Antibiotics Antivirals 2006

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Antibiotics Antivirals 2006

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

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