Pharm T3

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Pharm T3
2012-10-24 14:48:49

Diez, 06,07,08
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  1. 3 mehanisms that may lead to Peptic Ulcer disease
    • Ethology- Infections (H. Pulori)
    • Hyperproduction of HCL- function of the parietal calls of the stomach
    • Inadequate mucosal defense against HCL
  2. Infectious
    • Antimicrobial agents (based on efficiency cure (erradication rate)
    • Current reginen of choice (90% erradication rate)
    • -2 week combo course with:
    • Bismuth 
    • Metronidazole
    • Tetracycline
    • Anti-secretory drug (usually added)
  3. Second line regiments (erradication rate 80-90%)
    • Combo of 2 antimicrobial agents:
    • Metronidazole
    • Amoxicillin or Clarithromycin
    • Antisecretory drug

    If you use 1 antimicrobial agent - have a 20-40% erradication rate
  4. What is the reccurrance rate of patients treated only with antisecretory agents?

    For those receiving recommended regimen- rate is less then 15%
  5. HCL production
    HCL secretion (parietal cells) is controlled by:
    • Actylcholine (increase intracellular Ca++ ion)
    • Histamine (activation of adenyl cyclase)
    • Prostaglandine E2 and I2 (lower HCL production)
    • Gastrin (increase intracellular Ca++ ion)
  6. The agents blocking the secondary messangers acting protein pump
    • Dicylomine blocks the cholinergic receptor
    • Cimetidine blocks the H2 histimine receptor
    • Misoprostol stimulates the prostaglandin receptor
    • Omeprazole blocks the proton pump
  7. H2 receptor antagonists Chief clinical use
    Inhibitor of gastric acid secretion by reducing intracellular concentration of cyclic AMP.
  8. H2 receptor antagonists Actions
    Fully reversible competitive antagonist of histamine receptors completely inhibiting gastric acid secretion, partial inhibition of gastric acid secretion induced by acetylcholine and bethanechol.
  9. H2 receptors antagonists Therapeutic use
    All agents are equally effective to promote gastric and duodenal ulcer healing. There may be a recurrance rate of 60-100% per year if H pylori superinfection is present

    • Zollinger-Ellison syndrome (gastrin producing tumor)
    • Acute stress ulcers
    • Gastroesophageal reflux
  10. H2 receptor antagonist agents
    • Climetidine (tagamet)
    • Ranitidine (zantac)
    • Famotidine (pepcid)
    • nizatine (axid)
  11. Cimetdine (tagamet)
    • Metabolized in the kidney- good to use if cant use a drug that is metabolized in the liver
    • 30% of dose is metabolized by microsomal enzymes thus 70% excreted unchanged in urine.
    • Due to its anti-androgenic and Prolactin stimulation, effect may induce gynecomastia, galactorreha, and decreased sperm count.
    • Is a P-450 enzyme inhibitor slowing metabolism of drugs that utlizes the system increasing their serum concentrations.
    • -Warfarin, Diazepam, Phenytoin,Quinidine, Carbamazepine, Teophylline, and Imipramine
  12. Ranitidine (Zantac)
    Longer acting and more potent than Cimetidine
  13. Famotidine (Pepcid)
    Similar to Ranitidine but more potent
  14. Nizatidine (Axid)
    Similar to Ranitidine but principally metabolized in the kidney and bioavailability is near 100%
  15. Prostaglandins
    Inhibits HCL secretion and stimulates mucus and bicarbonate production

    -Misoprostol (cytotec)
  16. Misoprostol (cytotec)
    • Clinically effective at higher doese and its routine use may be only justified in those patients- Using NAIDS
    • Since it produces uterine contraction it is contraindicated during pregnancy.
    • Diarrhea and nausea are the most common adverse effects
  17. Inhibitors of proton pump
    Supress secretion of H ion into gastric lumen
  18. Actions of inhibitors of proton pump
    Inhibits basal and stimulated gastric acid secretion. More then 90% of supression begins 1-2 hours after dose.
  19. Therapeutic use of proton pump inhibitors
    • Short term treatment of erosive esophagitis and duodenal ulcer.
    • Long term treatment of Zollinger- Ellison Syndrome.
  20. Agents of Proton pump inhibitors
    • Omeprazole (prilosec)
    • Lansoprazole (prevacid)
    • esomeprazole (nexium)
    • pantoprazole (protonix)
    • Rabeprazole (Aciphex)
  21. Adverse effects of proton pump inhibitors
    • Increased incidence of gastric Carcinoid tumor
    • prolonged hypochlorhydria
    • secondary hypergastrinemia
    • increased concentration of viable bacteria
    • Omeprazole interferes with oxidaton of Warfarine, Phenytoin, Diazepam, and Cyclosporine
  22. Antacids
    • Weak bases which react with gastric acid and water to form a salt diminsihing gastric acidity,
    • Many products varying in chemical composition, neutralizing capacity and sodium content.
  23. Agents of Antacids
    Aluminum or magnesium salts
  24. Adverse effects of Antacids
    • Constipation (aluminum) (maalox and mylanta)
    • diarrhea (magnesium) (gaviscon, mylanta)
  25. Mucosal protective agents
    • Sucralfate (carafate)
    • Colloidal bismuth
  26. Sucralfate (carafate)
    Complex of aluminum hydroxide and sulfated sucrose which forms a complex gel with mucus impairing diffusion of HCL.
  27. Colloidal bismuth
    • Inhibits pepsin
    • Increase mucus secretion
  28. Vomiting reflex center
    • Chemoreceptor trigger zone (caudal end of 4th ventricle) Responds to chemical stimuli in blood of CSF
    • Vomiting center (lateral reticular formation of medulla)- Coordinated the mechanical (motor) mechanism of vomit

    Although nausea and vomits are not exclusive of chemotherapy, 70-80% of patients will experience this symptom. 10-40% experience the symptoms before therapy due to anticipation.
  29. Emetic actions
    Agents or their metabolites may activate the center by the releasing and the actons of several neuroreceptors (Dopamine and Serotonine)

    Idiosyncratic response (smell, color, etc)
  30. Emetric Potential of chemotherapeutic drugs
    • Strong
    • Moderate
    • Mild
  31. Strong emetric potential
    (some used for leukemia)
    • Cisplastin
    • Mechlorethamine
    • Streptozocin
    • Decarbazine
    • Carmustine
    • Dactinomycin
  32. Moderate Emetric Potential
    • Cyclosphosphamide
    • Doxorubucin
    • Carboplastin
    • Mitomycin
    • Asparaginase
    • Azacytidine
  33. Mild Emetric Potential
    • Fluorouracil
    • Methortrexate
    • Etoposide
    • Vincristine
    • Bleomycin
  34. Drugs used to control chemotheraphy induced emesis
    • Phenotyazines
    • Substituted benzamines
    • Butyrophenones
    • Benzodiazepines
    • Corticosteroids
    • Canabinoids
  35. Phenotyazines (Prochlorperazine)
    Block dopamine receptors. Effective against low or moderate ematogenic agents (fluorourcil, doxorubicin)

    Side effects- Sedation, hypotension and extrapyramidal symptoms
  36. Substituted benzamines (Metoclopramide)
    Effictive at high dose against highly ematogenic agents (eg Cisplastin)

    Side effects- Sedation, diarrhea, and extrapyramidal symptoms limit high doses
  37. Butrophenones (haloperidol)
    Moderatly effective antiemetic
  38. Benzodiazepines (lorazepam, alprazolam)
    Requires a perscription- pt can get dependent

    • Low potency antiemetic agents
    • Beneficial properties include: Sedative anxiolitic and amnesic, useful in anticipatry vomits
  39. Corticosteroids (dexamethasone, methylprednisolone)
    Useful against mild to moderate emetogenic drug. May be involved in prostaglandin blockage.
  40. Canabinoids (mary jane) (dronabinol, nabilone)
    • Mariuana derivatives
    • Seldom used due to side effects: Dysporia, hallucination, sedation, vertigo, and disorientation.
  41. Serotonine Antagonists
    Ondansetron (Zorfan)
    Granisteon (Kytril)
    Block pripheral and central receptors. May be administered as a single does PO or IV and effective against all grades.

    • Ondansetron is also effective as post operative nausea and vomits
    • Headache is most common side effect
  42. Antiemetric Activity- High drugs
    • Serotonin antagonists
    • Substituted benzamide
    • Phenothiazine
  43. Antiemetric activity- Moderate
    • Butyrophenone
    • Corticosteriod
    • Cannabinoid
  44. Antimetic activity- Low
    • Antihistimine
    • Anticholinergic
    • Benzodiazepine
  45. Percent response fron drug combos
    • Dexamethasone, Ondansetron = 91%
    • Dexamethasone, Diphenhydramine, Metoclopramide, Droperidol = 76%
    • Lorazepam, Dexamethasone, Metoclopramide = 63%
    • Diphenhydramine, Dexamethasone, Metoclopramide = 58%
  46. Antidiarrheals
    • Diphenoxylate
    • Loperamide
    • Kaolin
    • Pectin
    • Methylcellulose
    • Activated attapuigite
    • Aspirin
    • Indomethacin
    • Bismuth subsaticylate
  47. Antidiarrheals
    Decreased motility (diphenoxylate, loperamide) (meperidine analogs) with Opiod like action= inhibits acetylcholine release, and decreases peristalsis
  48. Side effects of Antidiarrheals
    • Drowsiness, dizziness, and abdominal pain
    • May cause Toxic megacolon contraindicated in children and patients with colitis.
  49. Adsorbents (kaolin, pectin, methycellulose, and activated attapulgite
    • adsorption of toxins, or coating mucosa (protective)
    • -May interfere with absorption of other drugs

  50. Agents that modify fluid or electrolyte transport
    • NSAIDS (indometacine, asperine) by inhibiting prostaglandin synthesis.
    • Pepto Bismol (bismith subsalicilate (choice for traveler's diarrhea)
  51. Laxatives
    Castor oil, Senna, Aloe, Phenolphthalein, Bisacodyl, Hydrophilic colloids, Methylcellulose, Psyllium seeds, Bran, Magnesium hydroxide, Polyethylene glycol, Lactulose, Docusate sodium, Mineral oil, Glycerine suppositories
  52. Laxatives
    • Increase movement of food along GI
    • Irritants- Castor oil brake down to rinolinoleic acid which is very irritant and increases peristalsis.
    • Bulking agents (most effective)- Methylcellulose, psyllum seeds

    Stool softeners- Mineral oil and Glycerine suppositories
  53. Antimicrobial agents
    Drugs that are effective against microorganisms through "selective" toxicity without affecting the host cells.

    Appropriate agent
  54. FDA Catagory Antimicrobial fetal risk
    • A- No risk
    • B- only studies on animals, suggest potential toxicity 
    • C- Animal fetal toxicity demonstrated; human risk undefined
    • D- Human fetal risk present, but benefits outweigh risks
    • X- Fetal risk present, does not outweigh benefits; contraindicated in pregnancy.
  55. B category drugs
    • B- Lactams
    • B- Lactams with inhibitors
    • Cephalosporines
    • Aztreonam
    • Clindomyclin
    • Erythromycin
    • Azithromycin
    • Metronidazole
    • Nitrofurantoin
    • Sulfonamides
  56. C Catagory drugs
    • Chloramphenicol
    • Fluoroquinolones
    • Clarithromycin
    • Trimethoprim
    • Vancomycon
    • Gentamicin
    • Trimethoprim-sulfamethoxozole
  57. D Category drugs
    • Tetracyclines
    • Aminoglycosides (except gentamicin)
  58. Detecting the microbial agents
    • Direct microscopic visualation
    • Cultivation and Identification
    • Detection of microbial antigens
    • Detection of microbial RNA or DNA
    • Detection of host immune response
  59. Ideally
    Begin therapy after identification and sensitivity
  60. In reality
    Therapy is begun before ID and sensitivity determined
  61. Why would you begin therapy before the identification and sensitivity is determined
    May be detrimental to life
  62. Emperic therapy
    • Broad cover against bacterial infection
    • Effective against gram + and - anaerobes.
    • Combo of antibiotics or single broad spectrum

    You will get culure results and sensitivity depending on if it is gram + or -, or mixed flora
  63. Agent selection is by:
    • Patient history
    • Immune Status
    • Community vs Hospital acquired (nosocomial)
    • Site of infection
  64. Site of infection
    • Antibiotic has to reach the area
    • Difficult sites to reach sanctuaries
    • -Abcess
    • -BBB
    • -Prostate gland
  65. Host status
    • Immune status
    • Renal function (aminoglucosides)
    • Hepatic function (erythromycin)
    • Pregnancy (all agents cross the placenta)
    • Lactation
    • Age (all functions diminish with age)
  66. Bacterial factors
    Identity, Susceptibility
  67. Host Factors
    • Site of Infection
    • Allergies
    • Renal function
    • Hepatic function
    • Neutropenia- lack of adequate number of neutrophils
    • GI function
    • Underlying diseases
    • Concomitant drugs
    • Pregnancy
    • Desired route of administration
  68. Drug Factors
    • Activity against pathogen
    • Ability to arrive in site of infection
    • Potential drug interactions
    • Dosing frequency
    • Taste
    • Stability at different temperatures
  69. Cost of therapy
    • Often, several drugs have similar effectiveness but different costs.
    • ex Clarithromycin costs $120, and Tetracycline is $5
  70. Drug function- 2 ways
    • Bacteriostatic
    • Bactericidal
  71. Bacteriostatic
    • Drugs that arrest growth and replication of bacteria limiting spread of infection while immune system works.
    • These agents DONT kill the microorganism
    • ex- Chloramphenicol
  72. Bactericidal
    • Agents that eliminates (KILL) microorganism
    • ex- Penicillin
  73. ID sensitivity of organism
    • Take a culture in the media
    • MIC- Minimum inhibitory conc= lowest conc of an antibiotic that inhibits bacterial growth.
    • MBC- Minimum bactericidal concentration= The lowest conc of antiboitic that kills 99.9% of bacteria.

  74. Spectrum of therapy
    • Particular actibity of the drug
    • Narrow
    • Extended
    • Broad
  75. Narrow
    Single or limited group of organism (Isoniacid)
  76. Extended
    • Effective against gram + and gram - organism
    • Ampicillin
  77. Broad
    • Wide variety of microbial species
    • Teyracycline, Chloramphenicol
  78. Drug combination
    It is wise to use only one agent with higher specificity for the organism decreasing superinfection and emergence of resistant organism
  79. Drug combo advantages
    Synergism (combo is more efficient than either used separately (B- lactams and Aminoglycosides)
  80. Disadvantages to drug combos
    Some agents work only while organism is growing. If combined with bacteriostatic agent it becomes ineffective.
  81. Drug resistance
    • Bacterias are resistant when the agent fails to halt its growth by the maximal level of antibiotic tolerated by the host
    • Genetic alteration- Spontaneous mutation, Transfer of drug resisance by R factors (plasmids)
    • Modification of target site (eg Staph aureus)
    • Decrease accumulation (Decreased permeability for agent)
    • Enzymic inactivation (B- lactamase resistant organism)
  82. Complications of therapy
    • Hypersensitivity
    • Direct toxicity
    • Superinfections
  83. Hypersensitivity
    Reaction to drig or metabolites is frequent (eg Penicillin)
  84. Direct toxicity
    High levels in serum may be toxic to the host (Aminoglycoside produce ototoxicity)
  85. Superinfections
    Therapy may alter the normal flora allowing overgrowth of opportunistic organisms
  86. Prophylactic antibiotics
    • Situations in which antibiotics are used for prevention.
    • Restricted to situations where its use outweighs its potential risk.
  87. examples on when to use prophylactic antibiotics
    • 1- Prevention of strep infections in pts with a history of rheumatic heart disease. Pts may require years of treatment.
    • 2- Pretreatment of patients undegoing dental extractions who have implanted prosthetic devides, such as artificial heart valves, to prevent seeding of the prosthesis.
    • 3- Prevention of tuberculosis or menigitis among individuals who are in close contact with infection pts.
    • 4- Treatment prior to certain procedures to prevent infection.
    • 5 Treatment of the mother with zidovudine to protect the fetus in the cause of HIV infected, pregnant women.
  88. Classifications of antimicrobial agents
    • Inhibitors of metabolism (Sulfonamides, Trimethoprim)
    • Inhibitors of cell wall synthesis (B-Lactams, Vancomycin)
    • Inhibitors of protein sysnthesis ( Tetracyclines, Aminoglycosides, Macrolides, Clindamycin, Chloramphenicol)
    • Inhibitors of nucleic acid function or synthesis (Fluroroquinolones, Rifampin)
    • Inhibitors of cell membrane function (Isoniazid, Amphotericin B)
  89. Cell wall inhibitors
    • These agents are active against proliferating microorganisms
    • The most important members are the B-lactam antibiotics since the ring is esential for antimicrobial activity.
  90. Cell wall inhibitors
    • B lactam antibiotics:
    • Penicillins
    • Cephalosporines
    • Carbapenems
    • Monobactams

    • Other antibiotics:
    • Vancomycin
    • Bacitracin
  91. Penicillins
    Interfere with transpeptidation or cross-linkage, last stage of cell wall synthesis.

    • Rationale: Makes bacterial wall less stable and osmotically fragile, therefore bactericidal in nature
    • Ineffective against organisms that don't synthesize peptidoglycans as: mycobacteria, protozoa, fungi, viruses.

    • Penicillins bound to preiplasmic "receptors" where bacterial enzymes work to produce and modify its wall.
    • Many bacteria produce autolysins for remodeling the wall.
    • In presence of Penicillins they "synergistically" destroy its wall.

    Obtained from the mold. Penicillum chrysogenum

    • Differ from the substrate R group:
    • Natural Penicillins: Antistaphylococcal
    • Semi-synthetic: Extended spectrum, Antipseudomonal.
  92. Standard Penicillins
    • Crystalline penicillin G (IV)
    • Penicillin V (po)
    • Aqueus procaine penicillin G (IM)
    • Benzathine penicillin G (IM)
  93. Antistaphylococcal Penicillins (COMND)
    • Methicillin (IV)
    • Nafcillin (IV)
    • Isoxazloyl penicillins (IV)
    • Oxacillin (IV)
    • Cloxacillin (PO)
    • Dicloxacillin (PO)
  94. Aminopenicillins
    • Ampicillin (IV or PO)
    • Amoxicillin (IV or PO)
  95. Antipseudomonal penicillins
    • Carboxygenicillins
    • Carbenicillin (IV)
    • Ticarcillin (IV)

    • Ureidopenicillins
    • Piperacillin (IV)
    • Azlocillin (IV)
    • Mexlocillin (IV)
  96. Natural Penicillins
    Pen G. (benzylpenicillin)

    • used IV or IM- effective against Gram + and - organisms but is susceptible to inactibation by B-lactamase penicillinases.
    • Not resistant to acid (not used orally)
  97. Therapeutic applications for Penicillin G
    • Streptococcus sp. (pneumoniae, pyogens, viridans)
    • Neisseria sp (gonorrhea, meningitides)
    • Clostridium perfringes
    • Bacilus antracis
    • Corynebacterium diphteriae
    • Treponema pallidum
  98. Pen V.
    Similar spectrum to Pen G. but more acid stable (used in oral indections by anaerobes)
  99. Antistaphylococcal
    Penicillinase resistant agents use restricted for resistant organisms (COMND)
  100. Semi-Synthetic penicillins
    • extended spectrum
    • ampicillin
    • amoxicillin
    • Spectrum similar to Pen G.- but more effective against Gram  (-)
  101. Resistance
    Can be natural or acquired
  102. Natural Resistance
    Organism lacking peptidoglycan cell wall
  103. Acquired Resistance
    • Plasmid transfer (significant problem)
    • B-lactamase activity (constitutive vs. acquired)
    • decreased permeability to drug
    • altered penicilin binding proteins
  104. Pharmacokinetics
    • Route determned by stability to gastric acid and severity of infection
    • PO- oral
    • Depot (IM) Procaine, Pen G, and Benzyl Pen G)
    • IV (antipseudomonal)
  105. Absorption
    Most are incompletly absorbed after oral intake (except amoxicillin)
  106. Distribution of Penicillin
    Free drug is distributed well including the placenta but the hemato-encephalic barrier is limited to acute stages of disease
  107. Matabolism of Penicillin
    Usually insignificant
  108. Excretion of Penicillin
    Primary route is renal tubular secretion and glomerular filtration
  109. Adverse reactions of Penicillin
    • Hypersensitivity (most important) 5% of patients (penicilloic acis reacts with proteins (hapten))
    • Diarrhea
    • Nephritis (eg. Methicillin)
    • Neurotoxicity (may produce seizures if injected intrathecally)
    • Platelet dysfunction (antipseudomonal)
    • Caution toxicity- usually administered as Na+ or K+ salts (avoided by ising the most potent which allow for lower doses)