AMINOGLYCOSIDES

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AMINOGLYCOSIDES

• -Used with serious gram negative bacterial
  infections
• -suffix micin or mycin (exception Amikacin)
• NOTE tetracyclines also use mycin
• Amikacin
• Injection
• Gentamicin
• Topical, injectable
• Neomycin
• Topical, oral

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AMINOGLYCOSIDES

• -Bactericidal by affecting the ability of
  bacterias ribosomes to assemble proteins
• -Aminoglycosides must be inside the bacterial
  cell to produce its effects and oxygen must be
  present for Aminoglycosides to enter
• Ineffective against anaerobic bacteria and in
  areas lacking oxygen (colon, deep puncture
  wounds)
• The concurrent use penicillin enhances the
  ability of Aminoglycosides to enter
• -Once daily dosing is safest

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AMINOGLYCOSIDES

• -Absorbed well through skin that is not intact
• -Pyogenic infections limit the action of
  Aminoglycosides as the medication will bind to
  the debris instead of the bodys cells. Clean
  wound first.
• NEPHROTOXOCITY and OTOTOXICITY are side effects
  of normal, high, or frequent doses as
  Aminoglycosides accumulate in the kidneys and
  inner ear (this can also be true for fetuses as
  they easily cross the placenta)
• Nephrotoxicity may be reversible if the drug is
  reduced /withdrawn before there is necrosis in
  the tubules
• Accumulation in the inner ear can cause deafness
• Ototoxicity can also affect balance

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FLUOROQUINOLONES (QUINOLONES)

• -Most have floxacin as a suffix
• Ciprofloxacin (Cipro)
• Oral and injectable
• Used in small and large animals
• Enrofloxacin (Baytril)
• Oral, Injectable, and topical
• Used in small and large animals
• Marbofloxacin (Zeniquin)
• Oral
• Used in small animals
• Orbifloxacin (Orbax)
• Oral
• Used in small animals

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QUINOLONE MECHANISM OF ACTION

• -Interfere with bacterial DNA which must be
  tightly coiled. Quinolone attack the bacteria's
  enzyme gyrase whose role is to supercoil
• -Bactericidal
• -Effective against common gram negative and
  positive bacteria (except Strep)
• -Used for skin, urinary, prostatic, and
  respiratory infections
• -Absorbed better when administered orally in
  small animals and by injection in large animals

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FLUOROQUINOLONES

• -Can cause bubblelike lesions in rapidly growing
  cartilage. Degenerate and arthritic changes can
  arise as adults
• contraindicated In growing animals
• -High doses in cats can cause changes in the
  retina, leading to blindness
• -Reserve for serious infections as bacterial
  resistance is a problem
• -Fluoroquinolones cannot be used extra-label on
  food animals

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TETRACYCLINES

• -Used in large and small animals
• -Used to TX RMSF, ehrlichiosis, salmon
  poisoning, hemobartonellosis, mycoplasma
  pneumonia, Chlamydia, psittacosis, Lyme disease
• -cycline suffix
• -Older tetracyclines tetracycline and
  oxytetracycline, newer tetracyclines
  doxycycline, minocycline

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TETRACYCLINES

• -Bacteriostatic
• -Bind to bacterial ribosomes and prevent RNA from
  attaching. This stops protein synthesis.
• Inhibit cellular function and division.
• Rely on the body having a functional immune
  system since they are Bacteriostatic

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TETRACYCLINE PRECAUTIONS

• Chelators of calcium which can effect developing
  teeth and bones
• If given to young, growing animals both can be
  effected
• Dentin and enamel formation can be disrupted and
  a yellow discoloration may develop
• Bone development can be slowed if calcium is
  chelated
• GI upset may be seen with oral administration
• Normal flora in rumen can be killed off causing
  rumen inactivity
• Irritation of GI mucosa in dogs causing V/D,
  anorexia
• Cats are susceptible to esophageal stricture-
  chase with at least 6 mL water

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TETRACYCLINE PRECAUTIONS

• DO NOT GIVE IV TO HORSES
• Arrythmias, collapse, and death
• Give slowly IV to other species
• Expired tetracycline and oxytetracycline can form
  a nephrotoxic compound that damages the PCT.
• Causes FANCONIS SYNDROME- glucose reabsorption
  is impaired.
• Glucosuria without hyperglycemia

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SULFONAMIDES POTENTIATED SULFAS

• AKA Sulfa drugs
• Resistance is seen because of overuse
• Often potentiated to increase efficacy and make
  them bactericidal (otherwise Bacteriostatic)
• Trimethoprim and ormetoprim
• Commonly used sulfa drugs
• Sulfadimethoxine (Albon, combined with ormetoprim
  in Primor)
• Sulfadiazine (combined with trimethoprim in
  Tribrissen)
• Sulfasalazine (GI)

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SULFONAMIDES

• BACTERIOSTATIC organisms that make their own
  folic acid needed for protein and nucleic acid
  metabolism. Sulfonamides block an enzyme needed
  for this process. Potentiators block different
  enzymes, but still those that are required for
  folic acid. When combined, the compound is
  BACTERICIDAL.
• Broad spectrum many G and G- bacteria,
  coccidian, and Toxopasma
• Often used for UTIs.

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SULFONAMIDES

• Sulfonamides are known to produce
  keratoconjunctivitis sicca in dogs. It is often
  not reversible.
• Skin reactions may be seen.
• Thrombocytopenia and Leukopenia in small animals
  can occur.
• Crystalluria can occur which can damage renal
  tubules and lead to renal failure.
• Carnivores are more likely than herbivores.
• Likeliness increases if dehydrated
• Oral sulfa can cause salivation in cats if tablet
  breaks in mouth.

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LINCOSAMIDES

• Clindamycin (Antirobe), lincomycin (Lincosin)
• Bacteriostatic or bactericidal by affecting
  protein synthesis. Action depends on
  concentration at infection site.
• Gram , anaerobes, and Toxoplasma
• Contraindicated to use in horses, ruminants,
  hamsters, guinea pigs, rabbits. Can cause serious
  GI issues and death.
• Clindamycin is often used for dental infections,
  deep pyodermas, accesses, bite wounds,
  osteomyelitis

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MACROLIDES

• Erythromycin, azithromycin (Zithromax),
  tilmicosin (Micotil), tylosin (Tylan)
• Tylosin and tilmicosin are primarily used in
  cattle.
• Bacteriostatic by inhibiting protein synthesis
• Stimulates intestinal motility so cramping is
  common
• Erythromycin can cause fatal diarrhea in horses

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METRONIDAZOLE

• AKA Flagyl
• Bactericidal, possibly by effecting DNA synthesis
• Effective against protozoa, including Giardia and
  Trichomonas. Good for treating infections in
  bowel or deep wounds.
• Neurological side effects can be seen with high
  doses or prolonged treatment.

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CHLORAMPHENICOL

• Low concentrations are bacteriostatic, high are
  bactericidal
• Disrupts protein synthesis
• Cannot be used in food animals
• Can cause aplastic anemia in humans
• Avoid inhaling powder, wash hands, wear gloves

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ANTIFUNGALS

• GRISEOFULVIN oral med used to treat
  dermatophytes (ringworm)
• Known for being teratogenic in cats. Do not use
  in pregnant animals. Use caution when handling if
  pregnant.
• AMPHOTERICIN B IV med for deep or systemic
  infections
• Rapid onset of action
• Nephrotoxicity is extremely common and dose
  related. Monitor BUN and creatinine every time.

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ANTIFUNGALS

• AZOLES oral (ketoconazole, itraconazole, and
  fluconazole) or topical (miconazole,
  clotrimazole) meds for deep or systemic
  infections
• Usually used before Amphotericin B because side
  effects are fewer
• Topical meds are used for dermatophytosis,
  topical yeast infections
• GI side effects are common with oral meds
• Hepatotoxicity is an issue with ketoconazole