From the FDA Drug Label
No dosage adjustment is recommended for subjects with renal impairment (GFR ≤80 mL/min) The mean AUC0-120 was similar in subjects with GFR 10 to 80 mL/min compared to subjects with normal renal function, whereas it increased 35% in subjects with GFR <10 mL/min compared to subjects with normal renal function. Caution should be exercised when azithromycin is administered to subjects with severe renal impairment.
Prescribing Azithromycin to a Patient with Impaired Renal Function (GFR of 20)
- No dosage adjustment is recommended for patients with a GFR of 20, as the mean AUC0-120 was similar in subjects with GFR 10 to 80 mL/min compared to subjects with normal renal function.
- However, caution should be exercised when administering azithromycin to patients with severe renal impairment, as the drug's pharmacokinetics may be altered.
- It is essential to monitor the patient closely for any adverse effects or changes in renal function while taking azithromycin 1.
From the Research
No dosage adjustment of azithromycin is required for patients with impaired renal function, including those with a GFR of 20 mL/min. The standard adult dosing can be used: typically 500 mg on day 1, followed by 250 mg daily for days 2-5 for most infections, or a single 1-gram dose for certain conditions like chlamydia. Azithromycin is primarily eliminated through biliary excretion with minimal renal clearance (less than 10% of the dose is excreted unchanged in urine), making it a safe choice for patients with kidney dysfunction, as supported by a study published in 1995 2. Unlike many other antibiotics, azithromycin's pharmacokinetics remain largely unaffected by decreased renal function. However, it's essential to monitor for potential side effects such as QT prolongation, especially if the patient is on other medications that may affect cardiac conduction. Liver function should also be considered since azithromycin undergoes hepatic metabolism, so caution is advised in patients with significant hepatic impairment. Key points to consider when prescribing azithromycin to patients with impaired renal function include:
- Monitoring for signs of toxicity or adverse effects
- Being aware of potential drug interactions, particularly those that may affect cardiac conduction
- Considering the patient's overall health status and adjusting the treatment plan as necessary
- Keeping in mind that azithromycin's pharmacokinetics are not significantly altered in patients with renal insufficiency, as demonstrated in a study published in 1995 2.