Pharmacology: Antimicrobials Classification

General Concepts

• Pathogen: Microorganism causing disease targeted by antimicrobials.
• Culture and Sensitivity:
  • Culture: Identifies the organism.
  • Sensitivity: Identifies effective antimicrobials.
• Gram Stain: Identifies characteristics of pathogen cell wall, aiding antibiotic choice.
• Spectrum:
  • Broad Spectrum: Effective against multiple pathogens.
  • Narrow Spectrum: Effective against specific pathogens.
• Superinfection: Secondary infection from antimicrobial treatment disrupting normal flora.
• Terms:
  • Bacteriostatic: Slows pathogen reproduction.
  • Bactericidal: Kills organism directly.
• Mechanism of Action: How the drug works.
• Drug Resistance: Pathogens mutate and develop resistance, necessitating cautious use of antimicrobials.

Drug Classes

Penicillin

• Mechanism: Bactericidal; attacks bacterial cell wall.
• Spectrum: Generally broad, some subgroups more specific.
• Common Reactions: GI upset, potential for superinfections, hyperkalemia, allergic reactions.
• Nursing Considerations: Monitor for allergies, culture before first dose, take on an empty stomach, monitor clotting mechanisms.

Cephalosporins

• Mechanism: Bactericidal; similar to penicillin
• Spectrum: Broad, various subclasses for specific pathogens.
• Side Effects: Similar to penicillin, nephrotoxicity, and clotting issues.
• Nursing Considerations: Renal impairment caution, seizure disorder caution, culture before first dose.

Macrolides

• Mechanism: Bacteriostatic; inhibits RNA synthesis.
• Uses: Respiratory infections, otitis media, chlamydia.
• Side Effects: GI upset, hypersensitivity, photosensitivity, liver damage.
• Nursing Considerations: Monitor for infection signs, can be taken with food.

Aminoglycosides

• Mechanism: Bactericidal; inhibits protein synthesis.
• Uses: Severe infections like TB, endocarditis.
• Toxicity: High risk for nephrotoxicity, neurotoxicity, ototoxicity.
• Nursing Considerations: Monitor drug levels, peak and trough levels, inject in large muscle, use gloves when handling.

Fluoroquinolones

• Mechanism: Bactericidal; inhibits DNA replication.
• Uses: Pneumonia, complex UTIs, and skin infections.
• Black Box Warning: Tendonitis, tendon rupture, CNS effects.
• Nursing Considerations: Hydrate, monitor for hypoglycemia, administer IV over at least an hour.

Sulfonamides

• Mechanism: Bacteriostatic; broad-spectrum.
• Uses: UTIs, ear infections, bronchitis, traveler's diarrhea.
• Side Effects: Hypersensitivity, potential kidney impairment.
• Nursing Considerations: Caution with type 2 diabetics, monitor glucose and anticoagulant interactions.

Tetracyclines

• Mechanism: Bacteriostatic; inhibits protein synthesis.
• Uses: Broad spectrum for various infections.
• Side Effects: GI upset, photosensitivity, superinfections.
• Nursing Considerations: Avoid use in children under 8 and pregnancy, monitor for CNS issues, avoid dairy and iron products.

Antivirals

• Mechanism: Inhibit virus reproduction, not cure.
• Common Traits: Toxic to the nervous system, require specific timing for effectiveness, monitor kidney function.
• Uses: Specific to virus types (e.g., influenza, COVID).
• General Reaction: Toxicity varies, dosing and compliance critical.