AMDs and Antifungals Flashcards
what is the MoA of Penicillins
inhibits cell wall synthesis
what are the main adverse effects of penicillins (3)
1) decrease seizure threshold
2) can cause fatal colitis in hindgut fermenters if given orally
3) hypersensitivities (not given topically)
what are the main PK features of penicillins (3)
1) penicillin G is not acid stable
2) amoxicillin has an oral bioavailability of 90%
3) excreted intact in the urine
how should we be treating penicillins
1) Penicillin G and amoxicillin
2) Potentiated penicillins
what is the general spectrum of Penicillin G
G+ aerobes, anaerobes
what is the general spectrum of amoxicillin
G+ aerobes, anaerobes, some G- aerobes
all penicillins end in
“cillin”
do penicillins have a long or short half life
short (<2h)
what is the Vd (high or low) of penicillins and why
low; they distribute to extracellular fluids well (not brain or prostate) but have poor penetration of cells
if an animal is hypersensitive to penicillins they are also likely reactive to
cephalosporins
what is the MoA of cephalosporins
inhibit cell wall synthesis
what are the major adverse effects of cephalosporins
hypersensitivity; colitis in hindgut fermenters if given orally; reduce seizure threshold
how should we use cephalosporins
first line: 1st gen
second line: 3rd gen
what are the major PK features of cephalosporins
- most are not acid-stable
- some 3rd gen (cefotaxime) enter CNS readily
- not destroyed by penicillinases (may be destroyed by β-lactamases)
what is the general spectrum of first generation cephalosporins
same as amoxicillin: G+ aerobes, anaerobes, some G- aerobes
what is the issue with cefovecin (Convenia)
it is a third generation cephalosporin given as a single SQ injection with a 2-week half-life that essentially guarantees inappropriate duration of therapy
what is a convenient (hint) AMD we should avoid using unless the patient is really aggressive or long duration of therapy needed
Cefovecin (Convenia)
what are the main uses of aminoglycosides
1) topical infections (ex. staph)
2) serious G- aerobic systemic infections
what is the MoA of aminoglycosides
inhibits protein synthesis; bactericidal
what are the major adverse effects of aminoglycosides
nephrotoxicity and ototoxicity
what are the major PK features of aminoglycosides
highly ionized so no oral or topical absorption; food residues are over 1y if given parenterally
how should we give aminoglycosides
1st line: topical administration
2nd line: systemic administration
what is the general spectrum of aminoglycosides
G- aerobes; mycoplasma; staph
what is the MoA of tetracyclines
inhibit protein synthesis (bacteriostatic)