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Flashcards in Pharm: Secretion Disorders Deck (14)
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1

Dyspepsia

  • Upset stomach
  • alleviated by reducing gastric acid
  • GERD
  • Peptic Ulcer Disease
    • gastric and duodenal
    • stress-induced

2

Antacids

  • Neutralize gastric acid
    • inhibit pepsin activity
  • Acid+weak base=Salt + H2O

3

Examples of Antacids

  • Sodium Bicarbonate
    • Baking Soda
    • Produces :NaCl, H2O, Co2=Belching
    • Bicarbonate is absorbed 
      • alkinalization-increased excrtion of weak acids
  • Calcium Carbonate
    • TUMs
    • carbonate is absorbed
    • contains calcium: 
      • wantedl-osteoporosis
      • unwanted
        • increased MI risk
        • Kidney stones
    • Hypercalcemia with excessie use
  • Aluminium Hydroxide
    • No CO2-No belching
    • Constipation
  • Magnesium Hydroxide
    • No CO2-No belching
    • Diarrhea
  • Combined: Magnesium/Aluminum hydroxide
    • no gas and belching
  • FEWER absorption problems with hydroxide=less alkalinzation

4

Antacids: Concerns

  • No safety concerrns 
  • but ALTERED absorption and excretion of otehr drugs
    • slowed disoolution of tablets and capsules
    • adsorption and chelation may slow absortiopn 
    • alkalinzation of urine increases acid excretion
    • Recommend: seperate doses of antacids and other drugs by 2 hours
  • w/impaired renal function
    • decreased excretion of absorbed metals
  • Patients consider them not a drug

5

H2 Antagonists

  • Reversible 
  • "tidine" family
    • Cime
    • rani
    • Ramo
    • Niza
  • effective against pepsin and acid production
  • effective against nightime GERD 

6

H2 antagonists: Pharmokinectics:

  • Rapid intestinal absoprtion
  • First pass metabolism; Except Niazatidine
    • 50% bioavailability
  • Liver metabolism and urinary excretion are important for elimination
    • except nizatidine excretion=urinary
    • Renal trouble=reduce doses

7

Ranitidine

  • aka Zantac
  • H2 antagonist
  • removed from market due to NDMA carcinogen
  • Drug itself is fine

8

Cimetidine

  • H2 antagonist
  • Potent cytochrome P450 inhibitor
    • CYP1A2
    • CYP2D6
    • CYP3A4
  • May increase blood levels of 
    • warfarin
    • phenytoin
    • theophylline
    • calclium channel blockers
      • diltizem
      • felodipine
      • nifedipine

9

PPIs

  • Prazole family
    • ome
    • esome
    • panto
    • lanso
    • rabe
  • All are prodrugs
    • administered orally in enteric coated capsules
    • food reduces absorption-take before meal
    • Dissolution occurs in the intestine
    • compounds are lipophilic weak bases
      • diffuse into parietal cells and portonate=trapped to have efffect 
    • Takes a day for effects
    • Short half life, but irreversible inhibition leads to persistent effects

10

PPI Effectiveness

  • Daily dose is usually curative
    • peptic ulcer typically QD
      • once daily
    • GERD typically BID
      • twice a day
  • H. pylori can cause relapse 
    • most cases of peptic ulcer
    • usually given with antibiotic 
      • clarithromycin
      • metronidazole
      • amoxicillin

11

PPI Problems

  • Reduce absorption of:
    • vitamin b12
    • Mg2+
  • Changes in normal flora-increase in enteric infection
  • Increased Gastrin Signaling
    • elevated pH-->Positive feedback-->increase number of ECL cells
    • Concern about promoting cancer
  • Reduces Clopidogrel efficacy
    • inhibit CYP2C19
    • esomeprzaol and omeprazole reduce 50%
    • pantaprazole may also casue

12

PPIs: problem in elderly

  • Increased risk of:
    • c. difficile infection
    • bone fracture
      • due to reduced Mg2+ absorption
    • community-acquired pneumonia
    • mortality in finnish nursing homes
  • CORRELATION IS NOT CAUSATION

13

Agents for Mucosal Protection

14

Sucralfate

  • forms a paste
  • creates a physical barrier to acid and digestive enzymes
    • sticks to gastric lesions
  • Stimulates other protective responses
    • prostaglandin release
    • bicarbonate secretion
  • Safe and effect
    • little is absorbed
    • constipation may occur