Linezolid Dosage
For adults, administer linezolid 600 mg PO or IV every 12 hours; for pediatric patients birth through 11 years, administer 10 mg/kg PO or IV every 8 hours (not to exceed 600 mg/dose); for adolescents 12 years and older, use the adult dose of 600 mg every 12 hours. 1
Adult Dosing
The standard adult dose is 600 mg every 12 hours, administered either orally or intravenously 2, 1. This dosing applies across multiple infection types including:
- Complicated skin and soft tissue infections (10-14 days duration)
- Community-acquired and nosocomial pneumonia (14-28 days)
- Bone and joint infections (variable duration)
- Central nervous system infections including meningitis
No dose adjustment is needed when switching between IV and oral routes due to linezolid's 100% oral bioavailability 1. The drug can be administered without regard to meals, though high-fat food delays peak concentration by approximately 40 minutes and reduces Cmax by 17% without affecting total exposure 1.
Pediatric Dosing
Pediatric dosing is age-stratified due to developmental differences in drug clearance 1:
Birth Through 11 Years
- 10 mg/kg every 8 hours (PO or IV)
- Maximum single dose: 600 mg
- This more frequent dosing (q8h vs q12h in adults) compensates for the 2-3 fold higher clearance in younger children 1, 3
Adolescents ≥12 Years
- 600 mg every 12 hours (adult dosing)
Special Neonatal Considerations
Preterm neonates <7 days old (gestational age <34 weeks) should be initiated at 10 mg/kg every 12 hours due to lower systemic clearance. Consider advancing to every 8 hours if clinical response is suboptimal. All neonates should receive every 8-hour dosing by 7 days of life 1.
Duration of Therapy
Treatment duration varies by infection type 2, 1:
- Uncomplicated SSTI: 10-14 days
- Complicated SSTI: 10-14 days
- Pneumonia: 14-28 days
- Bone/joint infections: Variable, individualized based on clinical response
- Bacteremia/endocarditis: 14-28 days minimum
Critical Dosing Considerations
Renal Impairment
No dose adjustment required for any degree of renal insufficiency, as parent drug pharmacokinetics remain unchanged 1. However, inactive metabolites accumulate with worsening renal function. For hemodialysis patients, administer linezolid after dialysis since approximately 30% is removed during a 3-hour session 1.
Hepatic Impairment
No dose adjustment needed for mild to moderate hepatic impairment 4.
Pharmacokinetic Targets
Recent research suggests the current pediatric dosing (10 mg/kg q8h = 30 mg/kg/day) may be inadequate for pathogens with MIC ≥2 mg/L 3, 5. For such organisms, doses of 35-45 mg/kg/day may be required to achieve the target AUC24/MIC ratio ≥100, though this exceeds FDA-approved dosing 5.
Safety Monitoring
Thrombocytopenia risk increases substantially with treatment duration beyond 10-14 days 6. The mechanism involves inhibition of platelet precursor cell synthesis at linezolid concentrations around 8 mg/L 6. Key monitoring points:
- Baseline platelet count strongly predicts risk—lower baseline increases toxicity probability
- Risk is similar between 14 and 28 days of therapy (both high-risk)
- 5-7 day courses carry substantially lower thrombocytopenia risk than longer durations 6
- Monitor complete blood counts weekly during therapy, especially beyond 10-14 days
Common Adverse Effects in Pediatrics
The most frequent adverse events in children include diarrhea (7.8-10.8%), vomiting (9.4%), fever (14.1%), and headache (6.5%) 7. These occur at similar or lower rates compared to comparator antibiotics.
Route of Administration
IV infusion should be administered over 30-120 minutes 1. Do not mix linezolid with other medications in the same line—physical incompatibilities occur with amphotericin B, diazepam, phenytoin, and trimethoprim-sulfamethoxazole among others 1.