Gastrointestinal Drugs Flashcards
Sodium bicarbonate (NaHCO3)
Antacid
Duration: 1-2 hrs
Rate of reactivity: fast
Common adverse effects: reduced drug bioavailability, enteric infection
Specific adverse effects: metabolic alkalosis, excessive NaCl absorption, gas/bloating
Clinical use: GERD, peptic ulcers, dyspepsia
Equally efficacious to H2-receptor antagonists
Adjunctive therapy
Calcium carbonate (CaCO3)
Antacid
Duration: 1-2 hrs
Rate of reactivity: moderate
Common adverse effects: reduced drug bioavailability, enteric infection
Specific adverse effects: acid rebound, gas/bloating, hypercalcemia (large doses), hypophosphatemia (rare)
Clinical use: GERD, peptic ulcers, dyspepsia
Equally efficacious to H2-receptor antagonists
Adjunctive therapy
Magnesium hydroxide (Mg(OH)2)
Antacid
Duration: 1-2 hrs
Rate of reactivity: slow
Common adverse effects: reduced drug bioavailability, enteric infection
Specific adverse effects: osmotic diarrhea, hypermagnesemia (large doses over extended periods of time)
Clinical use: GERD, peptic ulcers, dyspepsia
Equally efficacious to H2-receptor antagonists
Adjunctive therapy
Aluminium hydroxide (Al(OH)2)
Antacid
Duration: 1-2 hrs
Rate of reactivity: slow
Common adverse effects: reduced drug bioavailability, enteric infection
Specific adverse effects: constipation, aluminum toxicity (impaired renal function), hypophosphatemia, bone resorption, hypercalcemia
Clinical use: GERD, peptic ulcers, dyspepsia
Equally efficacious to H2-receptor antagonists
Adjunctive therapy
cimetidine (Tagemet)
ranitidine (Zantac)
nizatidine (Axid)
famotidine (Pepcid)
H2-receptor antagonist: competitive inhibition of histamine, partial block of muscarinic-induced HCl secretion
Duration: 10hrs or 6 hrs OTC
Common adverse effects: headache, diarrhea, fatigue, constipation, infection, drug kinetics, bradycardia (IV), hypotension (IV)
Cimetidine specific considerations: CNS effects( confusion, hallucinations, agitation), endocrine effects (inhibits androgen receptors and estradiol metabolism—>gynecomastia, increases prolactin levels), inhibits hepatic CYP metabolism
Clinical use: GERD, peptic ulcers, dyspepsia, gastritis
Equally efficacious to anacids
Omeprazole (Prilosec) Lansoprazole (Prevacid) Rabeprazole (Aciphex) Esomeprazole (Nexium) Pantoprazole (Protonix)
Proton pump inhibitors (PPIs): low pH activated, irreversibly binds and inhibits proton bump
Duration of action: 24 hrs, takes 3-4 days of dosing to reach max effect
Common adverse effects: extremely safe, decreased drug bioavailability, diarrhea, headache, abdominal pain
Adverse effects: decreased nutritional absorption (Vitamin B12, iron, calcium, zinc), enteric & respiratory infection
Clinical use: GERD, peptic ulcers, dyspepsia, gastritis, hypersecretory diseases, NSAID-associated ulcers, H. pylori associated ulcers
Most efficacious inhibitors of acid secretion
Sucralfate (Carafate)
Mucosal protective agent
Mechanism: adheres to ulcer and creates physical barrier; stimulates mucus secretion (PGEs?)
Duration of action: 6 hrs
Common adverse effects: constipation, impaired drug absorption
Adverse effects: caution w/ renal insufficient patients
Clinical use: prevent stress-related bleeding when you do not want to prevent acid secretion (hospitalized patient–>infection)
Bismuth subsalicylate (Pepto-Bismol)
Mucosal protective agent
Mucosal protective agent
Mechanism: adheres to ulcer and creates physical barrier; stimulates mucus secretion (PGEs?)
Mucosal protective agent
Mechanism: adheres to ulcer and creates physical barrier; stimulates mucus secretion (PGEs?)
Duration of action: 6 hrs
Common adverse effects: constipation, impaired drug absorption
Adverse effects: caution w/ renal insufficient patients
Clinical use: H. pylori associated ulcers, travelers diarrhea, dyspepsia
Misoprostol (Cytotec)
Mucosal protective agent
Mechanism: PGE analogue stimulating mucus and bicarb secretion
Duration of action: 6 hrs
Common adverse effects: cramping, diarrhea
Adverse effects: abortificient (stimulates uterus contractions)
Clinical use: NSAID associated ulcers
H. pylori & gastric ulcer Tx
“new triple therapy”: PPI, clarithromycin, amoxicillin or metronidazole
“old triple therapy”: bismuth subsalicylate, tetracycline, metronidazole
“quadruple therapy”: bismuth subsalicylate, PPI, clarithromycin, amoxicillin or metronidazole
Metoclopramide (Reglan)
Prokinetic agent
Mechanism of action: D2 antagonist
Clinical use: GERD, impaired gastric emptying, dyspepsia, antiemetic
Adverse effects: CNS (restlessness, drowsiness, insomnia, anxiety); altered motor function (Parkinsonian symptoms)
Bethanechol (Urecholine
Prokinetic agent
Mechanism of action: M3 agonist
Clinical use: GERD, gastroparesis
Adverse effects: cholinergic side effects
Neostigmine (Prostigmin)
Prokinetic agent
Mechanism of action: AChE inhibitor
Clinical use: non-obstructive (urinary retention, abdominal distension)
Adverse effects: cholinergic side effects
Erythromycin (Erythrocin)
Prokinetic agent
Mechanism of action: Motilin receptor agonist
Clinical use: gastroparesis
Adverse effects: acute cholestatic hepatitis, jaundice
Methylcellulose (Citrucel)
Laxative: bulk-forming
Mechanism of action: fiber adds bulk and retains water
Absorption: poor
Clinical use: constipation, minimize straining, prior to surgical and endoscopic procedures
Adverse effect: gas/bloating
Glycerin (Colace)
Laxative: surfactant
Mechanism of action: coats and penetrates fecal material
Absorption: poor
Clinical use: constipation, minimize straining, prior to surgical and endoscopic procedures
Adverse effect: nutrient malabsorption
Lactulose (Enulose)
Laxative: osmotic
Mechanism of action: changes osmotic pressure
Absorption: poor
Clinical use: constipation, minimize straining, prior to surgical and endoscopic procedures
Adverse effect: gas, electrolyte flux
Senna (Ex-Lax
Laxative: stimulant Mechanism of action: stimulate ENS Absorption: poor Clinical use: constipation, minimize straining, prior to surgical and endoscopic procedures Adverse effect: GI irritation
Tegaserod (Zelnorm)
Laxative: serotonin agonist
Mechanism of action: 5-HT4 partial agonist
Absorption: 10%
Clinical use: chronic idopathic constipation
Adverse effect: GI, CV, NOT available for general use
Lubiprostone (Amitize)
Laxative: chloride channel activator
Mechanism of action: prostaglandin derivative
Absorption: poor
Clinical use: chronic constipation
Adverse effect: nausea/vomiting, diarrhea
Methylnaltrexone (Relistor)
Laxative: Mu-opioid receptor
Mechanism of action: block peripheral mu-opioid receptors
Absorption: poor CNS penetration
Clinical use: opioid-induced constipation during palliative care
Adverse effect: abdominal pain, flatulence, nausea, diarrhea
Alvimopan (Entereg)
Laxative: Mu-opioid receptor
Mechanism of action: block peripheral mu-opioid receptors
Absorption: poor CNS penetration
Clinical use: postoperative ileus in hospitalized pts w/ bowel resection
Adverse effect: abdominal pain, flatulence, nausea, diarrhea, MI (so use for only 7 days)
Loperamide (Imodium)
Antidiarrheal agents
Mechanism of action: opioid agonist
Clinical use: diarrhea (IBS)
Adverse effects: constipation (very safe)
Diphenoxylate (Lomotil)
Antidiarrheal agents
Mechanism of action: opioid agonist
Clinical use: diarrhea
Adverse effects: CNS effects, atropine effects
Bismuth subsalicylate (Pepto-Bismol)
Antidiarrheal agents
Mechanism of action: inhibit PG synthesis (intestinal), absorb toxins
Clinical use: non-specific diarrhea, travelers diarrhea
Adverse effects: salicylate toxicity
Cholestyramine (Prevalite)
Antidiarrheal agents
Mechanism of action: bind bile acids and salts
Clinical use: impaired bile-salt absorption mediated diarrhea
Adverse effects: bloating, flatus, constipation, fecal impaction, impaired fat absorption
Octreotide (Sandostatin)
Antidiarrheal agents
Mechanism of action: Somatostatin receptor agonist
Clinical use: secretory diarrhea (severe cases)
Adverse effects: impaired pancreatic secretion, decreased GI motility (nausea, pain), decreased gall bladder contraction, glucose homeostasis
Ondansetron (Zofran)
Antiemetic agents (direct regulator) Mechanism: 5-HT3 antagonist Clinical use: chemotherapy, postoperative, postradiation Adverse effects: headache, dizziness, constipation, prolonged QT interval
Scopolamine (Transderm Scop)
Antiemetic agents (direct regulator)
Mechanism: M1 antagonist
Clinical use: motion sickness
Adverse effects: antimuscarinic effects
Metoclopramide (Octamide)
Antiemetic agents (direct regulator)
Mechanism: D2 antagonist
Clinical use: chemo & radiation therapy induced nausea and vomiting
Adverse effects: extrapyramidal (Parkinsonian symptoms)
Dimenhydrinate (Dramamine)
Antiemetic agents (direct regulator)
Mechanism: H1 antagonist
Clinical use: motion sickness
Adverse effects: drowsiness
Aprepitant (Emend)
Antiemetic agents (direct regulator) Mechanism: NK1 antagonist Clinical use: chemotherapy Adverse effects: fatigue, dizziness, diarrhea, CYP3A4 interactions
Prochlorperazine (Compro)
Antiemetic agents (direct regulator)
Mechanism: M1 D2 H1 antagonist
Clinical use: severe nausea/vomiting
Adverse effects: extrapyramidal, drowsiness, anticholinergic
Lorazepam (Ativan)
Antiemetic agents (indirect regulator)
Mechanism: GABA agonist
Clinical use: anxiety/chemotherapy
Adverse effects: drowsiness
Nabilone (Cesamet)
Antiemetic agents (indirect regulator)
Mechanism: Cannabinoid agonist
Clinical use: chemotherapy
Adverse effects: dysphoria, sedation, increased appetite
Dexamethasone
Antiemetic agents (indirect regulator)
Mechanism: Glucocorticoid agonist
Clinical use: chemotherapy, postoperative (increase effectiveness of 5-HT antagonists)
Adverse effects: weight gain, water retention, other corticosteroid effects
Alosetron (Lotrenex)
Tx for IBS
Mechanism of action:5HT3 antagonist–>block visceral pain, motility, and secretions
Clinical use: IBS diarrhea (women)
Adverse effect: constipation, ischemic colitis (fatal)
Last resort drug
Azathioprine (Azoson)
6-mercaptopurine
Antimetabolite
Mechanism: inhibits purine synthesis resulting in decreased DNA synthesis and repair–> decreased cell proliferation (inhibit immune system)
Administration: IM, SC, oral
Clinical use: maintenance of remission of IBD (onset 17 wks)
Adverse effects: nausea, vomiting, bone marrow suppression
Infliximab (Remicade)
Anti-TNFalpha therapy
Mechanism: TNF-alpha monoclonal antibody–>bind/sequester TNF-alpha–>inhibit immune response
Clinical use: moderate to severe IBD
Adverse effects: infection
Mesalamine (Pentosa)
Aminosalicyclates: 5-aminosalicylic acid (5-ASA)
Mechanism: inhibit COX production of PGs, interfere with inflammatory cytokine production, inhibit NF-kappaB signaling
Administration: oral
Target: throughout intestine
Modification: time release microgranules, pH sensitive resin
Clinical use: 1st line agent for mild to moderate ulcerative colitis
Must reach lesion sight, does NOT work if absorbed systemically
Adverse effects: headache, dizziness, abdominal pain
Methotrexate (Rheumatrex)
Antimetabolite
Mechanism: inhibits DHFR resulting in impaired cellular proliferation
Administration: IM, SC, oral
Clinical use: maintenance of remission of Crohn’s (onset 8-12 wks)
Adverse effects: low dose side effects uncommon, but include bone marrow depression and megaloblastic anemia
Prednisone (Predone)
Prednisolone
Hydrocortisone
Budesonide
Glucocorticoids
Mechanism: suppression of inflammatory cytokines (TNF-alpha, IL-1); suppresion of chemokines (IL-8); suppression of adhesion molecules; suppression of signal transduction molecules that mediate cytokine and chemokine activities (NOS, PLA2, COX2, NF-kappaB)
Administration: IV, oral, suppository
Clinical use: moderate to severe active IBD
Adverse effect: glucocorticoid adverse effects
Sulfasalazine (Azulfidine)
Balsalazide
Olsalazine
Aminosalicyclates: 5-aminosalicylic acid (5-ASA)
Mechanism: inhibit COX production of PGs, interfere with inflammatory cytokine production, inhibit NF-kappaB signaling
Administration: oral
Target: colon
Modification: Azo bond linked
Clinical use: 1st line agent for mild to moderate ulcerative colitis
Must reach lesion sight, does NOT work if absorbed systemically
Adverse effects: nausea, GI upset, headache, arthralgia, myalgia, bone marrow suppression, malaise (40% pts can’t tolerate)
Tegaserod
Tx for IBS
Mechanism of action: 5HT4 partial agonist–> increase motility, decrease firing to CNS (block pain)
Clinical use: IBS constipation
Adverse effect: GI pain, dyspepsia, flatulence, nausea/vomiting, diarrhea, CV (MI & stroke)
NOT fro general use
