Linezolid
ZYVOX
Pronunciation: li-NE-zoe-lid
“Line is solid”
What it isOxazolidinone inhibiting the bacterial 50S subunit; MRSA and vancomycin-resistant Enterococcus infections.
Why this oneComplete oral absorption lets tablets replace IV therapy without loss of exposure, and lung penetration is strong.
What limits it⚑ It reversibly inhibits MAO, creating serotonin-syndrome risk with serotonergic drugs. Myelosuppression and optic or peripheral neuropathy emerge with prolonged use.
Pearls
- As effective as vancomycin for serious MRSA despite being bacteriostatic.
- Suppresses bacterial toxin production.
- Thrombocytopenia mainly after 10 days; check CBC weekly.
Linezolid prescription history
Animated chart of estimated U.S. prescriptions per year, Antibacterials (systemic) (1938–2026). Linezolid enters in 2000 (estimated).
FDA-approved for
- resistant gram-positive infections (2000)
Principal riskA reversible MAOI: serotonin syndrome with SSRIs
Classes and tags
Clinical profile
Legacy pregnancy categoryC
Defining liabilityAllergy, gastrointestinal effects and agent-specific renal, hepatic, hematologic or interaction risks.
FDA label
Read the full label on DailyMed ↗
NO BOXED WARNINGS
| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| Nosocomial/community-acquired pneumonia, complicated SSSI, VRE infections | Adults & adolescents >=12 yr | 600 mg PO q12h | 600 mg q12h | 600 mg q12h |
| Uncomplicated SSSI | Adults | 400 mg PO q12h | 400 mg q12h | 400 mg q12h |
| Uncomplicated SSSI | Adolescents >=12 yr | 600 mg PO q12h | 600 mg q12h | 600 mg q12h |
| Pneumonia, complicated SSSI, VRE infections | Pediatric birth–11 yr | 10 mg/kg PO q8h | 10 mg/kg q8h | |
| Uncomplicated SSSI | Pediatric <5 yr / 5–11 yr | <5 yr: 10 mg/kg q8h; 5–11 yr: 10 mg/kg q12h |
Renal Undefined
Hepatic Undefined
Preterm neonates <7 days old: start 10 mg/kg q12h, increase to q8h by day 7 of life.
Instructions
- No dose adjustment when switching from IV to oral.
- Duration by indication: pneumonia/complicated & uncomplicated SSSI 10–14 days; VRE infections 14–28 days.
- Monitor complete blood counts weekly, especially with therapy >2 weeks.
- Observe MAOI/serotonergic/sympathomimetic and tyramine-food precautions (reversible nonselective MAO inhibitor).
Available strengths
- tab 600 mg
- susp 100 mg/5 mL
- inj 2 mg/mL
Contraindications
- Concurrent use with, or within 2 weeks of, any MAO inhibitor (e.g., phenelzine, isocarboxazid)
Cautions
- Myelosuppression (anemia, leukopenia, thrombocytopenia, pancytopenia) — worse in severe renal or moderate-severe hepatic impairment
- Peripheral and optic neuropathy, primarily with therapy >28 days
- Serotonin syndrome with concomitant serotonergic agents
- Lactic acidosis; convulsions
- Hypoglycemia in diabetics on insulin/oral agents
- Hyponatremia and/or SIADH
- Blood-pressure elevation with sympathomimetics, tyramine-rich foods, uncontrolled hypertension, pheochromocytoma, thyrotoxicosis
- C. difficile-associated diarrhea; mortality imbalance in catheter-related bloodstream infections (not an approved use)
Adverse reactions
- Diarrhea
- Nausea, vomiting
- Headache
- Anemia, thrombocytopenia
- Taste alteration
Pregnancy Available data have not identified a drug-associated risk of major birth defects or miscarriage; animal embryo-fetal toxicity/lethality at maternally toxic doses.
Lactation Present in breast milk (~6–9% of the infant therapeutic dose); monitor breastfed infant for diarrhea and vomiting.
Cost
| Strength | #/mo | generic $ | CostPlus | |
|---|---|---|---|---|
| 600 mg | tab | 60 BID | $86.47/mo | offered |
| 100 mg/5 mL | susp | per unit | $2.74/mL | not offered |
| 2 mg/mL | inj | per unit | not offered |
Generic entryBy 2023
Serotonin and MAOI
Provisional washout figures
Elevating mechanismMAO-A inhibitor
Non-elevating actionNone recorded
Exposure dependenceTherapeutic exposure
Washout AFTER an MAOI1 days
Evidence confidenceHigh
InterpretationClinically meaningful reversible MAO-A inhibition; significant SRI combinations can produce severe toxicity.
Open Linezolid in the interactive console ↗
Self-check
- Why can oral linezolid replace IV therapy without loss of exposure?
Complete oral absorption. - What linezolid mechanism creates serotonin-syndrome risk?
Reversible MAO inhibition.