Infection Pharm Flashcards

1
Q

What are the 3 types of classification systems for antimicrobials?

A
  1. By susceptible organism (narrow vs broad spectrum)
  2. By bacteriocidal vs bacteriostatic (cidal = lethal to bacteria and static = slow bacterial growth, don’t cause cell death but will ultimately eliminate organism)
  3. By mechanism of action
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2
Q

What are the 4 antimicrobial mechanisms of action?

A
  1. Cell wall synthesis inhibitors
  2. Protein synthesis inhibitors
  3. DNA synthesis inhibitors
  4. Metabolism inhibitors (folate antagonists)
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3
Q

Beta-Lactam Structure

A
  • Very similar among penicillins and cephalosporins

- Only difference is R3 at 3-position on cephalosporin

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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
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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
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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
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7
Q

4 categories of Penicillins

A
  • Natural PCNs
  • Aminopenicillins
  • Penicillinase-resistance PCN
  • Extended-spectrum PCN
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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
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9
Q

Cephalosporin Generations

A
  • 1st through 5th generations
  • Gram + coverage -> Gram - coverage -> broad spectrum
  • Better resistance to B-lactamases develops with higher generations
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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
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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
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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
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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
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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
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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
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16
Q

Doxycycline

A
  • Classification: Tetracycline class protein synthesis inhibitor, Bacteriostatic broad spectrum antibiotic
  • Use: Treats G+ and G-, activity against mycoplasma pneumoniae, chlamydia species, tick-borne illness
  • MOA: protein synthesis inhibitor
  • AE: phototoxicity, tooth discoloration (avoid in pregnancy or children less than 8 yrs), associated with development of C diff associated diarrhea
  • Drug interactions: binds to cations (avoid admin with milk, antacids, etc), oral contraceptives
  • Nursing considerations: separate 2+ hours from cation ingestion
  • Adult dose: 100 mg IV/PO Q12h
  • Peds dose: 2-4 mg/kg/day IV/PO
17
Q

Metronidazole

A
  • Classification: Bacteriocidal fairly narrow spectrum antibiotic
  • Use: inhibits nucleic acid synthesis and causes cell death, spectrum: protozoa (sytemic amebiasis, trichomoniasis, giardiasis), anaerobic bacteria
  • MOA: DNA synthesis inhibitor
  • AE: nausea, headache, metallic taste, hypersensitivity reactions
  • Drug interactions: ethanol-disulfiram reaction (facial flushing, vomiting, dyspnea, tachycardia), CYP 3A4 substrate (warfarin, phenytoin, phenobarbital, rifampin, cyclosporine, tacrolimus)
  • Adult dose: 250-750 mg IV/PO Q8-12h
  • Peds dose: 22.5-40 mg/kg/day
18
Q

Fluconazole

A
  • Classification: antifungal member of -azole family, fungistatic
  • Use: most commonly used for Candida infections, and subcutaneous/systemic infections
  • MOA: inhibition of CYP450 dependent synthesis of ergosterol, results in damage to cytoplasmic membrane and accumulation of ergosterol precursors
  • AE: nausea, headache, rash, abdominal pain (rare = hepatic necrosis)
  • Drug interactions: inhibition of CYP3A4
  • Adult dose: 200-800 mg IV/PO Q24h or 15 mg POx1
  • Peds dose: 10-12 mg/kg/dose IV/PO Q24h