Flashcards in GI pharmacology Deck (16)
Name 3 Histamine-2 (H2) receptor antagonists.
1) Cimetidine (Tagamet)
2) Ranitidine (Zantac)
3) Famotidine (Pepcid)
What is the MOA of H2 receptor antagonists?
antagonism of gastric H2 receptors inhibits hydrochloric acid production and raises gastric pH
What are the drug interaction concerns with Cimetidine (Tagamet)?
inhibits CYP450 enzymes found on hepatic microsomes, thereby interfering with its normal function of metabolizing drugs
-prolongs action of drugs that are metabolized by the liver--> theophylline, coumadin, warfarin, aminophylline, phenytoin, halothane, lidocaine, phenobarbital, diazepam, propanolol, labetalol, meperidine, quinidine, TCAs (imipramine and desipramine), and calcium channel blockers
What is special about ranitidine in comparison to cimetidine in regards to side effects?
does not traverse the BBB effectively, so it causes less somnolence, lethargy, confusion, hallucinations, and seizures than cimetidine
Why are non-particulate antacids preferred over particulate antacids?
b\c they cause less problems than particulate antacids if aspirated
What drug helps to control gastric motility?
What are the actions of metoclopramide (Reglan)?
-increase LES tone (prevents reflux into the esophagus)
-increase gastric motility (promotes gastric emptying)
-decrease in tone of pyloric sphincter (permits passage of foodstuffs from the stomach to the small intestine)
-relaxation of the duodenum (this makes room for food coming from the stomach)
How does metoclopramide effects gastric pH?
it has No effect on gastric pH
Incidence and severity of aspiration pneumonitis are reduced if:
gastric pH is > ______.
gastric volume is < ______.
pH above 2.5
volume < 25mL (0.4ml/kg)
Histamine-2 antagonists reduce ________ ________ ______ secretion, and this action increases gastric pH and decreases gastric volume.
gastric hydrochloric acid
________ decreases gastric volume without altering pH.
What 3 drugs are competitive dopamine antagonists?
1) droperidol (Inapsine)
2) prochlorperazine (Compazine)
3) metoclopramide (Reglan)
Why should droperidol be avoided in the Parkinsons patient?
b\c of its dopamine receptor antagonist activity
Which antimuscarinic is used as an antiemetic?
Name a selective serotonin-3 antagonist.
ondansetron (Zofran)--> 5HT3 antagonist