum and calcium.
• Calcium antacids may lead to the development of kidney stones and increased gastric
acid secretion.
,Pharmacology Exam 5 Review
• Antacids containing magnesium must be avoided in patients with renal failure.
• Sodium bicarbonate is a highly soluble antacid form with a quick onset but short duration
of action.
Mechanism of action:
• Do not prevent the overproduction of acid but instead help to neutralize acid secretions
• Promote gastric mucosal defense mechanisms
• Stimulate secretion of:
• Mucus: protective barrier against HCl
• Bicarbonate: helps buffer acidic properties of HCl
• Prostaglandins: prevent activation of proton pump
Effects:
• Reduction of pain associated with acid-related disorders
• Raising the gastric pH 1 point (1.3 to 2.3) neutralizes 90% of the gastric acid.
• Reducing acidity reduces pain as a result of:
• Base-mediated inhibition of the protein-digesting ability of pepsin
• Increase in the resistance of the stomach lining to irritation
• Increase in the tone of the cardiac sphincter
Counter indications:
• Known allergy to a specific drug product
• Severe renal failure or electrolyte disturbances: potential toxic accumulation of
electrolytes in the antacids themselves
• GI obstruction: antacids may stimulate GI motility when they are undesirable because of
the presence of an obstructive process requiring surgical intervention
Antacids: Aluminum Salts (be careful for patients with renal failure)
• Have constipating effects
• Often used with magnesium to counteract constipation
• Often recommended for patients with renal disease (more easily excreted)
• Examples
• Aluminum carbonate: Basaljel
• Hydroxide salt: AlternaGEL
• Combination products (aluminum and magnesium): Gaviscon, Maalox, Mylanta,
Di- Gel
Antacids: Magnesium Salts
• Commonly cause diarrhea; usually used with other drugs to counteract this effect
• Dangerous when used with renal failure; the failing kidney cannot excrete extra
magnesium, resulting in accumulation.
• Hydroxide salt: magnesium hydroxide (Milk of Magnesia)
• Carbonate salt: Gaviscon (also a combination product)
• Combination products such as Maalox, Mylanta (aluminum and magnesium)
Antacids: Calcium Salts
• Many forms but carbonate is most common
• May cause constipation, kidney stones
• Also not recommended for patients with renal disease—may accumulate to toxic levels
• Long duration of acid action—may cause increased gastric acid secretion
(hyperacidity rebound)
• Often advertised as an extra source of dietary calcium
• Example: Tums (calcium carbonate)
Sodium bicarbonate (May cause metabolic
alkalosis) Antacids Adverse effects:
, Pharmacology Exam 5 Review
• Minimal and depend on the compound used
• Overuse: metabolic alkalosis
• Aluminum and calcium: constipation
• Magnesium: diarrhea
• Calcium: kidney stones, rebound hyperacidity
• Calcium carbonate: produces gas and belching; often combined with simethicone
Histamine 2 (H2) Receptor Antagonists
• Reduce acid secretion (Most popular treatment for any gastric related
illnesses) completely block H2 parietal cells.
• All available OTC in lower dosage forms
• Most popular drugs for treatment of acid-related disorders
• cimetidine (Tagamet)
• nizatidine (Axid)
• famotidine (Pepcid)
• ranitidine (Zantac)
Mechanism of action:
• Competitively block the H2 receptor of acid-producing parietal cells
• Reduced hydrogen ion secretion from the parietal cells
• Increase in the pH of the stomach
• Relief of many of the symptoms associated with hyperacidity-related conditions
Drug effect
• Suppressed acid secretion in the stomach
Indications
• Gastroesophageal reflux disease (GERD)
• PUD
• Erosive esophagitis
• Adjunct therapy to control upper GI bleeding
• Zollinger-Ellison syndrome
Adverse effects:
• Overall, very few adverse effects
• Central nervous system adverse effects in elderly patients include confusion
and disorientation.
• Cimetidine may induce impotence and gynecomastia.
• Thrombocytopenia has been reported with ranitidine and famotidine.
Cimetidine (Tagamet)
• Binds with P-450 microsomal oxidase system in the liver, resulting in
inhibited oxidation of many drugs and increased drug levels
• All H2 antagonists may inhibit the absorption of drugs that require an acidic
GI environment for absorption.
• Because of its potential to cause drug interactions, cimetidine has been
largely replaced by ranitidine and famotidine.
• Cimetidine is still used to treat certain allergic reactions.
• For optimal results, H2 receptor antagonists are taken 1 to 2 hours
before antacids.
PPI’s gave as first line of medication
• The parietal cells release positive hydrogen ions (protons) during HCl production.
• This process is called the proton pump.
• H2 blockers and antihistamines do not stop the action of this pump
• Blocks over 90% of acid secretion in 24 hour
period Mechanism of action
