Gastro Pharm Flashcards
Xerostomia Tx
M3»M1, CYP3A3/4 interactions CYP2D6 ; contraindicated in asthma, closed angle glaucoma or iritis (caution w/ cardiac disease change in conduction through the AVN, nephrolithiasis)
(cholingergic bronchial smooth muscle constriction, will cause a change in visual acuity, & difficult w/ vision in transition to darkness
Cevimeline
Xerostomia Tx
All muscarinic receptors, also avoid in psychosis owing to greater CNS activity (as well as contraindications above)
Pilocarpine
Xerostomia Tx
free radical scavenger, given as a nephroprotective agent in cisplatin & to protect salivary glands in the protection during irradiation of the head & neck (can permanently damage the salivary glands)
Amifostine
Magnesium-aluminum hydroxide
balance between constipation by aluminum & diarrhea by magnesium – Mylanta
H2 Antagonist lowest potency (1); inhibits P450 and slows metabolism of many drugs
Cimetidine
H2 Antagonist
middle potency, name 2
Ranitidine
Nizatidine
Strongest H2 Antagonist
Famotidine
(Pepto-Bismal)–enhances secretion of mucus and HCO3, inhibits pepsin activity, chelates w/ proteins at the base of the ulcer crater and forms a protective barrier against acid and pepsin; inhibits H pylori; effective adjunct for tx PUC/ duodenal/ gastric ulcers, diarrhea
Bismuth subsalicylate
forms a sticky, viscous gel that adheres to gastric epithelial cells protecting them from acid and pepsin; only agent in its class that requires an acidic pH for max activity; given 1 hr before meals and at bedtime to promote gastric healing; value in H2 blocker/ PPI induced pneumonia in bedridden patients; alkalinization of stomach reintroduces bacteria to stomach
Sucralfate
PPI
oral, long duration, more powerful than H2 blockers - name 2
Omeprazole
Esomeprazole
PPI, less effective in severe esophagitis
Lansoprazole
PPI, less metabolized by P450
Rebeprazole
Cytoprotective Agent; slowly metabolized analog of PGE1, stimulates mucus and HCO3 production, diarrhea in 40% patients; used in patients who must use NSAIDS
(mostly used for abortion)
Misoprostol
Eradication of H pylori
Clarithromycin – macrolide, inhibits protein synthesis
Metronidazole –active against obligate anaerobes (more primary resistance 43%)
Tetracycline - second line for pt allergic to penicillin; stagger dose when given w/ bismuth; least primary resistance (<1%)
Amoxicillin- Effective against Gram Negative bacilli (resistance 3%)
Furazolidine – Nitrofuran antibacterial& antiprotozoal
Enhances gastric motility, improves LES tone) - prokinetic agents
only Rx approved for gastroparesis
sensitization of smooth muscle muscarinic receptors
DA receptor blocker, serotonin blocker –> antiemetic effects
tardive dyskinesia
stimulates GI smooth muscle. Increases amplitude of esophageal contractions, accelerates gastric emptying, increases LES pressure (main anti-reflux is enhanced gastric emptying)
local dopamine blocker (not FDA approved in US, but patients can purchase medicine from Canda); tx for gastroparesis
Domperidone
partial 5HT-4 agonist (selective serotonin agonist), short-term tx of constipative IBS (increased rate of stroke, heart attack & worsening heart-related chest pain)
Tegaserod
treatment of IBD: control inflammation, reduce morbidity, prevent complications, nutrition; given as enteric tablet, broken down by intestinal bacteria to sulfapyridine (causes SE anemia, rash, importence) & 5-aminosalicyclic acid (5-ASA acts like a local anti-inflammatory agent)
Sulfasalazine
monoclonal Ab against TNF-alpha; IV for Crohn’s; given with immunosuppressive therapy
Infliximab
inhibits integrins from binding to intestinal lining
Natalizumab
semisynthetic disaccharide; metabolized by enteric bacteria to organic acids such as lactic, formic, acetic acid – a fecal acidifier; acidification of the stool retards nonionic diffusion of ammonia from the colon to the blood because NG3 is the ammonium form which is non-diffusable; sinch lactulose is not absorbed, it produces an osmotic laxative effect
Lactulose
Ribavirin, Telaprevir, Boceprevir, Peginterferon-a-2b
Hep C
Tenofovir, entecavir, telbivudine, adefovir, lamivudine, emtricitabine
Hep B
Lamivudine, Telbivudine class
L-nucleoside - Hep B
Adefovir, Tenofovir
Acyclic Phosphonates - Hep B
Entecavir
D-cyclopentane - Hep B
nucleotide analog of adenosince 5 monophosphate; diphosphate form inhibits polymerase and terminates chain
Taken with high fat
AE: ARF, avoid NSAIDs, ask about bone pain
Patients predisposed dysfunction in apical pump so that drug cannot be extruded into lumen/ urine (increased renal toxicity) – OAT1 KOs have proximal tubule accumulation
Bone pain?
active against HIV and HBV
Tenofovir
Guanosine nucleoside analog
food delays absorption
Entecavir
L-isomer of thymidine
food- no effect
Telbivudine
Adenosine-5 monophosphate - chain termination in diphosphate form
Adefovir
L-isomers of cytosine; triphosphate form inhibits HBV
food - no effect
Lamivudine
Emtricitabine
Serine protease inhibitors for Hep C-1
bind plasma proteins, take them with food, undergo hepatic metabolism, eliminated in stool
Telaprevir
Boceprevir
First line for Hep C
high fat meal is beneficial for distribution;
enhanced host T cell function,
inhibition of host inodine monophosphate dehydrogenase (IMPDH) w/ depletion of guanosine triphosphate, essential for viral RNA synthesis
direct inhibition of RNA-dep RNA polymerase, may only transiently reduce HCV RNA but will normalize ALT
synergistic w/ interferon
Primary toxicity: hemolytic anemia (10-13%), extensive uptake into cells (indlucing erythrocytes), no CYP action, renal elimination; available as inhalation product
Ribivirin
Serine protease for HepC1 that can cause rash & inhibits CYP3A4
Telapravir
