Linezolid Dosing in Pediatric Patients with Renal Impairment
For pediatric patients with renal impairment, the standard linezolid dose of 10 mg/kg every 8 hours (not to exceed 600 mg/dose) can be maintained as no dosage adjustment is required based on renal function. 1
Standard Pediatric Dosing Recommendations
The Infectious Diseases Society of America (IDSA) recommends the following linezolid dosing for pediatric patients:
- Children <12 years: 10 mg/kg/dose PO/IV every 8 hours, not to exceed 600 mg/dose 2
- Children ≥12 years: 10 mg/kg once daily or 600 mg PO/IV twice daily 2
Pharmacokinetics in Renal Impairment
Linezolid has several important pharmacokinetic properties that explain why dose adjustment is not required in renal impairment:
- Approximately 35% of linezolid is excreted unchanged in urine 1
- The remaining 50% is metabolized to two inactive metabolites 1
- Linezolid plasma concentrations in patients with mild to severe renal impairment are similar to those in patients with normal renal function 1
Special Considerations for Pediatric Patients with Renal Impairment
While standard dosing can be maintained, there are important monitoring considerations:
- Use with caution in patients with severe renal insufficiency, as exposure to the two primary metabolites is 7-8 fold higher than in patients with normal renal function 1
- Monitor for thrombocytopenia which occurs more frequently in patients with renal impairment receiving standard linezolid doses 3
- Consider therapeutic drug monitoring (TDM) when available, especially for extended treatment courses (>10 days) 4
Age-Related Pharmacokinetic Differences
Linezolid pharmacokinetics vary by age, which is important to consider alongside renal function:
- Children <12 years have faster clearance and shorter elimination half-life than adults 5
- Clearance decreases gradually among young children, becoming similar to adult values by adolescence 5
- Neonates initially have clearance rates similar to adults, but clearance increases rapidly during the first week of life 5
Monitoring Recommendations
For pediatric patients with renal impairment receiving linezolid:
- Perform baseline complete blood count (CBC)
- Monitor CBC monthly while on linezolid therapy 2
- Screen monthly for peripheral neuropathy 2
- Consider TDM when available, especially for patients with severe renal impairment or those requiring extended treatment courses 4
Potential Adverse Effects
Be vigilant for linezolid-related adverse effects, which may be more common in patients with renal impairment:
- Thrombocytopenia (more frequent in renal impairment) 3
- Peripheral neuropathy
- Myelosuppression
Conclusion
While linezolid dosing does not require adjustment based on renal function in pediatric patients, careful monitoring is essential, particularly in those with severe renal impairment receiving extended courses of therapy.