Beta-Lactams

Question 1

Beta-lactam drugs

Answer 1

Penicillins
Cephalosporins
Carbapenems
Monobactams

Question 2

What is essential about the structure of beta-lactams?

Answer 2

Beta-lactam ring

Question 3

General classifications of Penicillins

Answer 3

Natural: Penicillin G
Amino: Ampicillin, Amoxicillin
Anti-Staphylococcal: Oxacillin
Entended Spectrum: Piperacillin

Question 4

Beta-lactam MOA

Answer 4

Prevention of cell wall formation and lysis of bacterial cells
-Bactericidal for growing cells

Question 5

Dosing for Beta-lactams

Answer 5

Time dependent
Lower dose, more frequently

Question 6

Paradoxical effect for beta-lactams

Answer 6

Concentrations above optimal killing conc result in reduced bactericidal effect due to growth arrest: need a growing cell to kill

Question 7

Resistance to beta-lactams

Answer 7

Beta-lactamase enzymes produced by bacteria
-Need to add beta-lactamase inhibitory drugs

Question 8

Beta-lactamase inhibitors

Answer 8

A way to block resistance via beta-lactamase enzymes
Clavulanic acid
Avibactam
Tazobactam
Commonly mixed w/ beta lactams

Question 9

PK properties of penicillins

Answer 9

Poor oral absorption
Short half-life/rapid elimination
Small vol of distribution
Renal elimination

Question 10

Penicillin G

Answer 10

Mostly active against gram + aerobes and anaerobes, less activity against staph, gram -, and E coli
Hypersensitivity rx most common side effect

Question 11

What species are susceptible to procain tox?

Answer 11

Birds
Snakes
Turtles
Guinea Pigs
Chinchillas

Question 12

What is the drug of choice for mixed aerobic-anaerobic infections, such as cat bites?

Answer 12

Ampicillin or amoxicillin

Question 13

What is the drug of choice for treating UTIs and lepto?

Answer 13

Amoxicillin

Question 14

Which penicillin is inherently more resistant to beta-lactamase enzymes?

Answer 14

Cephalosporins

Question 15

How does activity change as cephalosporins increase in generation?

Answer 15

As generation increases (1 to 4) the gram - coverage increases, but at the cost of gram + coverage

Question 16

What is ceftiofur used for?

Answer 16

Resp disease of cattle, sheep, swine and horses
UTIs in dogs

Question 17

How is Convenia/Cefovecin used?

Answer 17

3rd generation Cephalosporin used in dogs and cats. Long lasting treatment, one injection remains above MIC level for 14 days for staph.

Question 18

What is concerning about the use of cephalosporins?

Answer 18

3 and 4 gen should not be used as first line. Narrowest spectrum should be chosen first.
Convenia is used often just because it is easy.

Question 19

What does Imipenem do?

Answer 19

Carbapenem: widest activity of any antibiotic
Always administered with cilastatin to prevent nephrotoxicity
Should not be used as first line to prevent resistance