Clinical beta
FMBM is currently in clinical beta. Content is for professional review/testing and must not replace local protocols, senior clinical judgment, or official prescribing references.
Drug Monograph
Azithromycin
Macrolide (PO, IV)
Indication
CAP β’ pertussis β’ chlamydia/gonorrhea combo β’ COPD exacerbation selected β’ travelerβs diarrhea
INDICATIONS (CORE USE)
Atypical coverage, STIs, some CAP β **QT prolongation**; **drug interactions** via CYP3A/P-gp; **hearing loss** high dose prolonged.
ADULT DOSE (STANDARD)
500 mg PO daily Γ 3d or 5d packs (indication-specific); CAP 500 mg day1 then 250 mg daily
MAX DOSE
1.5 g cumulative some STI regimens β single high doses distinct
Route
PO, IV
PEDIATRIC DOSE
10 mg/kg day1 max 500 mg then 5 mg/kg days 2β5 β verify indication
Must-not-miss safety points
Major warning
- QT prolongation / torsades β check ECG if risk factors + other QT drugs - Hepatotoxicity - Sensory hearing loss with prolonged high exposure - Resistance: pneumococcus/macrolide β donβt rely monotherapy severe pneumococcal pneumonia in high-resistance regions
USE IF: Atypical coverage, chlamydia, pertussis, some CAP per guideline. AVOID IF: Congenital long QT + multiple QT drugs; can use beta-lactam narrower for bacterial sinusitis in many cases.
Primary
Secondary
Other
STANDARD (ADULT PO)
500 mg PO day 1 β 250 mg daily days 2β5 (Z-pack pattern) OR 500 mg Γ3d β match indication
ADULT DOSE
Z-pack vs 3-day vs 5-day β match indication; IV rare severe CAP GI intolerance
PEDIATRIC DOSE
Suspension dosing by weight.
MAX DOSE
~500 mg/day typical after day 1 load; avoid stacking QT-prolonging agents
Practical Note
Food decreases absorption slightly β usually acceptable.
Clinical warnings
Adverse effects
Pediatrics
10 mg/kg day1 max 500 mg then 5 mg/kg days 2β5 β verify indication
Pregnancy
Generally considered acceptable short courses
Lactation
low risk.
Renal impairment
No adjustment oral; severe renal GFR <10 β some guidance extends interval for Zmax β check label. **CrCl scaffold (FMBM β titrate to FDA/SFDA label + institutional pharmacy nomogram):** - **CrCl β₯50** β standard per agent (azithro PO often unchanged) - **CrCl 10β50** β clarithro/erythro β check label for interval/dose; azithro usually minimal change - **CrCl <10** β extend interval or reduce dose per label (Zmax / IV forms β **verify product**)
Hepatic impairment
Severe hepatic impairment β caution.
Elderly
QT risk; drug interactions.
PO with or without food; IV infusion rate per stability.
Clinical Picture
**Life-threatening (first):** **torsades / polymorphic VT** (QT). **Secondary:** GI upset; hearing at extreme exposure.
Immediate Actions
Stop macrolide β ECG; K+/Mg2+ repletion; telemetry if symptomatic
Antidote
No specific antidote; treat complications (e.g. anaphylaxis β epinephrine per ACLS)
Decontamination
Recent large PO β charcoal if appropriate
Escalation
Torsades / unstable VT β **ICU** ACLS; magnesium per protocol; **severe renal failure with accumulation β consider HD** (erythromycin more than azithro) β pharmacy
Common mistakes, resistance logic, and bedside traps
Convenient **atypical + STI** macrolide. **QT + drug interaction** landmine. **Resistance** limits empiric CAP monotherapy in many regions.
Stewardship: acute bronchitis usually viral β no macrolide. Pertussis early treatment matters. Anti-motility in travelerβs diarrhea with caution (toxin producers). *Stewardship (all antimicrobials):* Empiric choice β syndrome severity + **local antibiogram**; shortest effective course.
Long half-life allows short courses; hepatic metabolism.
50S ribosome β inhibits protein synthesis; long tissue half-life.
Saudi Arabia
Zithromax, Azithromycin
Global
Z-Pak, (placeholder β verify local formulary)
Common trade names are curated examples only β formulations and availability vary. Verify the exact product name with your local pharmacy and national regulator before prescribing or dispensing.
Saudi Arabia
International