Linezolid is a synthetic antibacterial agent of the oxazolidinone class, indicated for the treatment of infections caused by susceptible Gram-positive bacteria, including multidrug-resistant strains like methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecium (VRE). It is a critical reserve antibiotic in the Indian context, used primarily for complicated skin and soft tissue infections, hospital-acquired pneumonia, and specific resistant infections where other options have failed or are not suitable.
Adult: 600 mg orally or intravenously every 12 hours. Duration: Typically 10-14 days for pneumonia and 10-28 days for cSSSI, depending on infection severity and clinical response.
Note: Tablets can be taken with or without food. To minimize potential for tyramine interaction, advise patients to avoid large amounts of tyramine-rich foods. The IV formulation should be infused over 30-120 minutes. Oral and IV routes are interchangeable (1:1 bioavailability).
Linezolid inhibits bacterial protein synthesis by binding to the 50S ribosomal subunit. It binds to the A-site of the peptidyl transferase center (PTC), preventing the formation of the initiation complex. This action occurs at a very early stage of protein synthesis, distinct from other protein synthesis inhibitors like macrolides, lincosamides, and chloramphenicol.
Pregnancy: Category C: Animal studies have shown adverse effects (decreased fetal weight, increased post-implantation loss). There are no adequate and well-controlled studies in pregnant women. Use only if the potential benefit justifies the potential risk to the fetus.
Driving: May cause dizziness, vertigo, or visual disturbances (including optic neuropathy). Patients should be cautioned about operating machinery or driving until they know how linezolid affects them.
| Selective Serotonin Reuptake Inhibitors (SSRIs: e.g., Sertraline, Fluoxetine) | Increased risk of serotonin syndrome (confusion, hyperthermia, myoclonus, autonomic instability). | High |
| Serotonin-Norepinephrine Reuptake Inhibitors (SNRIs: e.g., Venlafaxine, Duloxetine) | Increased risk of serotonin syndrome. | High |
| Tricyclic Antidepressants (TCAs: e.g., Amitriptyline) | Increased risk of serotonin syndrome. | High |
| Monoamine Oxidase Inhibitors (MAOIs: e.g., Phenelzine) | Potentiation of MAOI effect, high risk of hypertensive crisis and serotonin syndrome. Contraindicated. | High |
| Sympathomimetics (e.g., Pseudoephedrine, Epinephrine) | Exaggerated pressor response leading to hypertensive crisis. | High |
| Dopaminergic Agents (e.g., Levodopa, Dopamine) | Potential for enhanced dopaminergic effects and hypertensive episodes. | Moderate |
| Tyramine-rich foods (Aged cheese, fermented meats, soy sauce, tap beer) | Risk of hypertensive crisis due to MAOI activity. | Moderate |
| Rifampin | May reduce linezolid plasma concentrations due to enzyme induction; monitor efficacy. | Moderate |