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# Mycoplasma (Pathogen) Management
## Overview
*Mycoplasma pneumoniae* is an atypical bacterium lacking a cell wall, rendering beta-lactam antibiotics (penicillins, cephalosporins) completely ineffective. Treatment focuses on agents that inhibit protein synthesis (macrolides, tetracyclines, or fluoroquinolones).
## Primary Indications
Treatment of community-acquired pneumonia (CAP) or tracheobronchitis caused by *M. pneumoniae*.
## Adult Dosing
* **Azithromycin:** 500 mg PO on day 1, followed by 250 mg PO daily for days 2–5 (Total 5-day course).
* **Doxycycline:** 100 mg PO twice daily for 5–10 days.
* **Levofloxacin:** 500 mg PO/IV daily for 5–7 days.
* **Moxifloxacin:** 400 mg PO/IV daily for 7 days.
## Pediatric Dosing
* **Azithromycin:** 10 mg/kg (max 500 mg) on day 1, followed by 5 mg/kg (max 250 mg) daily for days 2–5.
* **Doxycycline:** 2.2 mg/kg per dose twice daily (max 100 mg/dose). *Note: Tetracyclines are generally avoided in children <8 years due to dental staining, but short courses for respiratory infection are increasingly supported by AAP/IDSA guidelines when benefits outweigh risks.*
* **Levofloxacin:** For children >6 months: 10 mg/kg/dose (max 500 mg) every 12–24 hours based on age/weight.
## Dose Adjustments
* **Renal/Hepatic:** Macrolides (azithromycin) generally require no adjustments; tetracyclines and fluoroquinolones may require dosage reduction in severe renal impairment (consult institutional protocols for specific CrCl cut-offs).
## Contraindications
* **General:** Known hypersensitivity to the chosen drug class.
* **Fluoroquinolones:** Avoid in patients with a history of myasthenia gravis, aortic aneurysm/dissection risk, or significant QTc prolongation.
* **Tetracyclines:** Caution in pregnancy (second/third trimester) and children <8 years unless alternative agents are ineffective.
## Adverse Effects
* **Macrolides:** GI upset (nausea, diarrhea), QTc prolongation.
* **Tetracyclines:** Photosensitivity, esophageal irritation (take with full glass of water, remain upright), tooth discoloration.
* **Fluoroquinolones:** Tendonitis/tendon rupture, CNS effects (dizziness, confusion), dysglycemia, *Clostridioides difficile*-associated diarrhea.
## Key Drug Interactions
* **Macrolides:** Moderate to strong inhibitors of CYP3A4 (e.g., clarithromycin; azithromycin is a weak inhibitor but monitor with warfarin and digoxin).
* **Tetracyclines/Fluoroquinolones:** Chelation occurs with divalent/trivalent cations (antacids, iron, calcium, magnesium); separate doses by 2–4 hours.
* **QTc Prolongation:** Caution when co-administering macrolides or fluoroquinolones with other QTc-prolonging agents (e.g., ondansetron, amiodarone).
## Monitoring
* Monitor for clinical improvement (fever resolution, respiratory status) within 48–72 hours.
* Assess for adverse effects (e.g., GI symptoms, rash, or signs of tendon involvement).
* Local resistance patterns (increasing in some regions) should guide drug selection.
## Clinical Pearls
* **Macrolide Resistance:** Rates of *M. pneumoniae* macrolide resistance are rising significantly globally; if a patient fails to improve after 48–72 hours of appropriate macrolide therapy, consider switching to a tetracycline or fluoroquinolone.
* **Duration:** Clinical efficacy is often achieved with shorter courses (5 days); avoid unnecessarily prolonged therapy.
* **Empiric Coverage:** In adults, if CAP is severe or community resistance is high, fluoroquinolones or respiratory tetracyclines are preferred over macrolides.
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**Educational Disclaimer:** This information is for educational purposes only. Clinical guidelines and local antimicrobial resistance patterns change frequently. Always verify dosing and indications against current institutional protocols, primary literature, and the official manufacturer's prescribing information before administration.
