Week 10: Beta Lactams - PCNs, Cephalosporins, and Glycopeptides

Question 1

What is the MOA of the penicillins?

Answer 1

Inhibit the biosynthesis of peptidoglycan bacterial cell wall

Question 2

Penicillin V and Penicillin G Benzathine are active against what type of organisms?

Answer 2

Narrow spectrum

gram + mostly: S. pneumoniae, GABHS

bactericidal Pen V (oral) is best for group A beta-hemolytic strep - strep throat/pharyngitis

Pen G (IV) best for syphilis infection (T. pallidum)

Question 3

Amoxicillin and Augmentin (Amox/Clavulanic Acid) are active against what type of organisms?

Answer 3

More broad spectrum

Same gram + organisms as Pen V/Pen G but also some activity against gram - organisms - bactericidal

Amoxicillin - 1st line for AOM, lyme disease < 8 years old, prophylaxis endocarditis, H. Pylori

Augmentin - 1st line fx for bites, UTI in pregnancy, COPD acute exacerbation

Question 4

PCNs cautions/CI

Answer 4

• maculopapular rash = hallmark of allergy (common in amoxicillin: not a true allergic rxn) - Steven Johnson syndrome - anaphylaxis

Question 5

PCNs ADRs

Answer 5

• Rash - GI (N/V/D) - Fungal overgrowth/candidiasis - C diff

Question 6

Cephalosporin MOA

Answer 6

-inhibit mucopeptide synthesis in the bacterial cell wall -Bactericidal

Question 7

Cefazolin (IV) and Cephalexin (Keflex) (PO)

Activity/indications

Answer 7

1st Generation Cephalosporins

• methicillin-sensitive S. aureus (MSSA) S. epidermidis, strep throat - E.coli - used for skin and soft tissue infections - cellulitis, impetigo -Group A Beta Hemolytic Strep (GABHS)

2nd line AOM, strep throat if PCN allergy

Question 8

Cefuroxime, Cefprozil, Cefaclor activity/indications

Answer 8

2nd Generation Cephalosporins

• same as 1st Gen - H. Influenzae (broaden activity as go up generations) -

broader gram - organism coverage

Respiratory tract infections - Lyme dz - uncomp. UTI

Question 9

Ceftriaxone, Cefdinir, Cefpodoxime, Ceftazidime (IV) activity/indications

Answer 9

3rd Generation Cephalosporins

• broader indications
• more gram - organisms: N. gonorrhoeae, H. flu, N. meningitidis
• good CNS penetration
• meningitis, CAP, PID, respiratory tract infections, complicated UTIs (men, pregnancy, post-menopausal women)

Question 10

Cefepime indication

Answer 10

4th Generation Cephalosporins

• reserved for severe infections - against gram + organisms - pseudomonas aeruginosa

Question 11

Ceftaroline

Answer 11

Ceftaroline “-aroline = caroline is 5th place”

5th Generation Cephalosporins

• IV only and for more severe infections
• similar to 3rd generation, except also active against MRSA

Question 12

Cephalosporins ADRs

Answer 12

C. diff

hypersensitivity rx

hemolytic anemia

neutropenia, leukopenia

coagulation abnormalities

Question 13

Cephalosporins cautions/CIs

Answer 13

• hx of PCN allergy with anaphylaxis or hypersensitivity rx -

OK in pregnancy/lactation

NO ceftriaxone in neonates @ risk for hyperbilirubinemia

the stronger the drug (5th generation is strongest; 1st generation is weakest) - the more chance of a C. Diff infection

Question 14

What drug is in the glycopeptide class?

Answer 14

Vancomycin (PO)

Question 15

Vancomycin MOA and indication

Answer 15

• inhibits cell wall synthesis by binding to the D-A1a-D-A1a protein in the cell wall -

oral is not well absorbed - stays in the GI tract - perf for C. diff. infection

Question 16

Vancomycin (oral) ADRs

Answer 16

• ototoxicity - nephrotoxicity - GI (bitter taste, mouth irritation, abd pain, nausea, fatigue) -peripheral edema, h/a

** monitoring for hearing and renal function