GI Flashcards
Amoxicillin
-Preferred component due to low resistance/toxicity
Clarithromycin
-Increasing resistance
Metronidazole
-alternative for patients allergic to penicllin
Tetracycline
-Used in Bismuth-base quadruple therapy
Bismuth Subsalicylate
-Colloidal therapy where salicylate is absorbed in the stomach and bismuth is secreted in feces
-MOA:
-antibacterial activity of bismuth against H. Pylori and E. coli enterotoxins,
-Forms barrier that protects ulcers from further damage
-anti-secretory and anti-inflammatory salicyclate
Therapy:
-PUD
-Diarrhea: inhibition of intestinal prostaglandin and chloride secretion
-Adverse effects:
-Reyes and salicylism
Magnesium Hydroxide Aluminum hydroxide
- MOA:
- Alkaline compounds that neutralize gastric acid and raise stomach pH, most raise to pH of 5
- Pharm:
- Rapid onset with shot duration of action
- Mg can cause diarrhea due to stimulation of peristaltic activity but Al counteracts this effect
- Ions aren’t well absorbed so don’t cause metabolic alkalosis
- Uses:
- relief of mild symptoms of dyspepsia and GERD
- Can interfere with absorption of other drugs (2hr window)
Cimetidine
MOA: Competitive inhibitor of H2 on basolateral mem of parietal cells –> decreased Gastrin and ACh respons, slower onset than antacids but longer duration (prophylaxis)
USES:
-PUD: Short term promotes healing by decreasing nocturnal acidity
-GERD: Best for nocturnal modest post prandially
-Aspiration Pneumonitis: during anesthesia
Adverse RXN:
-ENDO: blocks androgen receptors –> gynecomastia, impotence, and loss of libido
-CNS: Elderly
-Pneumonia: Incr. bac colonization due to lower pH
Omeprazole (PPI)
- MOA: activated within parietal cells and blocks H/K ATPase, final common pathway for basal and stimulated acid release, effects last until new ATPase are generated
- Pharm: enteric coated, can react with 2C19 (Asians) and dose reduction with hepatic disease
- Uses: PUD and Gerd, Zollinger Ellison, NSAID ulcers in people who continue to use NSAIDS
- ADVERSE: Interactions with, Warfarin, Diazepam, cyclosporine, C. Diff, bone fractures, rebound hyper secretion
Sucralfate
- Sulfated sucrose and AlOH
- MOA: Gel at pH 4 and binds necrotic tissue to form a barrier, take on empty stomach
- USES: Duodenal and stress ulcers, no risk of nosocomial infx
- Adverse: Reduced absorption of other drugs
Misoprostol
- Prostaglandin analog
- MOA: substitutes for PGs when synthesis is inhibited by NSAIDS, reduces acid secretion from parietal cells and promotes bicarb and mucus secretion
- USES: Prevention of gastric ulcers in long term NSAID therapy, NOT PREGNANCY!!!!!!!!!!!
Psyllium
- Bulk forming (group III)
- MOA: Non-digestable agents that swell with H2O increases volume of stool and stim. peristalsis
- Uses: Temp treatment of mild constipation
- Must BE ADMINISTERED WITH A FULL GLASS OF H2O
Docusate Sodium
- Surfactant (Group III)
- MOA: Lowers surface tension allows penetration of H2O
- Uses: Mild Constipation, take with full glass of H2O
Bisacodyl
-Stimulant (group II)
-MOA: Stimulate (via irratation) GI motility and increase H2O and electrolytes within the lumen. (ORAL or ANAL)
-USES: Opioid induced constipation and constipation from slow intestinal transit
ADVERSE: Proctitis with long term use
Magnesium Hydroxide
-Osmotic laxative (Group I)
-MOA: Poorly absorbed salts or sugars which draw H2O in to the stool
USES:
-High Dose: Colonoscopy
-Low Dose: Mild to moderate constipation
-Purging to remove dead parasites
-Adverse RXN: Dehydration and electrolyte imbalance also Mg absorbtion may cause problems with people who have renal impairment
Lactulose
-Prevent hepatic encephalopathy by turning NH3 –> NH4 and trapping it in the stool
Loperamide and Diphenoxylate
-MOA: Agonists for myenteric opiate receptors that reduces secretory activity (delta) and GI motility (Mu)
-PK:
-Loperamide: Poor BBB penetration no abuse
-Diphenoxylate: High oral doses can produce morphine like responses (atropine)
Adverse Effects: Constipation with prolonged use, methylnaltrexone used to treat opiate induced constipation
Ondansetron
- MOA:5HT3 antagonists at peripheral and central site (most effective but efficacy enhanced by corticosteroids)
- PK: Administered IV, long duration of action
- USES: prevent or minimize emesis form CINV and radiation, hyperemesis of pregnancy, NOT effective against motion sickness or DELAYED CINV
Aprepitant
- Blocks NK1 receptors in brain
- Uses: Delayed nausea cisplatin, improves efficacy of other CINV treatments
Black Cohosh
-USE: Treat menopause and PMS
-Active ingredients: Triterpene glycosides and isoflavones (not related to female hormones)
-Efficacy: Probably not (no difference from placebos and inferior to estrogen)
AE: Liver toxicity
Drug Interactions: Potentiates antihypertensives and Oral diabetic medicines
-Avoid during pregnancy and in patients with breast cancer (blue cohosh stimulates uterine contractions
Echinacea
- Use stimulate immune function (URI)
- Active ingredients: echinacosides, polysaccharides, flavonoids
- MOA: INVITRO stimulation of Macrophage activity and t-lymphocyte proliferation but RCT no difference from placebos in treatment and no prevention
- Drug interactions/Contraindications: immunosuppressants, autoimmune disorders
Garlic
- Use: Cholesterol and HTN
- Active ingredient: Organic sulfur compounds, alliin -> allicin (enteric coated)
- MOA: In vitro inhibition of HMG-CoA and reduces platelet aggregation
- Efficacy: May have modest effect but RCT showed no difference in patients with mild hypercholesterolemia but mild blood pressure lowering
- Drug interaction: Aspirin/anticoagulants, insulin/OHAS, saquinivir (incr. clearance)
GInkgo
- USE: Improve memory and concentration, vascular problems
- Active ingredients: flavonoid glycosides
- MOA: increase blood flow to CNS (vasodil.), free radical scavenger, suppresses synth of platelet activating factor
- Efficacy: no difference from placebo in AD and cog decline, RCT showed effects similar to exercise
- Adverse effects: Seeds are epileptogenic
- Drug interactions: Anticoagulants
Ginseng
Use: Tonic to enhance athletic performance
- Active ingredients: ginsenosides
- Efficacy: NOT
- Adverse Effects: Weak estrogenic effects
- Interactions: anticoagulants and insulin/OHA
Ma Huang (ephedra)
-Use Reduce appetite and increase energy, narcolepsy, and nasal congestion
-Active ingredient ephendrine (release of NE)
Efficacy: Well established
Adverse effects” Excessive CNS and CV stimulation
Drug Interactions: CNS stimulants Beta agonist, nasal decongestants, MAOIs, Antihypertensives
Kava
Use: anxiety and promote sleep
Active: Alpha pyrones or lactonoes
Efficacy: anxiolytic and muscle relaxant good evidence
Adverse effects: CNS depresses and abuse potential, severe liver damage
Drug interactions: Potentiate other CNS depressants (bentos, barbituates, opiod)
St. Johns Wort
USE: relieve depression
Active ingredient: hyperforin
Efficacy: good evidence in mild to mod depression RCT no difference in mod to severe depression
Adverse: Some allergic RXNS, photo sensitivity, and Mania
Drug Interactions: Induction of CYP 3A4 and P-glycoprotein and serotonin syndrome with SSRIs
Saw Palmetto
- Relieve BPH symptoms
- Active ingredient isn’t know, but extract is anti-androgenic
- Efficacy RCT no difference from placebo for BPH
- Adverse effects: Well-tolerated, may reduce PSA (no pregnant females
- Drug interactions with finasteride
Acid or Base ingestions
Don’t neutralize (excess heat), dilute with H2O
Activated Charcol
- Inert rapidly and irreversibly absorbs drugs and other organic compounds
- Give in Slurry of H2O within 60 mins.
- Adverse effects: Aspiration
Syrup of Ipecac
-NOT RECOMMENDED TO BE USED
Enhancement of Elimination
- Urinary arlkalinization (weak organic acids) or acidification (weak bases) substances MUST BE ELIMINATED BY KIDNEY.
- Hemodialysis
Methylene Blue
- Used to treat methylhemaglobinemia
- Slowly infused
- May cause serotonin syndrome in Pts taking SSRIs b/c it inhibits MAOs
- DONT GIVE TO PEOPLE WITH G6PD
- Can turn urine bluish green
Intermittent Porphyria
- Abnormal regulation of heme synthesis –> abnormal accumulation of heme precursors due to deficiency of porphobilinogen deaminase
- SX: ab pain, peripheral neuropathy, mental dysfunction
- Induced by drugs that increase rate of heme synthesis (induce CYP450) –> accumulation of toxic heme precursors
TX of Intermittent Porphyria
- Withdraw precipitating drug and confirm diagnosis
- Hematin inhibits ALA synthetase
Carbon Monoxide
- Combines with ferrous iron of hemoglobin with a 201 fold greater affinity –> Hypoxia
- Long term affects: Parkinsonism, amnesia, cortical blindness, inhibition of iron containing proteins, NO like effects, may lead to hypoxia-reperfusion injury in CNS
- TX: get away from CO and give O2
Cyanide
- HCN gas, NaCN, cyanogenic glycosides (seed), some people can smell
- Combines with ferric iron to inactivated cytochrome oxidase and inhibit cellular respiration (onset hints at source)
Cyanide treatment
- Hydroxycombalamin: binds CN and forms a stable complex excreted in urine (reddish color of skin, membranes, and urine)
- Sodium Nitrite: convert hemoglobin to methemoglobin which causes dissociation of CN from Cytochrome oxidase
- excessive methemoglobinemia (methylene blue) excessive vasodilation causing hypotension
- Sodium Thiosulfate: rhodanese catalyzed conversion of CN to thiocyanate which is excreted in the urine
Chelation
- formation of coordination complexes of metal ions with organic ring systems to prevent the free metal from causing toxicity, promotes urinary or biliary excretion of the metal
- High affinity for the toxic metal and low affinity for the endogenous (CA,Mg,Zn) must reach sites of deposition, and from a chelates that are less toxic than free metal and are easily excreted
Dimercaptol
- Pb, As, Hg
- Major use is in combo with EDTA fro severe Pb intoxication
- Must be given IM and urine must be kept basic to prevent renal damage
- Side effects:
- Diphenhydramine to prevent histamine related side effects
- Nausea and vomiting/ pain at injection site
- Hemolytic Anemia in G6PD
Succimer
- chelates Pb in children
- Pill
- prevents seizures and fatalities from Pb encephalopathy
- doesnt reduce long term neuro effects
Ca disodium EDTA
- Chelates Pb and Ca
- Ca salt must be given to prevent tetany
- IV or IM
- Given after BAL for initial treatment of severe Pb intoxication (can increase intracranial pressure if given to pts with Pb encephalopathy) used alone for moderate Pb
- Renal tubular necrosis
Deferoxamine
- Fe chelator
- strip Fe bound to ferritin and hemosiderin but doesn’t affect Fe bound to hemoglobin or cytochrome
- excreted in Urine and bile
- acute iron poisoning or pts with thalessemias
- IV or SC (overnight for chronic overload)
- Hypotension of admin is too rapid (IV)
- ARDS when given IV for long periods
- Long term use may –> visual and auditory loss and increased risk of infx
