Infection Pharm Flashcards
1
Q
What are the 3 types of classification systems for antimicrobials?
A
- By susceptible organism (narrow vs broad spectrum)
- By bacteriocidal vs bacteriostatic (cidal = lethal to bacteria and static = slow bacterial growth, don’t cause cell death but will ultimately eliminate organism)
- By mechanism of action
2
Q
What are the 4 antimicrobial mechanisms of action?
A
- Cell wall synthesis inhibitors
- Protein synthesis inhibitors
- DNA synthesis inhibitors
- Metabolism inhibitors (folate antagonists)
3
Q
Beta-Lactam Structure
A
- Very similar among penicillins and cephalosporins
- Only difference is R3 at 3-position on cephalosporin
4
Q
MOA of cell wall synthesis inhibitors
A
- Inhibit transpeptidase: enzyme critical to cell wall synthesis, catalyzes formation of cross bridges btw peptidoglycan strand forming cell wall
- Activation of autolysins: enzymes that clave bonds in the cell wall
5
Q
Beta-Lactamase Mechanism of Resistance
A
- Some bacteria produce beta-lactamase: enzyme that destroys antibiotic beta-lactam ring and renders antibiotic ineffective
- Some beta-lactamases are specific to penicillins and cephalosporins
6
Q
Beta-Lactamase Inhibitors
A
- Chemical compound that doesn’t have antimicrobial therapy on its own, but prevents inactivation by beta-lactamase when combined with antibiotic
7
Q
4 categories of Penicillins
A
- Natural PCNs
- Aminopenicillins
- Penicillinase-resistance PCN
- Extended-spectrum PCN
8
Q
Cephalosporins
A
- Grouped into generations according to effectiveness against different organisms, characteristics, development
- Because similar to PCN, cross sensitivity can occur in 5% of patients
9
Q
Cephalosporin Generations
A
- 1st through 5th generations
- Gram + coverage -> Gram - coverage -> broad spectrum
- Better resistance to B-lactamases develops with higher generations
10
Q
Amoxicillin (Amoxil)
A
- Classification: Aminopenicillin, Broad spectrum
- Use: useful against Gram +, Gram - organisms and some anaerobic coverage
- MOA: Cell wall synthesis inhibitor
- Adverse Effects: hypersensitivity reactions, diarrhea
- Drug interactions: caution with oral contraceptive use
- Nursing considerations: renally eliminated so adjust dose in renal dysfunction, may take with food
- Adult dose: 250-500 mg Q8h
- Peds dose: 20-90 mg/kg/day
11
Q
Amoxicillin + clavulanic acid (Augmentin)
A
- Classification: Aminopenicillin, Beta-Lactamase inhibitor
- Use: useful against G+ and G- and some anaerobic organisms, Extends spectrum to cover organisms that are Beta-lactamase producing (H. influenzae)
- MOA: cell wall synthesis inhibitor
- AE: Hypersensitivity reactions, diarrhea
- Nursing considerations: Renally eliminated (adjust dose in renal dysfunction), may take with food
- Adult dose: 250-1000 mg Q8-12h
- Peds dose: 20-90 mg/kg/day
12
Q
Piperacillin + tazobactam (Zosyn)
A
- Classification: Extended-spectrum Penicillin, Beta-lactamase inhibitor, antipseudomonal penicillin
- Use: broad spectrum G-, G+, anaerobes (covers Pseudomonas acruginosa)
- MOA: cell wall synthesis inhibitor
- AE: hypersensitivity reactions, diarrhea
- Nursing considerations: Not available orally, adjust dose in renal dysfunction
- Dose: 2.25-4.5 g IV Q6h
13
Q
Cephalexin (Keflex)
A
- Classification: Oral 1st gen cephalosporin
- Use: mainly active against G+ (skin flora)
- MOA: cell wall synthesis inhibitor
- AE: nausea/vomiting, diarrhea
- Nursing considerations: may take with food, renally eliminated (adjust dose w renal dysfunction)
- Adults dose: 250-1000 mg Q6-8h
- Peds dose: 25-50 mg/kg/day
14
Q
Ceftriaxone (Rocephin)
A
- Classification: 3rd gen cephalosporin
- Use: Some G+ and G- coverage, not good for S. aureus or enterococcus, excellent strep. pneumoniae and N. gonorrhoeae coverage, great CNS penetration
- MOA: cell wall synthesis inhibitor
- AE: hypersensitivity reaction, may increase bleeding tendencies
- Contraindications: avoid in neonates (can displace bilirubin from albumin binding sites), concomitant use with IV calcium-containing solutions/products before 28 days
- Adults dose: 250 mg - 2 g IV/IM Q12-24h
- Peds dose: 50-100 mg/kg/day
15
Q
Azithromycin
A
- Classification: Macrolides class protein synthesis inhibitor, Bacteriostatic and can become Bacteriocidal at high concentrations, Broad spectrum antibiotic
- Use: Reversibly binds to 50s ribosomal subunit inhibiting protein synthesis, covers atypical organisms (mycoplasm, legionella, chlamydia species)
- MOA: protein synthesis inhibitor
- AE: N/V, abdominal pain, some risk of QT prolongation on EKG
- Adult dose: 250-500 mg IV/PO daily
- Peds dose: 5-10 mg/kg/dose IV/PO daily