Antibiotics

  • Amoxicillin
  • Azithromycin
  • Doxycycline
  • Vancomycin

Amoxicillin

  • Mechanism of Action: Beta-lactam antibiotic; inhibits bacterial cell wall synthesis.
  • Indications: Typically used for otitis media, strep pharyngitis, sinusitis, and community acquired pneumonia. 
  • Contraindications: allergy to class/drug
  • Dosage: General: 500 – 1000 mg q12h x 10 days 
  • Half-Life: 30 – 90 minutes
  • Adverse Reactions: Common reactions: nausea, vomiting, diarrhea, rash. Serious reactions: anaphylaxis, SJS/TEN, hypersensitivity vasculitis.
  • Special Considerations: N/A
Video Credit: JJ Medicine

*Deep Dive: Amoxicillin (Drugs.com)



Azithromycin

  • Mechanism of Action: Macrolide antibiotic; 
  • Indications: community-acquired pneumonia, sinusitis, pharyngitis, COPD exacerbations, and genital infections.
  • Contraindications: allergy/hypersensitivity to macrolides
  • Dosage: Typically a tapered dose of 500 mg PO on day 1, then 250 mg PO x 4 days). Often a single 1-2 gram dose for sexually transmitted infections.
  • Half-life: 68 hours
  • Adverse Reactions: vomiting, diarrhea, headache, vision changes. May also cause prolonged QT or hepatic necrosis.
  • Special Considerations: None
Video Credit: Medicosis Perfectionales

*Deep Dive: Should we Stop Prescribing Azithromycin in the ED? (REBEL EM)



Doxycycline

  • Mechanism of Action: Tetracycline; inhibits bacterial protein synthesis after specific ribosomal binding
  • Indications: Community-acquired pneumonia, cellulitis, bacterial sinusitis, chlamydia/gonorrhea, PID, lyme disease
  • Contraindications: Allergy to drug/class, pregnancy, Age < 8 years old (due to teeth staining, although short courses are permissible)
  • Dosage: Generally 100mg PO/IV daily or q12 hours x 7 days
  • Onset: Peak concentration after 2-4 hours
  • Duration: Half life of 18 hours
  • Adverse Reactions: Headache, nausea, dyspepsia, tooth discoloration (controversial), C. Diff diarrhea
  • Special Considerations: None
Video Credit: Pharmacist Conversations

*Deep Dive: Doxycycline (Drugs.com)



Vancomycin

  • Mechanism of Action: Glycopeptide antibiotic; inhibits cell wall synthesis, exhibiting a bactericidal action. Very potent against gram-positive bacteria. 
  • Indications: Sepsis, MRSA skin and soft tissue infections, endocarditis, meningitis, C difficile colitis
  • Contraindications: Allergy to class/drug
  • Dosage: Initial loading dose generally 15-20mg/kg IV. Maintenance dose is 500-1000 IV q12 hours.
  • Onset: Rapid
  • Duration: Half life of 4-6 hrs
  • Adverse Reactions: Hypotension (with rapid IV use), “red man syndrome”,  nausea
  • Special Considerations: None
Video Credit: Simple Nursing

*Deep Dive: Is vancomycin/zosyn the answer for everything? (emDocs)


Brandon Simpson, PA-S2
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