Everything Azithromycin.

1️⃣ Azithromycin (Zithromax, Zmax)

Class: Macrolide antibiotic (50S inhibitor). MOA: Inhibits bacterial protein synthesis → bacteriostatic/cidal by concentration. Use: Respiratory infections (strep pharyngitis, pneumonia), STIs (gonorrhea, chancroid), and MAC prophylaxis in advanced HIV. Contra: Hypersensitivity, prior cholestatic jaundice, QT prolongation, hypokalemia, or bradycardia → risk of Torsades de Pointes. Adverse / Interventions:

• QT Prolongation / Arrhythmia: Monitor cardiac status; avoid QT-prolonging drugs (quinidine, amiodarone).
• Hepatotoxicity / Cholestasis: Monitor LFTs (AST, ALT, LDH).
• SJS / TEN / Anaphylaxis: Stop immediately at first rash or swelling.
• C. Diff Diarrhea: Monitor stool frequency and hydration. Priority: Stop for severe skin reaction or anaphylaxis; watch for dysrhythmias.

2️⃣ Aztreonam (Azactam, Cayston)

Class: Monobactam β-lactam antibiotic. MOA: Bactericidal; binds cell-wall membrane → cell lysis. Use: Serious gram-negative infections (including Pseudomonas and multi-resistant strains). Contra: Hypersensitivity to aztreonam. Adverse / Interventions:

• Hypersensitivity / Anaphylaxis: Assess rash, wheezing, edema; notify HCP immediately.
• Superinfection (oral/vaginal candidiasis): Educate patient to report itching or discharge.
• Drowsiness/Dizziness: Caution with driving or machinery. Priority: Stop drug and treat if anaphylaxis occurs (fever, chills, dyspnea).

3️⃣ Azathioprine

Class: Immunosuppressant / DMARD. MOA: Antimetabolite that suppresses T-cell activity → ↓ immune response (prevents graft rejection). Use: Prevention of transplant rejection; treatment of rheumatoid arthritis. Contra: Severe infection or known hypersensitivity (others not specified). Adverse / Interventions:

• Bone Marrow Suppression: Monitor CBC and platelets; dose ↓ if < 3000 platelets.
• Hepatotoxicity: Monitor LFTs and bilirubin; report jaundice.
• GI Upset: Take with food to reduce nausea. Priority: Bone-marrow suppression = life-threatening → monitor labs and infection signs (fever, fatigue, bleeding, chills).

🔥 Rapid Recall Summary

• Azithromycin: Watch for QT prolongation & liver toxicity. Stop if rash or arrhythmia.
• Aztreonam: Kills Gram-negatives hard; monitor for anaphylaxis & superinfection.
• Azathioprine: Suppresses immune system; monitor CBC & LFTs—bone marrow and liver are targets.

Mnemonic: 💊 Three A’s — Airway, Allergy, Anemia → Cardiac for Azithro, Anaphylaxis for Aztreo, Anemia for Azathioprine.