VetMed Antibiotics

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VetMed Antibiotics
2014-03-03 21:51:06

For vet med
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  1. Beta-lactams
    • Mechanism: Inhibitors of cell wall synthesis
    • Activity: Bactericidal
    • Dose: Time-dependent
    • Resistance: Beta-lactamases 
    • Distribution: Wide, extracellular fluids. Poor deep tissue w/o inflamation. Poor bioavailability.
    • Elimination: Renal, unchanged
    • Adverse effects: Type A: GI toxicity, cardio, CNS. Type B: Immediate, delayed. Cross reactivity between beta lactams possible 
    • Other: Post-antibiotic effect
  2. Basic penicillins
    • Stereotypic: Penicillin G, Penicillin V
    • Effective: Extracellular bacteria, Gram+ and pastuerella
    • Notes: Eagle effect
  3. Aminopenicillins
    • Stereotypic: amoxicillin, ampicillin
    • Effective: Extracellular bacteria, Gram+ and pasteurella, some gram -
    • Notes: Eagle effect
  4. Beta-lactamase resistant penicillins
    • Stereotypic: methicillin, oxacillin
    • Effective: Extracellular bacteria, Gram + with beta-lactamases.
    • Notes: Eagle effect
  5. Extended spectrum penicillins
    • Stereotypic: ticarcillin, piperacillin
    • Effective: Extraceullar bacteria, gram - including pseudomonas and proteus
    • Notes: Eagle effect, NEVER to be used empirically.
  6. Cephalosporins
    • Mechanism: Inhibitors of cell wall synthesis
    • Activity: Bactericidal
    • Dose: Time-dependent
    • Resistance: Beta-lactamases (but less so)
    • Distribution: Wide extracellular, poor penetration into deep tissues. Better bioavailability, better in pus.
    • Elimination: Renal, unchanged
    • Adverse Effects: Type A: GI toxicity (more so), nephrotoxic. Type B: Allergic, potential cross reactivity
    • Notes: Post antibiotic effect. Label use only in food animal. Significant differences between groups. Synergistic with aminoglycosides.
  7. First Generation Cephalosporins
    • Stereotypic: Cefazolin, cephalexin, cephaloridine.
    • Activity: Gram+ anaerobic and beta lactamase+
  8. Second Generation Cephalosporins
    • Stereotypic: Cefuroxine, cefotetan
    • Activity: Decreased Gram+ and increased Gram- vs ceph gen 1.
  9. Third Generation Cephalosporins
    • Stereotypic: Ceftiofur, ceftazidime, cefovecin, ceftriaxone.
    • Activity: Decreased gram + and increased gram - vs ceph gen 2 (even more so than gen 1)
  10. Cefovecin
    • Third generation cephalosporin.
    • Very long half life (14 days); allowing one injection.
  11. Beta-lactamase inhibitors
    • Stereotypic: Clavulanic acid, sulbactam.
    • Activity: Against certain beta lactamases.
    • Distirbution: Clavulanic acid available orally, sulbactam is not.
    • Elimination: Renal
  12. Carbapenems
    • Stereotypic: Imipenem
    • Activity: Bactericidal, wide spectrum. 
    • Dose: Time dependent.
    • Resistance: Exists, especially in pseudomonas 
    • Notes: Post antibiotic effect. Not to be used empirically, never first line.
  13. Monobactams
    • Stereotypic: Aztreonam
    • Activity: Bactericidal, most Gram - 
    • Dose: Time dependent.
    • Resistance: Exists. 
    • Notes: Post antibiotic effect. Not to be used empirically, never first line.
  14. Glycopeptides
    • Mechanism: Inhibitors of cell wall.
    • Stereotypic: Vancomycin
    • Activity: Bactericidal, only Gram+ 
    • Dose: Time and concentration dependent.
    • Resistance: VR genes emerging.
    • Distribution: Poor oral absorption, IV only.
    • Elimination: Renal, severely nephrotoxic. 
    • Notes: Banned in food animal. Never used empirically, never first choice.
  15. Polymyxins
    • Mechanism: Disruptor of cell membranes and "anti-endotoxic."
    • Stereotypic: Polymyxin B. 
    • Activity: Bactericidal, Gram - only, including pseudomonas.
    • Dose: Concentration dependent.
    • Resistance: Meh.
    • Distribution: Poor oral absorption, IV and topical only.
    • Elimination: Renal, nephrotoxicity and neurotoxicity possible.
  16. Bacitracin
    • Mechanisms: Cell wall synthesis inhibitors.
    • Activity: Bactericidal, gram + 
    • Dose: Time dependent, not orally absorbed. Usually given topically. 
    • Note: Highly nephrotoxic when used systemically.
  17. Aminoglycosides
    • Mechanism: Inhibitor of 30S ribosome in presence of O2.
    • Stereotypic: Streptomycin, spectinomycin, neomycin, gentamicin, amikacin.
    • Activity: Bactericidal, mainly gram- (some work on gram+) in presence of O2.
    • Dose: Concentration dependent.
    • Resistance: Rapid development, food animal residues in kidneys. 
    • Distribution: Mainly extracellular, inactivated in acid or pus, poor oral bioavailability, poor in deep tissue (CNS, eye, etc.), decreased activity in presence of Ca++ or Mg++.
    • Elimination: Renal, unmetabolized. 
    • Adverse Effects: Nephrotoxicity, ototoxicity (deafness or ataxia). Hypersensitivities are rare. 
    • Note: Post antibiotic effect. Synergistic with cell wall synthesis inhibitors, cannot be combined in same syringe with penicillins. Avoid in food animals, no off label use.
  18. Tetracyclines
    • Mechanism: Inhibitor of 30S ribosome
    • Stereotpyic: Tetracycline, oxytetracycline, cholotetracycline, doxycycline.
    • Activity: Bacteriostatic. Broad spectrume (Gram +/- a/anarobes). Extra and intracellular and some protozoans. 
    • Dose: Time dependent. 
    • Distribution: Absorbed orally. Decreased absorption with food, decreased with divalent cations (milk). Penetrates into deep tissue (CNS even w/o inflammation) 
    • Elimination: Renal and hepatic. Exception is doxycycline is 100% liver. 
    • Adverse Effects: Relatively safe, GI upset (increased risk in hindgut fermentors). Binds to bone and teeth. Hypersensitivity is uncommon.
  19. Macrolides
    • Mechanism: Inhibitor of 50S ribosome. 
    • Stereotypic: Erythromycin, spiramycin, tulathromycin, tylosin, tilmicosin
    • Activity: Bacteriostatic, aerobic Gram+, extra and intracellular. 
    • Dose: Time dependent. 
    • Distribution: Inactivated by acid, variable oral absorption. Penetration into most deep tissue except CNS (w/o inflammation) 
    • Elimination: Liver metabolism and elimination. 
    • Adverse Effects: Inhibits CYP450, GI irritants, flora alterations, prokinetic effect (contraindicated in hind gut fermentors). Tilmicosin is cardiotoxic.
    • Resistance: Widely present, resistance confers resistance to 3 classes.
    • Notes: Anti-inflammatory, GI prokinetic
  20. Lincosamides
    • Mechanism: Inhibitor of 50S ribosome.
    • Stereotypic: Lincomysin, clindamycin, pirlimycin.
    • Activity: Bacteriostatic, mainly gram+ obligate anaerobes, extra and intracelluar. 
    • Dose: Time dependent 
    • Distribution: Good oral absorption. Good penetration into deep tissue except CNS (w/o inflammation). 
    • Elimination: Liver metabolism and elimination. 
    • Adverse Effects: GI upset, severe diarrhea in herbivores. Peripheral neuromuscular blockage. Cardiac depression.
  21. "Phenicols"
    • Mechanism: Inhibitor of 50S ribosome.
    • Stereotypic: Chloramphenicol, florfenicol
    • Activity: Bacteriostatic, broad spectrum, extra and intracellular.
    • Dose: Time dependent. 
    • Distribution: Good oral absorption. Enter most deep tissue including CNS.
    • Elimination: Liver metabolism (glucuronidation) and liver elimination. Inhibitor of CYP450.
    • Adverse Effects: Inhibitor of CYP450. Bone marrow toxicity, cats more sensitive. Aplastic anemia not reported in vet med. GI toxicity, horses very susceptible. 
    • Notes: Chloramphincol is banned in food animal. Florfenicol okay for labeled use.
  22. Fluoroquinolones
    • Mechanism: Prevent DNA replication
    • Stereotypic: Enrofloxacin, ciprofloxacin, marbofloxacin, orbafloxacin
    • Activity: Bactericidal. Aerobic gram-, extra and intracellular. Variable gram+.
    • Dose: Dose dependent.
    • Distribution: Well absorbed orally. Good penetration in deep tissues (except CNS)
    • Elimination: Renal. (Exception: enrofloxacin is metabolized to cipro)
    • Adverse effects: Immunomodulatory. Relatively safe. Mild GI. Articular damages in growing juveniles, tendon ligament toxicity. Phototoxicity. Rentinal degradation in felines. Neurotoxicity, decreases seizure threshold. Relatively common drug hypersensitivity, cross reactivity possible. 
    • Notes: Lowered efficacy when concentrations too high. Banned in food animal off label. Avoid as first line. 
  23. Rifamycins
    • Mechanism: Inhibit RNA polymerase
    • Stereotypic: Rifampin
    • Activity: Bactericidal. Aerobic gram+.
    • Dose: Concentration dependent. Extra and intracellular.
    • Distribution: Good penetration into deep tissue, including CNS w/o inflammation. 
    • Elimination: Liver metabolism (P450 and acetylation) and liver excretion.
    • Adverse Effects: Liver enzyme inducer, drug interactions. Hepatotoxic (in dogs). Bone marrow toxicity. Teratogenicity. Hypersensitivity uncommon.
    • Notes: Banned in food animal.
  24. Nitroimidazoles
    • Mechanism: Direct DNA damage
    • Stereotypic: Metronidazole
    • Activity: Bactericidal on in anaerobic conditions. Gram-, some gram+ and some protozoans. Extra and intracellular. 
    • Dose: Time or concentration dependent depending on organism.
    • Distribution: Well absorbed orally. Very good deep tissue penetration including CNS.
    • Elimination: Liver metabolism (P450 and glucuronidation) and mixed hepatic and renal elimination.
    • Adverse Effects: GI toxicity, floral alteration. Unpalatable. Neurotoxicity at high doses. Drug interactions with liver metabolism. Carcinogenic and teratogenic. 
    • Notes: Ester benzoate compounds available to increase palatability, but toxic to cats in high doses. Banned in food animal.
  25. Sulfonamides
    • Mechanism: Compete with PABA for the synthesis of folic acid in bacteria.
    • Stereotypic: Sulfamethoxazole, sulfadiazine, sulfadimentoxine.
    • Activity: Bacteriostatic. Decreased in pus. Gram + and gram - aerobes, some protozoans. Extracellular. 
    • Dose: Time dependent.
    • Distribution: Good oral absorbtion. Good penetration into CNS and prostatic secretions. 
    • Elimination: Liver metabolism, mixed liver and renal elimination. 
    • Adverse Effects: Reversible inhibition of thyroid hormone. Keratoconjunctivitis sicca (KCS) in dogs. Nephrotoxicity. Immune mediated blood cytopenia as a type B reactions. Drug hypersensitivity. 
    • Notes: Banned in lactating dairy cattle.
  26. Diaminopyrimidines
    • Mechanism: Prevent the activation of folic acid to folinic acid.
    • Stereotypic: Trimethoprim, ormetoprim
    • Activity: Bacteriostatic. Gram + and gram - aerobes, some protozoans. Extra and intracellular bacteria. 
    • Dose: Time-dependent.
    • Distribution: Well absorbed orally. Good penetration into deep tissue (CNS, prostate) and fluids (bile, urine, milk).
    • Elimination: Liver metabolism, liver excretion.
    • Adverse Effects: Folate toxicity, causing Type A blood cytopenia, neural tube defects. Drug hypersenitivity.  
  27. Potentiated Sulfanomides
    • Mechanism: Combination of sulfanomides and diaminopyrimides.
    • Stereotypic: Sulfamethoxzole + trimethoprim, sulfadimethoxine + ormetoprim, sulfdiazine + trimethoprim.
    • Activity: Bacteriostatic, potentially bacteriocidal. Extra and intracellular. 
    • Dose: Time dependent.
    • Distribution: Extension of sulfanomides into deep tissue. 
  28. Nitrofurans
    • Mechanism: Deprive bacteria of Acetyl CoA for energy production, direct damage to DNA.
    • Stereotypic: Nitrofurantoin
    • Activity: Bacteriostatic or bactericidal. Gram + and gram -, aerobic and anaerobic. Mainly extracellular. Some protozoans. 
    • Dose: Can be used locally or low-dose oral for UTI.
    • Distribution: Absorbed orally. Poor tissue distribution. 
    • Elimination: Liver metabolism and bioactiviton, quick renal excretion and concentration. 
    • Adverse Effects: Very toxic. Drug allergies common.
    • Notes: Not to be used as first line. Banned in food animals (even topical).