Clinical beta

FMBM is currently in clinical beta. Content is for professional review/testing and must not replace local protocols, senior clinical judgment, or official prescribing references.

Drug Monograph

Linezolid

Linezolid

Oxazolidinone (IV, PO)

MRSAVREMAOI-likePO bioavailable

Indication

MRSA pneumonia β€’ SSTI β€’ VRE β€’ meningitis adjunct selected β€’ TB MDR sometimes

At a glance

INDICATIONS (CORE USE)

MRSA / VRE infection with **100% PO bioavailability**; **serotonin syndrome** risk; **myelosuppression** with prolonged use; **peripheral neuropathy** long course.

ADULT DOSE (STANDARD)

600 mg IV/PO q12h (most serious); 400 mg q12h some indications β€” verify label

MAX DOSE

600 mg q12h typical adult max for infection

Route

IV, PO

PEDIATRIC DOSE

Pediatric mg/kg q8–12h per reference

Do not miss

Must-not-miss safety points

Major warning

- **Serotonin syndrome** with SSRIs, SNRIs, triptans, MAOIs β€” avoid or hold serotonergics - **Myelosuppression** β€” CBC weekly if >2 weeks therapy - **Lactic acidosis** β€” rare but reported; hold if unexplained acidosis - Not first-line for catheter-related bacteremia without source control

Indications

USE IF: MRSA / VRE when oral step-down equals IV; pneumonia/SSTI per susceptibility. AVOID IF: Concurrent serotonergic meds when avoidable; uncomplicated infection treatable narrower/safer.

Primary

  • MRSA pneumonia (including HAP/VAP when susceptible and course appropriate)
  • Complicated SSTI due to MRSA
  • Vancomycin-resistant enterococcal infection (VRE) when susceptible

Secondary

  • Meningitis adjunct in MDR gram-positive protocols (specialist)
  • MDR-TB oral component in some regimens

Other

  • Oral step-down from vancomycin when clinically stable

Dosing

STANDARD (ADULT PO)

600 mg PO/IV q12h

ADULT DOSE

600 mg q12h; no renal adjustment (unique among many antibiotics)

PEDIATRIC DOSE

Weight-based dosing β€” consult.

MAX DOSE

600 mg q12h (usual adult)

Practical Note

IV to PO 1:1 mg conversion.

Warnings

Clinical warnings

  • Optic neuropathy with >28 days (rare)
  • Peripheral neuropathy prolonged

Adverse effects

  • thrombocytopenia
  • nausea
  • diarrhea
  • headache

Contraindications

  • Hypersensitivity to linezolid

Drug interactions

  • SSRIs/SNRIs β€” serotonin syndrome
  • Adrenergic agents β€” pressor sensitivity (MAOI-like)
  • Rifampin β€” ↓ linezolid exposure

Special populations

Pediatrics

Pediatric mg/kg q8–12h per reference

Pregnancy

Animal data caution β€” human use if benefit

Lactation

excretion unknown degree β€” caution.

Renal impairment

No dose reduction for renal failure (metabolized); watch drug interactions more. **CrCl scaffold (FMBM β€” titrate to FDA/SFDA label + institutional pharmacy nomogram):** - **CrCl β‰₯50** β†’ **no routine dose reduction** (non-renal clearance dominant) - **CrCl 10–50** β†’ usually no CrCl-based change β€” toxicity surveillance - **CrCl <10** β†’ still typically standard dose; **severe renal + hepatic** impairment β†’ manufacturer guidance

Hepatic impairment

Severe hepatic impairment β€” manufacturer guidance; clinical monitoring.

Elderly

Polypharmacy β†’ serotonin risk; fall risk.

Administration

IV infusion ~30–60 min; PO with or without food.

Monitoring

  • Monitor: - Therapy **>2 weeks** β†’ **CBC weekly** β†’ falling platelets β†’ hold / ID review - SSRIs / SNRIs / triptans co-use β†’ altered mental status or autonomic surge β†’ evaluate **serotonin syndrome** - Visual symptoms with prolonged use β†’ **ophthalmology** referral - CBC weekly if therapy >2 weeks - Mental status if on SSRIs - Visual symptoms β†’ urgent ophtho if prolonged therapy
  • Recheck: - No clinical improvement at 48–72h β†’ reassess diagnosis, resistance, source control, and drug interactions - If targets not met after reassessment of dose, organ function, and interactions β†’ escalate per protocol (DO NOT continue blindly)

Overdose / toxicity

Clinical Picture

**Life-threatening (first):** **serotonin syndrome** (hyperthermia, autonomic storm); **severe pancytopenia**. **Secondary:** prolonged myelosuppression; lactic acidosis (rare).

Immediate Actions

Stop linezolid if serotonin tox β†’ cooling, benzos; cyproheptadine per toxicology if severe

Antidote

No specific antidote; serotonin syndrome β†’ cyproheptadine per toxicology if indicated; treat complications (e.g. anaphylaxis β†’ epinephrine)

Decontamination

N/A

Escalation

Hyperthermia, rigidity, multi-organ failure β†’ **ICU**

Clinical pearls

Common mistakes, resistance logic, and bedside traps

High-Yield Summary

Oral = IV for many MRSA/VRE scenarios. **Drug interaction monster** (serotonin + pseudo-MAOI). **Platelets** on long course.

Clinical pearls

Stewardship: reserve prolonged courses. De-escalation off linezolid when cultures negative and narrow option exists. TB: only in MDR programs. *Stewardship (all antimicrobials):* Empiric choice β†’ syndrome severity + **local antibiogram**; shortest effective course.

Stewardship & safety

  • Med reconciliation SSRIs
  • CBC long course
  • Lactic acidosis rare

Pharmacokinetics

100% oral bioavailability; hepatic metabolism; penetrates lung well.

Mechanism of action

Binds 50S ribosome β€” inhibits protein synthesis; bacteriostatic for many organisms.

Common brand names

Saudi Arabia

Zyvox, Linezolid

Global

(placeholder β€” verify local formulary)

Common trade names are curated examples only β€” formulations and availability vary. Verify the exact product name with your local pharmacy and national regulator before prescribing or dispensing.

Country practice notes

  • Empiric choice β†’ tie to syndrome, severity, and local antibiogram β€” not habit.
  • IV β†’ PO step-down when oral bioavailability and susceptibility allow.
  • Do not use antibiotics for uncomplicated viral illness β€” stewardship.

References

Saudi Arabia

  • SFDA (Saudi Food & Drug Authority)
  • Saudi National Formulary / MOH (where available)

International

  • WHO Model List of Essential Medicines (verify current edition)
  • US FDA or EU EMA product information (when national SmPC is unavailable)
  • Sanford Guide
  • IDSA / ESCMID (indication-specific)
  • Local antimicrobial stewardship / hospital formulary
  • FDA / SFDA / regional product labeling
  • Sanford Guide
  • IDSA / ESCMID (indication-specific)
  • Local antimicrobial stewardship / hospital formulary
  • FDA / SFDA / regional product labeling

Do not miss

  • Uncomplicated viral URI/bronchitis β†’ antibiotics rarely indicated
  • Narrow or stop when susceptibilities + clinical stability allow
  • Serotonin syndrome in patient on antidepressant.
  • VRE bacteremia needs source + ID β€” not just pills.
  • Med reconciliation SSRIs
  • CBC long course
  • Lactic acidosis rare