What are the contraindications for linezolid (oxazolidinone antibiotic)?

Contraindications for Linezolid

Linezolid is absolutely contraindicated in patients with hypersensitivity to the drug, those taking MAO inhibitors (or within 2 weeks of discontinuation), patients on serotonergic agents, and those with uncontrolled hypertension, pheochromocytoma, thyrotoxicosis, carcinoid syndrome, bipolar depression, schizophrenia, or acute confusional states. 1, 2

Absolute Contraindications

Hypersensitivity

• Known hypersensitivity to linezolid or any product components 1, 2

Monoamine Oxidase Inhibitor Interactions

• Concurrent use with MAO inhibitors A or B (e.g., phenelzine, isocarboxazid, selegiline, moclobemide) 1, 2
• Use within 2 weeks of discontinuing any MAO inhibitor 1, 2
• This contraindication exists because linezolid itself is a weak, reversible MAO inhibitor, creating risk of severe CNS reactions 3, 4

Serotonergic Drug Interactions

• Concurrent use with serotonin reuptake inhibitors (SSRIs) 1, 3
• Tricyclic antidepressants 1
• Serotonin 5-HT1 receptor agonists (triptans) 1
• Meperidine 1
• Buspirone 1
• These combinations risk potentially fatal serotonin syndrome 3, 5

Cardiovascular and Endocrine Conditions

• Uncontrolled hypertension 1, 2, 3
• Pheochromocytoma 1, 2, 3
• Thyrotoxicosis 1, 2, 3
• Carcinoid syndrome 1, 2

Psychiatric Conditions

• Bipolar depression 2
• Schizophrenia 2
• Acute confusional states 2

Sympathomimetic and Vasopressor Interactions

Unless blood pressure is carefully monitored, linezolid should not be used with:

• Directly and indirectly acting sympathomimetic agents (e.g., pseudoephedrine) 1
• Vasopressive agents (e.g., epinephrine, norepinephrine) 1
• Dopaminergic agents (e.g., dopamine, dobutamine) 1

Breastfeeding

• Breastfeeding is contraindicated during linezolid therapy 2

Important Cautions (Not Absolute Contraindications)

Pregnancy

• Use with caution in pregnancy; not an absolute contraindication but requires careful risk-benefit assessment 2

Dietary Restrictions

• Avoid consumption of large amounts of tyramine-rich foods due to MAO inhibitor properties 2, 6

Pre-existing Conditions Requiring Enhanced Monitoring

• Epilepsy or history of seizures (increased risk of convulsions) 2
• Pre-existing anemia (significantly higher risk of severe linezolid-induced anemia) 7, 8
• Renal impairment (metabolites may accumulate, though no dose adjustment required) 2
• Liver disease (use with caution and monitor closely) 2

Critical Clinical Pitfall

The most commonly overlooked contraindication in general medical practice is the interaction with SSRIs and other serotonergic agents, as linezolid functions as an MAOI "in disguise" 5. Medical and surgical practitioners unfamiliar with MAOI pharmacology may inadvertently precipitate hypertensive crisis or serotonin syndrome when prescribing linezolid to patients on antidepressants 5.