antibiotics/antivirals 4

  1. Mechanism of Action
    All interfere with metabolism of organism
    • weaken cell wall
    • change cell wall permeability
    • alter protein synthesis
    • interfere with nucleic acid synthesis(can't reproduce)
    • Interfere with folic acid synthesis
  2. Bacteriostatic
    Alters or hinders growth or replication, control infection so immune system can eradicate it
  3. Bactericidal
    Destroys the bacteria
  4. Broad spectrum
    effective against many bacteria
  5. Specific or Narrow Spectrum
    effective against one or a few bacteria
  6. SuperBugs
    • MRSA- methcillin resistant Staph. Aureus
    • VRE- vancomycin resistant enteritis
  7. Adverse Reactions to Antibiotics
    • Hypersensitivities: from rash to anaphylaxis
    • Most common with penicillins & derivatives
    • Drug fever- hard to differentiate from infection--late onset
    • Delayed hypersensitivity reactions:
    • Steven-Johnson syndrome, erythema multiforma, toxic epidermal necrolysis
    • **Observe for 'bull's eye' lesions and STOP DRUG
    • Get a good allergy hx on all pts
  8. Resistance to antibiotics
    Caused partly by indiscriminate use of antibiotics
  9. Beta Lactam Antibiotics
    Penicillins (PCN)
    • Bactericidal
    • Resistance due to wide use
    • Narrow spectrum (gram pos, strep, staph)
    • Broad spectrum Penicillins include some gram neg (Ampicillin, Amoxicillin)

    • Adverse Effects:
    • allergy common
    • cross-sensitivity w/ other PCN's
    • rash most common, angioedema, anaphylaxis less common
    • diarrhea--c.diff
    • IV prep have high sodium- caution in pts w/CHF
    • cleared renally so lower dose for pts w/renal disease
  10. Cephalosporins
    cephalexin (keflex)
    • Same mechanism as penicillins--can be broad spectrum
    • ~10% cross-sensitivity to PCN's--especially w/ severe allergy

    • Adverse Reactions
    • resistance, diarrhea- c.diff, impaired renal function in high doses, bad reaction to ETOH- teach not to drink, 
    • Nursing
    • check allergies, if allergic to PCN monitor pt first few doses, if reaction to PCN is severe question order
    • Push PO fluids
    • monitor for diarrhea

  11. Sulfonamides-- 'Sulfa Drugs'
    • Bacteriostatic- interferes w/folic acid synthesis
    • broad spectrum

    • Uses:
    • UTI's, URI (upper respiratory infection), pneumonia, infectious diarrheas
    • Adverse Effects:
    • allergic reactions common, rashes&stevens-johnson syndrome (most common w/HIV infection), crystalluria--can lead to renal failure, risk w/dehydration--push fluids, rare anemia
  12. Trimethoprim
    • Broad spectrum
    • less resistance
    • (not a sulfa-- a folic acid antagonist)
    • synergistic w/sulfamethoxazole
    • similar adverse effects (ie: rashes, crystalluria)
    • Push fluids to prevent crystalluria!!
    • Report rashes!!
  13. Aminoglycosides
    Gentamycin (garamycin)
    • Narrow spectrum- primarily aerobic gram neg
    • bactericidal- dose dependent
    • inhibit protein synthesis
    • primarily parenteral (IV)
    • Adverse Reactions:
    • low incidence of allergy, nephrotoxicity, ototoxicity-(tinnitus, hearing loss, HA, vertigo, N/V, may be irreversible), neuromuscular blockade--can cause paralysis w/OD
    • high risk of hypocalcemia

    • Monistor peak & trough blood levels- calculate dose & interval based on weight, renal function, then adjust based on peak & trough
    • Nursing responsibility
    • keep meds on schedule
    • draw blood at peak & trough, if delayed report to lab&MD
    • Monitor:
    • BUN, creatinine, I&O, signs of hearing loss
    • push fluids
  14. Aminoglycosides
    • Narrow spectrum- gram pos, MRSA, c.diff
    • inhibits cell wall synthesis
    • reserved for severe infections
    • resistance-VRE

    PO or IV well diluted 

    • Adverse:
    • flushing reaction- red man syndrome (face, neck, chest, hypotension)
    • nephrotoxicity
    • hypersensitivity
    • ototoxicity
  15. Quinolone Antibiotics
    Ciprofloxacin (cipro)
    • Bactericidal- alter DNA synthesis
    • Broad spectrum--gram neg & gram pos
    • *Drug of choice for community acquired Pneumonia

    • Adverse
    • GI-nvd
    • CNS- dizziness, HA, confusion
    • Rare seziures
    • rashes
    • effects growing cartilage--not for children >18! or pregnancy
    • reduce dose for impaired renal functions

    • Nursing
    • well absorbed PO
    • No dairy products or grapefruit juice
    • Dilute well IV
  16. Macrolides--Erythromycins
    Azithromycin (zithromax)
    • inhibit protein synthesis
    • bacteriostatic low dose, bactericidal high dose

    • Uses
    • URI (upper resp. infec.)
    • pneumonia
    • chlamydia, gonorrhea
    • gram pos
    • substitute for PCN

    • Adverse
    • allergies uncommon
    • GI upset w/PO less w/IV
    • take w/food if needed
    • high dose IV-reversible hearing loss
    • thrombophlebitis--slow IV infusion
  17. Tetracyclines
    • Inhibit protein synthesis
    • Bacteriostatic, broad spectrum
    • Well absorbed PO
    • Uses: acne, chlamydia, rickettsia, Lyme dx, h.pylori
    • Adverse
    • Rare allergy
    • Photosensitivity common
    • GI upset common- take with food
    • Diarrhea--c.diff

    • Dont use in pregnancy or kids under 8
    • Dont take with dairy or antacids- will inactivate drug
    • Can aggregate renal failure, monitor
  18. Metronidazole (flagyl)
    Antibiotic against anaerobic bacteria, antiprotozoal, amebicide, bacteroids, c.diff, gardneralla, giardia, trichomonas, h.pylori

    • Adverse 
    • NVD
    • HA, metallic taste in mouth
    • Disulfiram reaction w/ETOH
    • Interacts w/Coumadin and lithium

    PO, IV, topical

    • Nursing
    • Teach not to take w/ETOH
    • Report adverse effects
  19. Anti tubercular drugs
    • Isoniazid
    • Rifamycin
    • Pyrazinamide
    • Ethambutol
  20. Isoniazid
    • Inhibit cell wall synthesis
    • Resistance uncommon
    • Uses
    • Treat active TB
    • Post exposure prophylaxis
    • Positive PPD, no active disease
    • Teach need for long term use
  21. Rifamycin (rifampin)
    • Uses-- TB
    • Prophylaxis formeningococcal and h.influenza meningitis
    • Adverse
    • GI irritation, colors body fluids orange, hepatotoxicity
    • Immune reaction w/intermittent use (flu like sx, vnd, myalgia to acute renal failure)
    • Teach
    • Plan for body fluid stain,contact lenses
    • Do Not Miss a dose
    • Monitor hepatic enzymes
  22. Pyrazinamide
    • Bacteriastatic or bactericidal
    • Used for TB
    • Adverse
    • Inhibits urate excretion- gout- check uric acid
    • Rare jaundice- monitor hepatic enzymes
  23. Ethambutol
    • Bacteriostatic-- used for TB
    • Adverse
    • Visual changes- may need to dc drug
    • GI upset
    • Confusion, HA
    • Teach to report visual changes- blurring, color blindness
    • Combination therapy results lower doses fewer adverse fewer resistance
    • Therapy lasts 3-6 months, 9 w/HIv
    • Major challenge=compliance
  24. Antiviral medications
    Oseltamivir (tamiflu)
    • Alternative to vaccination
    • Reduces severity and length of symptomatic period
    • Resistance from seasonal influenza, bit not from H1N1
    • Blocks replication of virus
  25. Adamantanes (amantadine)
    • Inhibit viral replication
    • Only effective in influenza A, many resistances
    • *must be taken when first flu symptoms identified (1st 2 days)
    • Adverse
    • Anxiety, insomnia, confusion
  26. Antiviralsdoor Herpes
    Acyclovir (Zovirax)
    • Inhibit DNA synthesis 
    • Widely distributed in body fluids, including breast milk and placenta
    • Adverse
    • Skin irritation w/topical application
    • NVD, HA, rash
    • High doses CNS symptoms- HA, confusion
    • Renal toxicity

    Chronic use for genital herpes for up to 10 years
  27. Treatment for hepatitis
    • Also used for RSV in children
    • Pregnancy category X
    • Aerosol for RSv can cause eye irritation
  28. Nucleoside/nucleotide reverse transcriptase inhibitors (NTRI's)
    Zidovudine (AZT)
    • Adverse
    • Fatigue, malaise, nausea, anorexia, HA, insomnia.  Typically resolves in firstfew weeks
    • Uses
    • Treatment of HIV
    • Prevent mother to child transmission
    • Post exposure prophylaxis
  29. Non-nucleotide reverse transcriptase inhibitors
    Saquinavir (invirase, fortovase)
    • Treats HIV, reduce death rate  of those seriously ill w/HIV
    • Adverse
    • NVD, abd pain, HA, altered taste, increased liver enzymes

    Long term effects- redistributed body fat
  30. HAART- highly activated antiretrovial therapy
    Protease inhibitor or non-nrti combined w/ 2 nrti drugs

    Combined agents affect virus at different stages of life span

    Goal- reduce viral load
  31. Amphotericin B
    Antifungal, primarily IV
  32. dverse 
    • Hypersensitivity, HA, NV, low BP
    • Confusion, joint/muscle pain
    • Nephrotoxicity
  33. Ketoconazole
    • Antifungal
    • Suppresses glucocorticoid production, can be used to treat cushings syndrome
    • PO, IV
    • Many drug interactions, hepatotoxicity
  34. Terbinafine (lamisil)
    • For the nails up to 3 months
    • Adverse- hepatotoxicity
  35. Nystatin (mycostatin)
    Anti fungal treats candidiasis
Card Set
antibiotics/antivirals 4
Pharmocology test 4 antibiotics/antivirals