What is the recommended dosage and treatment duration of Linezolid (oxazolidinone antibiotic) for bacterial infections?

Linezolid Dosing and Treatment Duration

Standard Dosing Regimen

For most bacterial infections in adults, linezolid should be administered at 600 mg IV or PO every 12 hours, with treatment duration ranging from 10-14 days for uncomplicated infections to 14-28 days for more severe infections. 1, 2

Adult Dosing by Indication

• Complicated skin and soft tissue infections (cSSTI): 600 mg IV or PO every 12 hours for 10-14 days 1, 2
• Nosocomial pneumonia: 600 mg IV or PO every 12 hours for 14-28 days 1, 2
• Community-acquired pneumonia: 600 mg IV or PO every 12 hours for 14-28 days 1, 2
• Vancomycin-resistant Enterococcus (VRE) infections: 600 mg IV or PO every 12 hours, with duration dependent on site of infection and clinical response (strong recommendation) 1, 2
• Uncomplicated skin infections: 400 mg PO every 12 hours for 10-14 days 2

Bone and Joint Infections

• MRSA osteomyelitis: 600 mg PO/IV twice daily for a minimum of 8 weeks, with consideration for additional 1-3 months of oral therapy 1, 3
• Septic arthritis: 600 mg PO/IV twice daily for 3-4 weeks 1, 3

Central Nervous System Infections

• Meningitis: 600 mg PO/IV twice daily for 2 weeks minimum 1, 3
• Brain abscess, subdural empyema, spinal epidural abscess: 600 mg PO/IV twice daily for 2-6 weeks depending on specific infection 1, 3

Pediatric Dosing

Children under 12 years should receive 10 mg/kg IV or PO every 8 hours (not to exceed 600 mg per dose), while adolescents 12 years and older follow adult dosing of 600 mg every 12 hours. 1, 3, 2

Special Neonatal Considerations

• Neonates <7 days of age (especially preterm with gestational age <34 weeks): Start with 10 mg/kg every 12 hours due to lower systemic clearance 2
• All neonates by 7 days of life: Advance to 10 mg/kg every 8 hours 2

Pediatric Dosing by Age and Indication

• Uncomplicated skin infections in children <5 years: 10 mg/kg PO every 8 hours 2
• Uncomplicated skin infections in children 5-11 years: 10 mg/kg PO every 12 hours 2
• All other infections in children <12 years: 10 mg/kg IV or PO every 8 hours (maximum 600 mg/dose) 1, 2

Critical Monitoring Requirements

Hematologic Monitoring

Complete blood counts should be monitored weekly in all patients receiving linezolid, particularly those on therapy longer than 2 weeks, as myelosuppression risk increases significantly with prolonged administration. 3

• Thrombocytopenia occurs more frequently with linezolid compared to other antibiotics 4
• Most hematologic adverse effects are reversible upon discontinuation 5, 4

Neurologic Monitoring

Patients receiving extended linezolid treatment require monthly visual acuity and color discrimination testing to detect optic neuropathy. 3

• Peripheral or optic neuropathy is associated with treatment durations of 3-6 months 4
• Consider prophylactic pyridoxine in patients at risk for peripheral neuropathy (diabetes, alcohol abuse, malnutrition) 3

Important Contraindications and Drug Interactions

Avoid linezolid in patients taking monoamine oxidase inhibitors or within 2 weeks of discontinuing such medications, and in patients with uncontrolled hypertension, pheochromocytoma, carcinoid tumor, thyrotoxicosis, bipolar depression, schizophrenia, or acute confusional states. 3

Administration Considerations

Route Flexibility

Linezolid has virtually complete oral bioavailability, allowing for 1:1 conversion between IV and oral formulations without dose adjustment. 2, 5

• Patients may be switched from IV to oral at the physician's discretion when clinically indicated 2
• IV administration should be infused over 30-120 minutes 2

Critical Dosing Error to Avoid

Never reduce linezolid dosing frequency to every 24 hours, as this fails to maintain adequate drug exposure for bactericidal activity. 3

Special Clinical Situations

Multidrug-Resistant Organisms

For VRE bacteremia, linezolid 600 mg IV or PO every 12 hours is strongly recommended, with treatment duration dependent on clinical response 1

• Clinical cure rates of 81.4% and microbiological cure rates of 86.4% have been demonstrated in VRE infections 1
• For VRE intra-abdominal infections, tigecycline may be preferred, but linezolid remains an option 1

Renal and Hepatic Impairment

No dose adjustment is necessary for mild to moderate renal or hepatic impairment. 5

Common Adverse Effects

The most frequently reported adverse effects include diarrhea, headache, and nausea 5, 6. Gastrointestinal disturbances occur in approximately 9.8% of patients, with thrombocytopenia in 7.4% and decreased hemoglobin/hematocrit in 4.1% 7.