Pharm-Antacids/Anti-PUD Flashcards
What 3 things do antacids do?
- neutralize HCl in stomach
- Decrease acid load to duodenum
- Diminish pepsin activity
What SE is associated with sodium bicarb?
metabolic alkalosis
What makes aluminum hydroxide different from other antacids?
Aluminum compounds, in contrast to other antacids, cause slowing of gastric emptying and marked constipation. Used with caution in the elderly.
What effect does magnesium hydroxide have that is different from aluminum hydroxide?
prominent laxative effect (osmotic diarrhea)
What is acid rebound? What antacid is associated with it?
Increased gastric acid secretion several hours after neutralization.
Calcium carbonate-containing antacids evoke hypersecretion of hydrogen ions (acid rebound).
What antacid can cause milk-alkali syndrome? what is it?
Calcium carbonate. Hypercalcemia.
What do H2 blockers do? What is the prototypical example?
inhibits basal acid secretion including nocturnal secretion.
Cimetidine (strong p450 inhibitor)
What do proton pump inhibitors do?
form covalent bond /w proton pump (H+/K+ ATPase) → irreversible inhibition of acid production (long acting b/c need to regenerate pumps)
blocks both basal and stimulated acid secretion.
What is the prototypical PPI?
Omeprazole: (-prazoles)
Pro-drug (needs low pH to activate)
Reduces gastric acid → elevates gastric pH
Why are PPIs better than H2 antagonists?
- No effect on pepsinogen
- no effect on p450
- no serious SE associated w/ high doses
What do Prostaglandins/Mucosal Protective Agents inhibit/stimulate?
Inhibits: Acid secretion, Gastrin release and Pepsin secretion
Stimulates: Mucus secretion, Bicarbonate secretion and Mucosal blood flow
What prostaglandin E1 analog can be used to prevent NSAID-induced gastric ulcers? Why is it not widely used?
Misoprostol
SE: D, GI upset (exacerbates IBD), abortion
b/c multiple daily dosing and SE
What mucosal protective agent forms a sticky polymer that adheres to ulcerative tissue and coats mucosal defects?
Sucralfate (sugar molecule)
What does chelated bismuth (bismuth subsalicylate) do? Why is it important in children?
Protects the ulcer crater and allows healing.
Some activity against H. pylori.
Should not be used repeatedly or for more than 2 months at a time.
Can cause black stools, constipation.
Can color mucosal tissue.
Subsalicylate is clinically important for children recovering from influenza or chicken pox because of the association between salicylates and Reye’s syndrome.
What do antispadmodics do? What do they inhibit? What other drug do they resemble?
A specific anticholinergic effect (antimuscarinic) at the acetylcholine (ACh)-receptor sites.
Competitive inhibitors of muscarinic receptors in the enteric plexus and on smooth muscle.
SE: tachycardia, constipation, hypersensitivity to light, dry mouth, urinary retention, cycloplegia (atropine-like, but don’t cross BBB and are less potent).
