Lecture: antibiotics Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

Choice of AB is determined by

A
  • susceptibility of bacteria
    • main target is staph
  • concurrent dz
  • depth of infection
  • length of tx
  • breed
  • age
  • owner constraints
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

General rules for antibiotic therapy

A
  1. Select AB with narrow spectrum
  2. Select AB with wider margin of safety
  3. Try to never combine AB with glucocorticoids
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

AB for pyo

First line

A
  1. Erythromycin
  2. Lincomycin
  3. Clindomycin
  4. First gen cephalosporines
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

AB for pyo

Second line

A
  1. potentiated sulfonamides
  2. third gen cephalosporins
  3. amoxicillin/clavulanic acid
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

AB for pyo

Third line (Big guns)

A
  1. Fluoroquinalones
  2. Chloramphenicol
  3. Rifampin
  4. Amikacin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Erythromicin

A
  1. Macrolide; inhibits ribosomal protein synthesis
  2. Bacteriostatic, Time-dependent (TID)
  3. Narrow spectrum for staph
  4. Vomiting almost a given
  5. Inhibits cytochrome P450
  6. absorption delayed by food administration (inactivated by gastric secretions)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Lincomycin

A
  1. Macrolide-like AB
  2. Bacteriostatic, admin BID
  3. better absorption/distribution, less vomiting than erythromycin
  4. rapid resistance
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Clindamycin

A
  1. Related to lincomycin, BID
  2. Absorption not altered by food
  3. Good penetration in fibrotic tissues
  4. Skin infection dose 11 mg/kg
  5. high effectiveness treating methicillin resistent staph
  6. Well tolerated by most, used frequently for S. schleiferi
    • nosocomial infections in people and dogs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Cephalosporins

A
  • Broad spectrum bacteriacidal
    • inhibits synthesis of bacterial cell wall
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Cephalexin

A
  1. First generation cephalosporin, broad spectrum but mostly Gram +
  2. Adverse affects
    • GI
    • Immune mediated disease
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Details about second line choices

A
  1. Potentiated sulfonamides
  2. Third generation cephalosporins
    • broader spectrum good for mixed infections
  3. Amoxicillin/clavulanic acid
    • will not work for s. pseudointermedius
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Can’t use clavamox if an infection is …

A

methicillin resistent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Potentiated sulfonamides

A
  1. Interfere with synthesis of folic acid
  2. Immunogenic - triggers hypersensitivity
    • type I: IgE mediated (swollen, red)
    • type II: cytotoxic (Immune mediated thrombocytopenia)
    • type III: immune complex deposition (lupus)
  3. Antacids interfere with absorption
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Shifting leg lameness

A

can be adverse affect of sulfas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Potentiated sulfonamides

Adverse affects

A
  • Anemia, leukopenia, thrombocytopenia
  • KCS
  • shifting leg lameness (lupus-like joint symptoms)
  • hypothyroidism
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Two drugs that will affect thyroid levels

A
  • Pred
  • Sulfas
17
Q

Dogs that should not see sulfas

A
  • Black and tan dogs: arthropathy
    • Dobies
    • Rotties
18
Q

Silver sulphadiazine

A
  • topical sulfonamide
  • broad spectrum
  • ideal for Pseudomonas
  • ears and skin
19
Q

Cefovecin (Convenia)

Defpodoxime proxetil (Simplicef)

Third gen cephalosporins

A
  • broader spectrum, active against G-
  • activity against s. pseudointermedius same as first gen
  • potential selection for methicillin resistence
  • Use as a first choice if compliance might be a problem (injectible)
20
Q

Beta-lactamase resistant penicillins

A
  • Oxacillin
  • Dicloxacillin
  • Nafcillin
  • Expensive
  • Excellent for staph
  • TID
21
Q

Amoxicillin/Clavulanic acid

(Clavamox)

A
  • Broad spectrum: primarily Gram +
  • Bacteriocidal
  • Rapid absorption
  • GI side effects
  • Dose: 22 mg/kg BID
  • Expensive for big dogs
22
Q

Chloramphenicol

A
  • Broad spectrum, inhibits ribosomal protein synthesis, bacteriostatic
  • Time-dependent 50 mg/kg TID
  • metabolized by the liver
  • Owners: aplastic anemia
  • anemia in animals is reversal
  • peripheral neuropathy in large breed dogs
23
Q

Fluoroquinalones (Baytril)

A
  • only use in resistant cases as last resort
  • Concentration dependant (use once daily high dose)
  • Absorption inhibited by antacids
  • Great for deep pyo
  • GI, Nuero signs
    • lowers threshold for seizures
24
Q

Enrofloxacin (Baytril)

Fluoroquinalone

A
  • bioconverted to cirpofloxacin
  • Bioavailability: 40%
  • 20 mg/kg once a day
  • expensive
25
Q

Marbofloxacin (Zeniquin)

Fluoroquinalone

A
  • Bioavailability: 94%
  • Dose: 2.75 - 5.5 mg/kg SID
26
Q

Orbifloxacin (Orbax)

Fluoroquinalone

A
  • Bioavailability: 97%
  • Dose: 2.5 mg/kg SID
27
Q

Moxifloxacin

A
  • human product
  • used in dogs at 8 mg/kg SID
28
Q

Pradofloxacin (Veraflox)

A
  • 3rd gen enhanced spectrum vet fluoroquinalone
  • Europe: labeled for dogs; US: labeled for cats
  • b/c baytril can’t be used for cats
  • extensive ocular safety testing
29
Q

bioavailability of cipro versus enrofloxacin

A

enrofloxacin has a more consistent bioavailability

30
Q

Doxycycline

A
  • Time dependent antibiotic: 5-10 mg/kg BID
  • used for resistent cases
  • very expensive, substituted with minocycline
  • anti-inflammatory properties
  • adverse affects
    • GI
    • yellow staining of teeth
    • esophageal strictures
31
Q

Topical AB

Mupirocin

A
  • Excellent for staph infections
  • rare resistance
  • minimal systemic absorption
32
Q

Topical AB

Polymixin B

A
  • Used for resistant Pseudomonas
  • binds to cell membrane and alters structure to make permeable => cell death
33
Q

AB you SHOULD NOT USE

Save for people

A
  1. Vancomycin
  2. Linezolid
  3. Synercid
34
Q

Long term AB therapy

A
  • Not recommended
  • Avoid pulse therapy
  • Consider all triggering factors before considering immune stimulation
35
Q

Conclusion

A
  1. Skin infections are secondary
  2. Try your best to identify underlying cause to avoid repetitive AB course that encourages resistence
  3. narrow spectrum first
  4. culture unresponsive cases before switching