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  • 1. Antibiotics, Antivirals Barbara S. Hays, RN Winter 2006
  • 2. Principles of antimicrobial therapy
    • Bactericidal agents: kill organisms
    • Bacteriostatic agents: inhibit growth, usually by inhibiting protein synthesis
  • 3. Antimicrobial therapy mechanisms of action
    • Inhibition of cell wall synthesis
      • Penicillins, Cephalosporins
        • Organism becomes osmotically unstable: lysis
    • Inhibition of protein synthesis
      • Aminoglycosides
        • Cause formation of abnormal proteins/inhibit synthesis by irreversible binding to ribosomal subunit
    • Disruption/alteration of membrane permeability
      • Antifungals
        • Bind to specific cell wall components
        • Organism leaks cellular components
  • 4. Antimicrobial therapy mechanisms of action, II
    • Inhibition of nucleic acid synthesis (RNA/DNA)
      • Antivirals
    • Inhibition of specific biochemical pathways
      • Bacteriostatic agents
      • Competitively inhibit metabolic pathways that are critical to survival of the organism
  • 5. Selection of antibiotics
    • Sometimes broad spectrum antibiotics before Culture/Sensitivity (“C&S) results
    • Once results in: change to least toxic antibiotic to which organism is sensitive
    • Gram stain
      • Positive (holds purple stain)
        • Also see if cocci, rods, etc
      • Negative (takes red counterstain)
  • 6. Selection of antibiotics
    • Combination therapy
      • When synergistic effect desired
      • When development of resistance is a problem, like with TB
      • When nature of infection is not known [or multiple, mixed organisms]
  • 7. Administration of antibiotics
    • Oral
      • Unpleasant taste
      • GI upset
      • Client may stop taking when begins to feel better – relapse and resistance a concern
    • Intramuscular
      • Painful/irritating (may mix with lidocaine)
      • Rotate injection sites
      • Avoid in shock/hypoperfusion states
      • [vancomycin IM causes tissue necrosis]
  • 8. Administration of antibiotics
    • Intravenous (requires the most nsg care)
      • When high concentrations must reach site
      • When client unable to take oral meds, or if oral absorption is poor
      • When antibiotic of choice is only available in this form
    • Nursing implications
      • Accurate/timely administration is a must
        • Inadequate response
        • Development of resistant organisms
      • Drug imcompatibilities
      • Phlebitis
  • 9. General side/adverse effects of antimibrobials
    • Allergic reactions
      • Generalized rash to life-threatening anaphylactic shock
        • Rashes: mild – antihistamines (or tolerate it)
        • Anaphylactic reactions
          • Hypotension
          • Cardiovascular collapse
          • Bronchoconstriction
          • Laryngospasm
  • 10. General side/adverse effects of antimibrobials
    • Superinfections/opportunistic infections
      • Normal flora altered
        • Buttermilk, live cultured yogurt
      • Some resistant to current antibiotic flourish
    • Other
      • Fluid/electrolyte (many are sodium salts)
        • Fluid retention, CHF
      • GI upsets (n/v/d)
  • 11. Antibiotic use during pregnancy
    • All antimicrobials cross placenta to some degree. May be teratogenic (not much literature, so physicians are careful)
    • Tetracyclines
      • Disrupt tooth/bone formation in fetus
  • 12. Antibiotic use in children and the elderly
    • Children
      • Absorption, distribution, metabolism and excretion issues
      • Elimination dependent on health of kidneys
      • Immature liver of neonate may be unable to inactivate the medication
    • Elderly
      • Similar to very young because of diminished functions
  • 13.  
  • 14. Aminoglycosides (“Easy” p 473)
    • Gentamycin/Garamycin prototype (p 474)
      • Bactericidal against gram negative, gram positive, myocbacteria [TB, Leprosy], and protozoans
      • Poorly absorbed [“gut active”, esp. neomycin] so given IV or IM
      • Penicillin assists to transport across cell membrane
      • Toxic (so peak/trough levels)
        • Kidneys (if doesn’t drop below 2mcg/ml) – keep well hydrated and watch BUN/creatinine levels
        • Nerves
        • 8 th cranial nerve: hearing (if rises above 12 mcg/ml)
        • Allergic reactions, anaphylaxsis
        • agranulocytosis
  • 15. Penicillins (“Easy” p 477)
    • Natural penicillins (Prototype p 479). Mold.
      • About all there was during WWII
        • Then most staph was susceptible to PCN.
        • Now over 90% of the strains are resistant to PCN.
    • Penicillinase
    • Penicillinase-resistant penicillins
      • Methcillin, Staphcillin, Unapen
      • [MRSA – can live on your hands for three hours]
    • Aminopenicillins
      • Ampicillin, Unasyn (may cause nephritis, agranulocytosis)
    • Extended spectrum penicillins
      • Ticarcillin, Pipercillin
  • 16. Penicillins (“Easy” p 479, 480)
    • Drug interactions
      • Probenecid increases plasma concentration by competing for excretion by kidneys
      • Decreased effectiveness of hormonal contraceptives
      • Large doses can cause bleeding
      • High doses inactivate aminoglycosides (while lower doses help…)
  • 17. Penicillins (“Easy” p 480)
    • Adverse reactions
      • Hypersensitivity
        • Rash to anaphylactic shock
      • GI upset
        • Tongue inflammation (stomatitis, glossitis)
        • n/v/d
      • Liver toxicity by Oxacillin
  • 18. Cephalosporins (“Easy” p 482)
    • Derived from fungus, structurally similar to PCNs
    • Divided into “generations” based on spectrums of activity, typically broader with each generation
      • First generation
      • Second generation
      • Third generation
      • Fourth generation
  • 19. Cephalosporins
    • Things to consider (p 486)
      • Antabuse-like reaction up to 72 hours after dose
      • Increased risk of bleeding with some
      • Risk of cross-allergy to those sensitive to PCNs
  • 20. Tetracyclines (“Easy” p 489)
    • Prototype: p 490
      • Tetracycline HCl (Achromycin)
      • Vibramycin
      • Aureomycin
    • Work well for acne, respiratory infections, syphilis (but bacteria may become resistant)
    • Absorption reduced with milk, antacids, calcium
  • 21. Tetracyclines
    • Adverse reactions (p 491)
      • Superinfection
      • GI upset
        • Stomatitis, “black hairy tongue”
        • n/v/d
      • Photosensitivity
      • Hepatic toxicity
      • Renal toxicity
      • Affects forming teeth/bones
  • 22. Macrolides (“Easy” p 495)
    • Erythromycin
      • Acid sensitive (so need enteric coating)
      • Cross BBB only with inflammation
      • Effective for those with PCN allergy
      • Use for Chlamydia [Ilotycin for neonates]
    • Adverse effects (see p 497)
  • 23. Vancomycin (“Easy” p 498)
    • Used for treating MRSA
      • Adverse reactions (p 499)
        • Hypersensitivity/anaphylaxsis
        • “ red man syndrome”
        • Neutropenia
        • Hearing loss (temporary/permanent)
    • VRE’s… [can live on surfaces for weeks!]
  • 24. Fluoroquinolones [“quinolones”] (“Easy” p 507)
    • Used frequently in urinary tract infections
    • Synthetic, broad spectrum
    • Slow microbial resistance
    • Food/dairy products reduce absorption
    • Family members
      • Cipro (ciprofloxacin)
      • Levaquin (levofloxacin)
      • [NegGram (naladixic acid)]
      • Floxin (ofloxacin)
  • 25. Fluoroquinolones [“quinolones”]
    • Interact with many medications
    • GI upset
    • Compete with probenecid for excretion in the kidneys
    • (go over client teaching p 509)
  • 26. Sulfonamides (“Easy” p 510)
    • Prototype pro p 511 [Septra/Bactrim]
    • Used for UTIs, ear infection, newborn eye prophylaxsis
    • Give on empty stomach with full glass of water
      • Cause crystalluria and subsequent stone formation (client to drink 2-3 quarts/day)
  • 27. Sulfonamides
    • Adverse reactions (p 511)
      • Urine crystals
      • Hypersensitivity/allergy
      • Increased effects of oral hypoglycemic agents
  • 28. Antitubercular (“Easy” p 540 – 545)
    • Tuberculosis: on the rise again…
      • Droplet spread
      • Already tough to treat, is becoming more and more resistant
    • Currently recommending 4-fold attack (p 540). Bring out the big guns. In combination.
      • Isoniazid (INH)
      • Rifampin [also used for severe, resistant infections]
      • Pyrazinamide
      • Streptomycin or ethambutol
    • Client non-compliance
      • Long term therapy, expense (6-9-12 months)
      • “ DOT” therapy (directly observe client taking the med)
  • 29. Antitubercular meds
    • Side effects/adverse effects to consider
      • INH
        • Peripheral neuropathy
        • hepatotoxicity
      • INH and Ethambutol
        • Visual disturbances
      • Streptomycin
        • Ears
        • kidneys
  • 30. Antifungal drugs (“Easy” p 545)
    • Go over p 546 and put in names
      • Clotrimazole (GYNe-Lotrimin, Mycelex)
      • Grisofulvin (Fulvicin)
      • Miconazole (Monistat)
  • 31. Polyenes (“Easy” p 545)
      • Amphoteracin B [“ampho-terrible B” and Diflucan p 554]
      • Nystatin (Mycostatin) -- topical
      • (esp. Amphoteracin B) – drug interactions (p 547)
        • Serious interactions with many drugs
        • Kidney toxicity
        • Produces hypokalemia (as do steroids and extended release PCNs. Watch for digitalis toxicity!)
  • 32. Diflucan (p 554)
    • Much like amphoteracin B
    • Drug interactions (p 555)
  • 33.  
  • 34. Antivirals (“Easy” p 516 – 539)
    • Acyclo vir /Zo vir ax (prototype pro p 517)
      • Disrupts viral replication
    • Used to treat
      • genital herpes, simplex II
      • Shingles (chickenpox virus)
      • C yto M egal V irus (CMV) in those immunocompromized with AIDS
    • Adverse reactions (p 518)
  • 35. Antivirals
    • [Relenza (zanam vir )]
      • Funky powder to inhale
      • Does not permit release of newly formed viruses from surface of infected cells
      • Works for flu A and B
  • 36. Antivirals
    • Riba vir in (“Easy” p 522 – 526
      • Inhaled gives high concentrations in lungs
      • Good for children with RSV
      • (of course you remember about children, viral illnesses, ASA, and Reye’s Syndrome…)
  • 37. Antivirals to treat advanced HIV
    • Retro vir (AZT) to treat AIDS
      • IV to prevent transmission to fetus
    • Combination therapy works best
    • Go over adverse reactions p 531
    • Teaching (go over p 531)