Minimally metabolized; possibly by CYP isoenzymes.
Does not inhibit CYP1A2, 2C9, 2C19, 2D6, 2E1, or 3A4. Does not induce CYP isoenzymes.
Drugs Affecting or Metabolized by Hepatic Microsomal Enzymes
Potent inducers of hepatic enzymes: Possible reduced linezolid concentrations.
Specific Drugs
Drug
Interaction
Comments
Aminoglycosides
Gentamicin: No effect on pharmacokinetics of linezolid or gentamicin  
Gentamicin or streptomycin: In vitro evidence of additive or indifferent antibacterial effects
Ampicillin
In vitro evidence of additive or indifferent antibacterial effects
Antidiabetic agents, oral
Potential for hypoglycemia
Dosage reduction of antidiabetic agent or discontinuance of linezolid or antidiabetic agent may be necessary
Aztreonam
No effect on pharmacokinetics of either drug  
In vitro evidence of additive or indifferent antibacterial effects
Carbamazepine
Possible decreased linezolid concentrations
Carbapenems
Imipenem: In vitro evidence of additive or indifferent antibacterial effects
Insulin
Potential for hypoglycemia
Dosage reduction of insulin or discontinuance of linezolid or insulin may be necessary
MAO inhibitors (isocarboxazid, phenelzine, selegiline, tranylcypromine)
Potential pharmacologic interaction
Increased risk of CNS toxicity, including serotonin syndrome 
Do not use linezolid in patients who are receiving (or have received within the last 2 weeks) an MAO inhibitor (see Serotonergic Drugs under Specific Drugs)
Phenobarbital
Possible decreased linezolid concentrations
Phenytoin
Effect on phenytoin pharmacokinetics unlikely; possible decreased linezolid concentrations
Dosage adjustments not needed
Rifampin
Decreased peak plasma concentration and AUC of linezolid
In vitro evidence of additive or indifferent antibacterial effects
Mechanism of the interaction and clinical importance unknown
Serotonergic drugs (SSRIs, SNRIs, tricyclic antidepressants, amoxapine, bupropion, buspirone, maprotiline, meperidine, mirtazapine, nefazodone, trazodone, vilazodone)
Increased risk of serotonin syndrome, particularly with SSRIs and SNRIs;         unclear whether risk associated with other serotonergic drugs is comparable to that reported with SSRIs and SNRIs
Do not use concurrently unless considered clinically appropriate and patient can be carefully monitored for manifestations of serotonin syndrome or NMS-like reactions 
If urgent linezolid treatment necessary (e.g., life-threatening infections caused by MRSA or vancomycin-resistant E. faecium), promptly discontinue the serotonergic antidepressant and administer linezolid with close monitoring (see Serotonin Syndrome under Cautions)
Serotonergic drug may be initiated or resumed 24 hours after last linezolid dose
Sympathomimetic agents
Reversible enhancement of pressor response may occur if linezolid used concomitantly with indirect-acting sympathomimetic agents (e.g., phenylpropanolamine, pseudoephedrine), vasopressor agents (e.g., epinephrine, norepinephrine), or dopaminergic agents (e.g., dopamine, dobutamine)
Do not use concomitantly unless patient monitored for potential BP increases
If adrenergic agent (e.g., dopamine, epinephrine) initiated in patient receiving linezolid, use lower initial doses of the adrenergic agent and titrate dosage to achieve desired response
Vancomycin
In vitro evidence of additive or indifferent antibacterial effects
Vitamins (ascorbic acid, vitamin E)
Ascorbic acid or vitamin E: Concomitant use slightly increases linezolid AUC
Ascorbic acid or vitamin E: Dosage adjustments not needed
Warfarin
No substantial effect on warfarin pharmacokinetics
Dosage adjustments not needed
 Linezolid drug interactions (more detail)
