Linezolid is a synthetic oxazolidinone antibacterial agent, available in three dosage forms: intravenous injection, tablets, and oral suspension.
How to Use Linezolid
Intravenous Injection
It is a ready-to-use sterile isotonic solution containing 2 mg of linezolid per milliliter, which can be directly used for intravenous infusion.
No dosage adjustment is required for intravenous administration, and the infusion time should be controlled between 30 and 120 minutes.
Tablets
Available in two specifications: 400 mg and 600 mg, as film-coated compressed tablets.
The absolute bioavailability of oral administration is close to 100%, and oral and intravenous administrations can be switched without dosage adjustment.
Tablets can be taken with food or on an empty stomach; however, a high-fat diet may delay the time to reach peak concentration and reduce the peak concentration by approximately 17%.
Oral Suspension
It is an orange-flavored granule/powder. After reconstitution, each 5 mL of the suspension contains 100 mg of linezolid.
A special reminder for patients with phenylketonuria: each 5 mL of the suspension contains 20 mg of phenylalanine, while other dosage forms do not contain this component.
Dosage Adjustment of Linezolid
Standard Dosage for Adults
The recommended dosage is 600 mg every 12 hours (administered intravenously or orally). The duration of treatment depends on the type and severity of the infection, but the maximum treatment course evaluated in clinical controlled trials is 28 days.
Patients with Renal Impairment
Linezolid and its two main metabolites may accumulate in patients with renal impairment, and the degree of accumulation increases with the severity of renal damage.
Although the pharmacokinetics of linezolid itself do not change in patients with renal impairment, clinicians should still weigh the potential risks of metabolite accumulation in clinical practice.
Hemodialysis can remove approximately 30% of the dosage; it is recommended to administer the drug after hemodialysis.
Patients with Hepatic Impairment
No dosage adjustment is required for patients with mild to moderate hepatic impairment (Child-Pugh Class A or B).
Currently, there are no pharmacokinetic data available for patients with severe hepatic impairment.
Pediatric Patients
Currently, complete pharmacokinetic data on multiple administrations in pediatric patients of all age groups are lacking, and there is no medication data for infants under 3 months of age.
When pediatric patients receive 10 mg/kg of linezolid via intravenous administration, the clearance rate corrected by body weight is higher than that in adults, and the apparent elimination half-life is shorter than that in adults.
Medication Use in Special Populations for Linezolid
Elderly Patients
There are no significant changes in the pharmacokinetic parameters of elderly patients (aged 65 years and above), so no dosage adjustment is required.
In clinical studies, 29% of patients were aged ≥ 65 years, and 12% were aged ≥ 75 years; no overall difference in efficacy was observed compared with younger patients.
Pregnant Women
Classified as Pregnancy Category C.
Animal studies have shown that embryonic and fetal toxicity may occur when the exposure level is equal to or higher than the expected level in humans.
Linezolid should be used during pregnancy only when the potential benefit outweighs the potential risk to the fetus.
Lactating Women
Linezolid and its metabolites can be excreted in breast milk, with concentrations similar to those in maternal plasma.
Given that many drugs can be excreted in human milk, lactating women should use linezolid with caution.
