Azithromycin Dosing with eGFR 30 mL/min/1.73 m²
Standard adult doses of azithromycin can be used without adjustment in patients with an eGFR of 30 mL/min/1.73 m², as no dose reduction is required until eGFR falls below 10 mL/min/1.73 m². 1
FDA-Approved Dosing Guidance
- The FDA label explicitly states: "No dosage adjustment is recommended for subjects with renal impairment (GFR ≤80 mL/min)" 1
- Dose adjustment considerations only arise when GFR drops below 10 mL/min/1.73 m², where the AUC increases by 35% compared to normal renal function 1
- For patients with eGFR 30 mL/min/1.73 m², the mean AUC remains similar to those with normal renal function 1
Standard Dosing Regimens at eGFR 30
The following standard doses apply without modification 1:
- Community-acquired pneumonia: 500 mg Day 1, then 250 mg daily Days 2-5
- Acute bacterial exacerbations of COPD: 500 mg daily × 3 days OR 500 mg Day 1, then 250 mg daily Days 2-5
- Acute bacterial sinusitis: 500 mg daily × 3 days
- Skin/skin structure infections: 500 mg Day 1, then 250 mg daily Days 2-5
Pharmacokinetic Evidence Supporting No Adjustment
- A dedicated pharmacokinetic study demonstrated that neither the area under the plasma concentration curve, distribution volume (16 L/kg), nor maximal plasma concentration were significantly affected by renal insufficiency across a wide range of renal function 2
- The nonrenal clearance of azithromycin remains unaffected by renal impairment, though tubular drug concentration may increase 2
- Long-term safety data from cystic fibrosis patients using chronic azithromycin showed no decline in eGFR over a cumulative 364.8 patient-years of exposure 3
Important Clinical Caveats
- Severe renal impairment (eGFR <10 mL/min/1.73 m²): Exercise caution due to 35% increase in drug exposure, though no specific dose reduction formula is provided in the FDA label 1
- QTc prolongation risk: Monitor for QTc interval prolongation, particularly when azithromycin is combined with other QTc-prolonging medications, as 10.3% of chronic users showed borderline or prolonged QTc intervals when using concomitant QTc-prolonging drugs 3
- Hepatic impairment: No dose adjustment recommendations exist for hepatic dysfunction, as pharmacokinetics have not been established in this population 1
Practical Application
For your patient with eGFR 30 mL/min/1.73 m², prescribe the standard indication-based dose without modification. The threshold for considering any dose adjustment is eGFR <10 mL/min/1.73 m², which is far below this patient's current renal function 1, 2. This approach is supported by both FDA labeling and pharmacokinetic studies demonstrating preserved drug clearance across moderate renal impairment 1, 2.