Linezolid Dosing Recommendations
Standard Adult Dosing
The recommended dose of linezolid for adults is 600 mg IV or PO every 12 hours for treating MRSA, VRE, and other serious Gram-positive infections. 1, 2
This standard dosing applies to:
- Nosocomial pneumonia 1
- Community-acquired pneumonia 1
- Complicated skin and skin structure infections 1, 2
- Vancomycin-resistant Enterococcus faecium infections 1, 2
- MRSA bacteremia, osteomyelitis, septic arthritis, and CNS infections 1
Do not reduce the dosing frequency to every 24 hours, as this fails to maintain adequate drug exposure for bactericidal activity. 1
Pediatric Dosing
For children, dosing is weight-based and age-dependent:
- Children under 12 years: 10 mg/kg IV or PO every 8 hours (maximum 600 mg per dose) 1, 2
- Children 12 years and older: 600 mg IV or PO every 12 hours (adult dosing) 1, 2
Treatment Duration by Indication
The Infectious Diseases Society of America provides specific duration recommendations:
- Uncomplicated skin and skin structure infections: 10-14 days 1
- Septic arthritis: 3-4 weeks 1
- CNS infections (meningitis, brain abscess): 2-6 weeks depending on specific infection 1
- Osteomyelitis: Minimum 6-8 weeks, with consideration for additional 1-3 months of oral therapy 1
- Diabetic foot infections: 14-28 days 2
- VRE infections: 7-28 days 2
Special Populations and Dosing Considerations
In patients with augmented renal clearance (CrCL ≥ 60 mL/min/1.73 m²), consider dose escalation to 450 mg every 8 hours for optimal efficacy. 3 However, escalation to 600 mg every 8 hours should not be recommended due to unacceptably high risk of thrombocytopenia. 3
For patients with coagulase-negative staphylococcal infections and reduced renal function (CrCL < 130 mL/min/1.73 m²), dose reduction to 450 mg every 12 hours may be optimal. 3
Critical Monitoring Requirements
Complete blood counts must be monitored weekly in all patients receiving linezolid, particularly those treated for longer than 2 weeks, as myelosuppression risk increases significantly with prolonged administration. 1
Additional monitoring for extended treatment includes:
- Visual acuity and color discrimination testing monthly for patients on extended therapy 1
- Consider prophylactic pyridoxine in patients at risk for peripheral neuropathy (diabetes, alcohol abuse, malnutrition) 1
Important Drug Interactions and Contraindications
Avoid concomitant use with monoamine oxidase inhibitors or within 2 weeks of taking such medications. 1 Linezolid has weak MAOI properties and can cause serotonin toxicity when combined with serotonergic drugs. 4
Avoid linezolid in patients with:
- Uncontrolled hypertension 1
- Pheochromocytoma 1
- Carcinoid tumor 1
- Thyrotoxicosis 1
- Bipolar depression, schizophrenia, or acute confusional states 1
For patients on serotonergic drugs (SSRIs, SNRIs), consider tapering or reducing the dosage of these medications during linezolid therapy to prevent serotonin toxicity. 4
Clinical Efficacy Data
The FDA label demonstrates strong efficacy with the standard 600 mg every 12 hours regimen:
- MRSA skin infections: 79% cure rate 2
- Diabetic foot infections: 83% cure rate in clinically evaluable patients 2
- VRE infections: 67% cure rate in intent-to-treat population 2
- Pediatric Gram-positive infections: 91% cure rate in clinically evaluable patients 2
Common Pitfalls to Avoid
Never use linezolid empirically for catheter-related bloodstream infections—vancomycin or daptomycin are preferred first-line agents. 1
Patients with CrCL ≥ 130 mL/min/1.73 m² or those on P-glycoprotein modulators require therapeutic drug monitoring to optimize dosing, as standard doses may be inadequate. 3
The most common adverse events include gastrointestinal disturbances (9.8%), thrombocytopenia (7.4%), decreased hemoglobin/hematocrit (4.1%), and cutaneous reactions (4.0%). 5