Gastrointestinal drugs Flashcards
1
Q
Antacids
A
- Bases that neutralizes protons
- Magnesium hydroxide and Aluminium hydroxide; not absorbed from gut
- Mg(OH)2; strong laxative effect
- Al(OH)3; constipating effect
- Calcium carbonate; absorbed from gut, systemic effects, less popular
2
Q
Sucralfate
A
- Plymerizes in the acid environment of the stomach, requires therefor acid pH
- Binds to injured tissue and froms a protective coating over ulcer beds
- Accelerate the healing of peptic ulcers and reduce the recurrence rate
- Must be taken 4 times daily
3
Q
Proton Pump Inhibitors (PPI)
A
- Omeprazole, Esomeprazole, Lansoprazole, Pantoprazole, Rabeprazole
- Is converted to sulfonamides in the parietal cell canaliculi
- React covalently with the H+/K+ ATPase and irreversible inactivate the enzyme
- Rapidly metabolized in the liver
- Effective in PUD associated with H. pylori and with NSAID treatment
- Useful in treatment of Zollinger-Ellison syndrome and of GERD
- Side effects; headache, diarrhea, abdominal pain
- May decrease the oral bioavailability of vit. B12 and certain drugs
- Inhibitors of P450
4
Q
Antibiotics used to treat PUD
A
- To eradicate H. pylori
1) PPI + Bismuth, Tetracyclin and Metronidazole
2) PPI + Amoxicillin and Clarithromycin
5
Q
Misoprostol
A
- PGE1 analog
- Cytoprotective
- Increase mucus and bicarbonate secretion
- Decrease HCl secretion
- Used to prevent NSAIDs-induced ulcers
- Increase uterine contraction; contraindicated during pregnancy
6
Q
Drugs that promote upper GI motility
A
- Stimulate motility in gastroparesis via cholinergic stimulation
- Metoclopramide; acts as an ACh facilitator and dopamine receptor antagonist in the ENS
- Cisapride; act as a 5-HT4 agonist in the ENS facilitating the release of ACh from cholinergic nerve endings
- Side effects: Parkinsonism and extrapyramidal effects (Metoclopramide). Long QT syndrome and fatal arrhythmias (Cisapride)
7
Q
Antiemetics
A
- Metoclopramide
- Dexamethasone
- Some H1 antihistamines (Diphenhydramine, Meclizine, Promethazine)
- Phenothiazines (dopamine antagonists)
- 5-HT3 inhibitors (Ondansetron, Granisetron, Dolasetron)
- Dronabinol (cannabinoid)
- Muscarinic antagonists (Scopolamine)
- NK-1 receptor blocker (Aprepitant)
8
Q
Pancrelipase
A
- Used in abnormality of fat absorption
- Obtained from pigs
- Is inactivated at a pH below 4,0; thus, up to 90% of administered dose will be destroyed in the stomach
9
Q
Treatment of acute pancreatitis
A
- Insulin if hyperglycemia occurs
- Analgesia with strong opioid drugs (peptidine)
- Broad-spectrum antibiotics (Piperacillin. Tetracyclines and Ampicillin is contraindicated)
- PPI or H2 receptor blockers
- Inhibiton of GI hormone secretion (Ocreotide)
10
Q
Laxatives
A
- Irritants: Castor oil, Cascara, Senna, Phenolphthalein
- Bulk-forming: Saline (Mg(OH)2), Osmotic laxatives (Polyethylene, Glycol, Lactulose)
- Stool-softening: Dioctyl sodium sulfosuccinate (Docusate)
- Lubricating: Mineral oil, Glycerin
- Chloride-channel activators: Lubiprostone
11
Q
Antidiarrheals
A
- Diphenoxylate and Loperamide: antimotility properties. Activate opioid receptors in the ENS to inhibit ACh release and decrease peristalsis
- Difenoxid
- Aluminium hydroxide, Methylcellulose: adsorbents
Octreotide, Lanreotide, Vapreotide: Somatostatine analogs, inhibit secretion of GI hormons and constrict arterioles in GI tract
12
Q
Drugs that inhibit the formation of gallstones
A
- Chenodiol: reduce the secretion of bile acids by the liver
- Ursodiol: unknown mechanism
13
Q
Drugs used in inflammatory bowel disease
A
- Glucocorticoids
- Immunosuppressive antimetabolites (e.g., Azathioprine, 6-mercaptopurine, Methotrexate)
- Anti TNF-alpha agents (Infliximab, Etanercept
- Aminosalicylates (e.g., Sulfasalazine, Balsalazide, Mesalamine): release 5-aminosalicylic acid (5-ASA) in the large intestine, which inhibits synthesis of PG and LT
- Antibiotics (Metronidazole, Ciprofloxacine)
14
Q
H2-receptor antagonists
A
- Cimetidine, Ranitidine, Famotidine, Nizatidine
- Competitively block the binding of histamine to H2 receptors, reduce the intracellular concentrations of cAMP and, thereby, secretion of gastric acid
- Used in PUD, especially duodenal, GERD, Zollinger-Ellison syndrome
- Cimetidine inhibit P450
15
Q
Muscarinic M1 receptor antagonist
A
- Pirenzepine, Telenzepine
- Block of M1 receptors on neural cells and diminish neural phase of acid secretion
- Not important in modern therapy of PUD
