Acid controlling drugs Flashcards
The stomach secretes
Hydrochloric acid (HCl)
Bicarbonate
Pepsinogen
Intrinsic factor
Mucus
Prostaglandins
- Glands of the Stomach
- Which gland are the largest in number and of primary importance when discussing acid control?
Cardiac
Pyloric
Gastric
-The cells of the gastric gland are the largest in number and of primary importance when discussing acid control.
Cells of the Gastric Gland
Parietal
Chief
Mucous
Endocrine
Enterochromaffin
Parietal cells
Produce and secrete hydrochloric acid
Primary site of action for many of the drugs used to treat acid-related disorders
Chief cells
Secrete pepsinogen, a proenzyme
Pepsinogen becomes pepsin when activated by exposure to acid.
Pepsin breaks down proteins (proteolytic).
Mucous cells
Mucus-secreting cells (surface epithelial cells)
Provide a protective mucus coat
Protect against self-digestion by hydrochloric acid and digestive enzymes
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 tract.
HCL Secretion also stimulated by:
Large fatty meals
Emotional stress
Peptic ulcer disease
Gastric or duodenal ulcers that involve digestion of the gastrointestinal mucosa by the enzyme pepsin
Helicobacter pylori (H. pylori)
- About
- Therapy
Bacterium found in gastrointestinal tract of 90% of patients with duodenal ulcers and 70% of those with gastric ulcers
Triple therapy includes a 7- to 14-day course of a proton pump inhibitor (PPI) and the antibiotics clarithromycin and either amoxicillin or metronidazole or quadruple therapy of a PPI, bismuth subsalicylate, and the antibiotics tetracycline and metronidazole.
Stress-related mucosal damage
Gastrointestinal lesions are a common finding in Critical Care Unit patients, especially within the first 24 hours after admission.
Factors include decreased blood flow, mucosal ischemia, hypoperfusion, and reperfusion injury.
Nasogastric tubes and ventilators predispose patients to gastrointestinal bleeding.
A histamine receptor–blocking drug or a PPI are given for prevention.
3 Types of Acid-Controlling Drugs
Antacids
-Calcium antacids
-Antacids with Mg
-Sodium bicarbonate
H2 antagonists
-ranitidine hydrochloride (Zantac®)
-famotidine (Pepcid®)
PPIs
-lansoprazole (Prevacid®)
-omeprazole (Losec®)
-pantoprazole sodium (Pantoloc®)
Antacids
Basic compounds used to neutralize stomach acid
Salts of aluminum, magnesium, calcium, or sodium bicarbonate, or all of these
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.
Antacids containing magnesium
must be avoided in patients with renal failure.
Sodium bicarbonate
is a highly soluble antacid form with a quick onset but a short duration of action.
Antacids: Mechanism of Action
Do not prevent the overproduction of acid but instead help to neutralize acid secretions
Promote gastric mucosal defensive mechanisms
Stimulate secretion of:
Mucus, Bicarbonate, Prostaglandins
Mucus
protective barrier against hydrochloric acid
Bicarbonate
helps buffer acidic properties of hydrochloric acid
Prostaglandins
prevent activation of proton pump
Antacids: Drug Effects
Reduction of pain and reflux 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
Antacids: Indications
Acute relief of symptoms associated with peptic ulcer, gastritis, gastric hyperacidity, and heartburn
Antacids: Contraindications
Known allergy to a specific drug product
Severe renal failure or electrolyte disturbances: potential toxic accumulation of electrolytes in the antacids themselves
Gastrointestinal obstruction: Antacids may stimulate gastrointestinal motility when they are undesirable because of the presence of an obstructive process requiring surgical intervention.
Antacids Over-the-counter (OTC) formulations available as:
Capsules and tablets
Powders
Chewable tablets
Suspensions
Effervescent granules and tablets
Antacids: 4 Types
Used alone or in combination
Aluminum hydroxide
Magnesium hydroxide
simethicone
Combination aluminum hydroxide and magnesium hydroxide contain a local anaesthetic (Mucaine®).
Antacids: Aluminum Salts
Have constipating effects
Often used with magnesium to counteract constipation
Often recommended for patients with renal disease (more easily excreted)
Examples
Combination products (aluminum and magnesium): Antacid Plus®, Diovol®, Gelusil®, Maalox®, Multiaction®
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
Magnesium hydroxide and mineral oil (Magnolox®)
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: calcium carbonate and simethicone (Maalox, Rolaids®)
Antacids: Sodium Bicarbonate
Highly soluble
Buffers the acidic properties of hydrochloric acid
Quick onset but short duration
May cause metabolic alkalosis
Sodium content may cause problems in patients with heart failure, hypertension, or renal insufficiency.
Antiflatulents
used to relieve the painful symptoms associated with gas
simethicone
antacid and antiflatulents
used to bind or alter intestinal gas and are often added to antacid combination products.
Antacids: Adverse Effects
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
Antacids: Drug Interactions
Adsorption of other drugs to antacids
-Reduces the ability of the other drug to be absorbed into the body
Chelation
-Chemical binding, or inactivation, of another drug
-Produces insoluble complexes
-Result: reduced drug absorption
Increased stomach pH
-Increased absorption of basic drugs
-Decreased absorption of acidic drugs
Increased urinary pH
-Increased excretion of acidic drugs
-Decreased excretion of basic drugs
Increased stomach pH
-Increased absorption of basic drugs
-Decreased absorption of acidic drug
Increased urinary pH
-Increased excretion of acidic drugs
-Decreased excretion of basic drugs
H2 Receptor Antagonists
2 drugs
ranitidine hydrochloride (Zantac®)
famotidine (Pepcid®)
H2 Receptor Antagonists facts
Reduce acid secretion
All available OTC in lower-dosage forms
Most popular drugs for treatment of acid-related disorders
H2 Antagonists: Mechanism of Action
Competitively block the H2 receptor of acid-producing parietal cells
Reduce hydrogen ion secretion from the parietal cells
Increase in the pH of the stomach
Relieve of many of the symptoms associated with hyperacidity-related conditions
H2 Antagonists: Drug Effect: Indications
Gastroesophageal reflux disease (GERD)
Peptic ulcer disease
Erosive esophagitis
Adjunct therapy to control upper gastrointestinal bleeding
Zollinger-Ellison syndrome
H2 Antagonists
Drug effect:
Suppressed acid secretion in the stomach
H2 Antagonists: Adverse Effects
Overall, very few adverse effects
Central nervous system adverse effects in elderly patients include confusion and disorientation.
Cimetidine may causes erectile dysfunction and gynecomastia.
Thrombocytopenia has been reported with ranitidine hydrochloride and famotidine.
H2 Antagonists: Drug Interactions
cimetidine:
cimetidine:
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 gastrointestinal 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.
All H2 antagonists may inhibit the absorption of drugs that require an?
acidic gastrointestinal environment for absorption.
H2 Antagonists: Drug Interactions
Smoking has been shown to decrease the effectiveness of H2 blockers.
For optimal results, H2 receptor antagonists are taken 1 hour before antacids.
Proton Pump Inhibitors
The parietal cells release positive hydrogen ions (protons) during hydrochloric acid production.
This process is called the proton pump.
H2 blockers and antihistamines do not stop the action of this pump.
Proton Pump Inhibitors medications
lansoprazole (Prevacid®)
omeprazole (Losec®)
pantoprazole sodium (Pantoloc®)
Proton Pump Inhibitors: Mechanism of Action
Irreversibly bind to H+/K+ adenosine triphosphatase (ATPase) enzyme
This bond prevents the movement of hydrogen ions from the parietal cell into the stomach.
Results in achlorhydria—all gastric acid secretion is temporarily blocked.
-To return to normal acid secretion, the parietal cell must synthesize new H+/K+ ATPase.
Proton Pump Inhibitors: Indications
Gastroesophageal reflux disease
Erosive esophagitis
Short-term treatment of active duodenal and benign gastric ulcers
Zollinger-Ellison syndrome
Nonsteroidal anti-inflammatory drug (NSAID)–induced ulcers
Stress ulcer prophylaxis
Treatment of H. pylori–induced infections
Given with an antibiotic
Proton Pump Inhibitors: Adverse Effects
Protein pump inhibitors (PPIs) are generally well tolerated.
Possible predisposition to gastrointestinal tract infections: Clostridium difficile
Osteoporosis and risk of wrist, hip, and spine fractures in long-term users
Pneumonia
Depletion of magnesium
Proton Pump Inhibitors: Drug Interactions
Increase serum levels of diazepam and phenytoin
warfarin: increased chance of bleeding
Absorption of ketoconazole, ampicillin, iron salts, and digoxin
clopidogrel
sucralfate: may delay the absorption of PPIs
Food may decrease absorption of the PPIs.
Miscellaneous Acid-Controlling Drugs
sucralfate
misoprostol
simethicone (Ovol®)
Sucralfate
Miscellaneous Acid-Controlling Drugs
Cytoprotective drug
Used for stress ulcers, peptic ulcer disease
Attracted to and binds to the base of ulcers and erosions, forming a protective barrier over these areas
Protects these areas from pepsin, which normally breaks down proteins (making ulcers worse)
Sucralfate effects
Little absorption from the gut
May cause constipation, nausea, and dry mouth
May impair absorption of other drugs. Give other drugs at least 2 hours before sucralfate.
Do not administer with other medications.
Binds with phosphate; may be used in chronic renal failure to reduce phosphate levels
Misoprostol
Miscellaneous Acid-Controlling Drugs
Prostaglandin E analogue
Prostaglandins have cytoprotective activity.
-Protect gastric mucosa from injury by enhancing local production of mucus or bicarbonate
-Promote local cell regeneration
-Help to maintain mucosal blood flow
Misoprostol is used for?
Used for prevention of NSAID-induced gastric ulcers
Doses that are therapeutic enough to treat duodenal ulcers often produce abdominal cramps and diarrhea.
Simethicone
Miscellaneous Acid-Controlling Drugs
Antiflatulent drug
Used to reduce the discomforts of gastric or intestinal gas (flatulence)
Alters elasticity of mucus-coated gas bubbles, breaking them into smaller ones
Result is decreased gas pain and increased expulsion via mouth or rectum.
Nursing Implications: Antacids
Assess for allergies and pre-existing conditions that may restrict the use of antacids, such as:
-Fluid imbalances
-Renal disease
-Gastrointestinal obstruction
-Heart failure
-Pregnancy
Patients with heart failure or hypertension should not use antacids with high sodium content.
Administer antacids within 1 to 2 hours of other medications.
Antacids may cause premature dissolving of enteric-coated medications, resulting in stomach upset.
Be sure that chewable tablets are chewed thoroughly and that liquid forms are shaken well before giving.
Administer with at least 240 mL of water to enhance absorption (except for “rapid-dissolve” forms).
Long-term self-medication with antacids may mask symptoms of serious underlying diseases, such as malignancy or bleeding ulcers.
Nursing Implications: Antacids Adverse effects
Nausea, vomiting, abdominal pain, diarrhea
With calcium-containing products: constipation, acid rebound
Nursing Implications: H2 Antagonists
Assess for allergies and impaired renal or liver function.
Use with caution in patients who are confused, disoriented, or in older adult patients.
Take 1 to 2 hours before antacids.
For intravenous doses, follow administration guidelines.
Nursing Implications: Proton Pump Inhibitors
Assess for allergies and history of liver disease.
Not all are available for parenteral administration.
May increase serum levels of diazepam and phenytoin; may increase chance for bleeding with warfarin
The granules of ______ capsules may be given via nasogastric tubes
pantoprazole
Capsules may be opened and their contents mixed with apple juice, but delayed-release granules are not to be crushed or chewed.
simethicone
excessive flatus
causes mucus coated gas bubbles to break into smaller ones
H2 receptor antagonist drug interaction
ketoconazole
How to administer sucralfate
give drug on an empty stomach
antacid if pt has kidney problems
aluminum-based antacids
oral tetracycline complains of heartburn and requested antacid
give tetracycline but delay antacid for 1-2 hours
PPI
give on empty stomach
make sure pt does not crush/ chew capsules
1st dose of misoprostol, what is a contraindication?
pregnancy
