Oxazolidinone — MRSA / VRE / Drug-Resistant TB (adjunct) Pregnancy: eMC §4.6: limited data in pregnant women; animal studies have shown reproductive toxicity and a potential risk for humans exists — should not be used during pregnancy unless clearly necessary (only if potential benefit outweighs theoretical risk). Breast-feeding should be discontinued prior to and throughout administration. Animal studies showed reduced fertility.

Linezolid

Brand names: Zyvox

Linezolid is an oxazolidinone antibacterial used for resistant Gram-positive infections, including MRSA and vancomycin-resistant enterococci.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: 600 mg

Route: Oral (film-coated tablets; SPC notes oral bioavailability approx. 100%, so no dose adjustment when switching from the parenteral formulation)

Frequency: Twice daily

Max: 600 mg twice daily is the recommended dose; maximum treatment duration 28 days (safety and effectiveness beyond 28 days not established)

eMC §4.2 durations: nosocomial pneumonia and community-acquired pneumonia 600 mg twice daily for 10-14 consecutive days; complicated skin and soft tissue infections 600 mg twice daily. Duration depends on pathogen, site and severity of infection and clinical response. No increase in dose or duration is required for infections associated with concurrent bacteraemia. Tablets may be used as initial therapy and taken with or without food. Elderly: no dose adjustment. Hepatic impairment: no dose adjustment, but limited clinical data — use only where anticipated benefit outweighs theoretical risk. PAEDIATRIC: eMC states safety and efficacy in children under 18 years has not been established and no recommendation on a posology can be made; the US label carries a weight-based paediatric regimen not endorsed by the SPC — verify against a children's formulary before prescribing to under-18s. NOTE: comparator symbols (< / >) were lost in the source text extraction — verify all thresholds against the current SPC.

Dose adjustments

Renal

eMC §4.2: no dose adjustment required in renal impairment, including severe renal impairment (source text reads 'CLCR 30 ml/min' — comparator lost in extraction). Because of the unknown clinical significance of up to 10-fold higher exposure to the two primary metabolites in severe renal insufficiency, use with special caution and only when anticipated benefit outweighs theoretical risk. Approximately 30% of a dose is removed during 3 hours of haemodialysis — give linezolid after dialysis. No experience in CAPD or other renal replacement modalities.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

US labelling (FDA)

Reference — US labelling, may differ from UK

Dosage, Route, and Frequency of Administration Infection Pediatric Patients (Birth through 11 years of age) Adults and Adolescents (12 years and older) Duration (Days) Nosocomial pneumonia Community-acquired pneumonia, including concurrent bacteremia 10 mg/kg intravenous or oral every 8 hours 600 mg intravenous or oral every 12 hours 10 to 14 Complicated skin and skin structure infections Vancomycin-resistant Enterococcus faecium infections, including concurrent bacteremia 10 mg/kg intravenous or oral every 8 hours 600 mg intravenous or oral every 12 hours 14 to 28 Uncomplicated skin and skin structure infections less than 5 yrs: 10 mg/kg oral every 8 hours 5 to 11 yrs: 10 mg/kg oral every …

Source: US FDA prescribing information (openFDA / DailyMed), label dated 2025-01-30. Accessed 2026-06-12. US dosing and indications can differ from UK practice — use UK sources for prescribing decisions.

Contraindications

Hypersensitivity to linezolid or to any of the excipients
Patients taking any medicinal product that inhibits monoamine oxidase A or B (e.g. phenelzine, isocarboxazid, selegiline, moclobemide), or within two weeks of taking one
Unless facilities for close blood-pressure observation and monitoring are available: uncontrolled hypertension, phaeochromocytoma, carcinoid, thyrotoxicosis, bipolar depression, schizoaffective disorder, acute confusional states
Unless facilities for close blood-pressure observation and monitoring are available: concomitant serotonin re-uptake inhibitors, tricyclic antidepressants, 5-HT1 agonists (triptans), directly/indirectly acting sympathomimetics (including adrenergic bronchodilators, pseudoephedrine, phenylpropanolamine), vasopressive agents (e.g. epinephrine, norepinephrine), dopaminergic agents (e.g. dopamine, dobutamine), pethidine or buspirone
Breast-feeding should be discontinued prior to and throughout administration (animal data suggest passage into breast milk)

Side effects

Diarrhoea (8.9%), nausea (6.9%), vomiting (4.3%) — very common/common
Headache (4.2%), taste perversion (metallic taste), dizziness — common
Candidiasis (oral, vaginal), fungal infections — common
Thrombocytopenia, anaemia, and other myelosuppression (leucopenia, neutropenia, pancytopenia, sideroblastic anaemia) — uncommon to not known; monitor full blood count weekly
Peripheral and optic neuropathy, blurred vision, optic neuritis, loss of vision — rare/very rare, primarily with treatment longer than 28 days
Serotonin syndrome, convulsions, lactic acidosis, rhabdomyolysis, hyponatraemia, hypoglycaemia — rare/not known
Antibiotic-associated colitis including pseudomembranous colitis

Interactions

Monoamine oxidase inhibitors — linezolid is a reversible, non-selective MAO inhibitor; contraindicated concomitantly or within two weeks (eMC §4.3; openFDA §7.1)
Serotonergic agents (SSRIs, TCAs, triptans, pethidine, buspirone) — risk of serotonin syndrome; monitor (eMC §4.3; openFDA §5.3, §7.2)
Adrenergic/sympathomimetic and vasopressor agents (pseudoephedrine, phenylpropanolamine, epinephrine, norepinephrine, dopamine, dobutamine) — potential elevation of blood pressure; monitor (eMC §4.3; openFDA §5.6, §7.2)
Concomitant medicines that decrease haemoglobin, depress blood counts or affect platelet count/function — increased myelosuppression risk; monitor blood counts (eMC §4.4)
Insulin or oral hypoglycaemic agents in diabetes — postmarketing reports of symptomatic hypoglycaemia (openFDA §5)

Clinical monograph

How it works

It inhibits bacterial protein synthesis by binding the bacterial ribosome and preventing formation of the initiation complex.

Prescribing in practice

It is a weak monoamine oxidase inhibitor, so it can cause serotonin syndrome with SSRIs and other serotonergic drugs and interacts with tyramine-rich foods.
Reversible myelosuppression, especially thrombocytopenia, can occur with prolonged courses, so monitor the full blood count.
It has excellent oral bioavailability, allowing a switch from intravenous to oral therapy without loss of exposure.

Monitoring

Monitor the full blood count, particularly with treatment beyond about two weeks; review for peripheral and optic neuropathy if therapy is prolonged.

Counselling the patient

Avoid tyramine-rich foods such as mature cheese, and tell the team about any antidepressants before starting.
Report new visual changes, or numbness or tingling in the hands or feet, especially during longer courses.

Evidence & guidelines

An established option for resistant Gram-positive infection where oral therapy is valuable; use should follow local antimicrobial guidance.

Reference: MHRA Drug Safety Update 2014 (Linezolid Myelosuppression); WHO MDR-TB Treatment Guidelines 2022; IDSA MRSA Guidelines; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways