252 Pharmacology - Acid Controlling Drugs Flashcards
Which glands of the stomach are the largest in number and of primary importance when discussing acid control?
Gastric glands
What is the function of parietal cells?
- Produce and secrete hydrochloric acid
- Primary site of action for many of the drugs used to treat acid-related disorders
What do chief cells do?
- Secrete pepsinogen, a proenzyme
- Pepsinogen becomes pepsin when activated by exposure to acid.
- Pepsin breaks down proteins (proteolytic).
What are the purposes of mucous cells?
- Mucus-secreting cells (surface epithelial cells)
- Provide a protective mucus coat
- Protect against self-digestion by hydrochloric acid and digestive enzymes
When is hydrochloric acid secreted?
- Secreted by parietal cells when stimulated by food, caffeine, chocolate, and alcohol
- Secretion also stimulated by
- Large fatty meals
- Emotional stress
What pH does HCl keep the stomach at?
Maintains stomach at pH of 1 to 4
What does HCl do?
Acidity aids in the proper digestion of food and defenses against microbial infection via the gastrointestinal tract
What does triple therapy for H. pylori involve?
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.
What are the characteristics of stress-related mucosal damage in hospitalized patients?
- 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.
What are the classes of acid controlling drugs?
- Antacids
- H2 antagonists
- PPIs
How do antacids help with acid controlling?
- 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.
Antacids that may lead to the development of kidney stones and increased gastric acid secretion.
Calcium antacids
What kind of antacid must be avoided in patients with renal failure?
Antacids containing magnesium
Which antacid is a highly soluble antacid form with a quick onset but a short duration of action.
Sodium bicarbonate
What is the mechanism of action of antacids?
- Do not prevent the overproduction of acid but instead help to neutralize acid secretions
- Promote gastric mucosal defensive mechanisms
- Stimulate secretion of:
- Mucus: protective barrier against hydrochloric acid
- Bicarbonate: helps buffer acidic properties of hydrochloric acid
- Prostaglandins: prevent activation of proton pump