Antibacterial Drugs in Veterinary Dermatology Flashcards
how common is bacterial pyoderma in the dog? cat?
- Bacterial pyoderma is one of the most frequently encountered skin diseases in the dog
- second most common presenting dermatological complaint (the first is “not determined”!)
- Other than abscesses, it is a much less common reason for presentation in the cat.
what is a recurrent pyoderma?
Recurrent pyodermas appear to resolve with treatment only to relapse when the treatment is completed
- recurrent when relapse is within 1-2 months of apparent clinical cure, or if relapse is on a seasonal basis
What are the causes of recurrent pyoderma?
- Underlying causes leading to deficiencies in the defence mechanisms of the skin – endocrine, cutaneous, metabolic or immunologic abnormality are the classic examples.
- Immunodeficiency syndromes are quite rare.
- how common is allergic dermatitis as an underlying condition for pyoderma?
- what bacteria preferentially colonize? why? when do they produce toxins?
- allergenic dermatitis underlying etiology of 67% of pyoderma cases
- atopic dermatitis creates an opportunity for Staph, esp. S. pseudointermedius to create a biofilm
> Staph increased adherence to corneocytes
> also staph particularly benefit from decreased barrier lipid function in atopic dermatitis - once ‘quorum sensing’ population reached, bacteria switch from proliferatin to toxin production, further reducing barrier dunction of the colonized skin
Pharmacological considerations of a poor response to the treatment for pyoderma could include:
- failure to treat underlying cause
- dose (consider the concept of mutant prevention concentration)
- duration
> The surface heals more rapidly than the deeper tissues. Treat for 1-2 weeks
past the point where lesions can no longer be palpated - frequency
> Antibiotic properties must be kept in mind. Some drugs are concentration
dependant; typically, they are once daily treatment while other drugs are time dependant and are typically used more frequently
what part of the bacterium do beta-lactams target?
Cell wall
what antibiotics attack bacterial ribosomes?
- clindamycin
- chloramphenicol
- tetracycline
- aminoglycosides
which antibiotics attack the folic acid synthesis pathway
potentiated sulfonamides
which antibiotics attack bacterial DNA
fluoroquinolone
which anitbiotics attack bacterial rna
rifampin
Amoxicillin Clavulanate
- what category of antibiotics?
- toxicity
- dose
- beta-lactam
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Toxicity: - adverse GI effects
- hypersensitivities (not dose dependent, cutaneous adverse reaction, fever)
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Dose: - Most dermatologists dose this drug at approximately 20 mg per kg (based on amoxicillin)
cephalexin
- category of drug
- toxicity
- beta-lactam
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Toxicity: - GI adverse effects
- hypersensitivities
cefpodoxime
- type of drug
- dose
- beta-lactam
- 5-10 mg/kg q24h PO
> Once daily
> (I usually try to dose cefpodoxime closer to the 10 mg/Kg dose) - 3rd generation
Cefovecin
- type of drug
- dose, timing
Beta lactam, Cephalosporin
- long-acting (non-depot)
- 3rd generation
- Cefovecin is licensed to last 56 days after reconstitution. Colour change will occur during that time and is not reflective of drug activity/safety
what beta lactam drugs are commonly used in veterinary dermatology? which are first, second, thirds line, and last resort?
ALL FIRST LINE:
- amoxicillin-clavulanate
- cephalexin
- cefpodoxime
- cefovecin