Zyvox (linezolid) is a synthetic antibacterial agent of the oxazolidinone class, specifically indicated for the treatment of certain severe infections caused by susceptible Gram-positive bacteria. It represents a critical therapeutic option, particularly for infections involving multidrug-resistant pathogens such as methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecium (VRE). Its unique mechanism of action and availability in both intravenous and oral formulations allow for flexible treatment strategies, including early switch therapy and outpatient parenteral antibiotic therapy (OPAT) protocols. This profile provides a comprehensive expert overview for healthcare professionals.

Features

• Active Ingredient: Linezolid.
• Pharmacologic Class: Oxazolidinone-class antibacterial.
• Available Formulations: 600 mg film-coated tablets; 100 mg/5 mL oral suspension; 2 mg/mL intravenous injection for infusion.
• Mechanism of Action: Binds to the 50S subunit of the bacterial ribosome, inhibiting the formation of the 70S initiation complex, a distinct mechanism that prevents cross-resistance with other protein synthesis inhibitors.
• Spectrum of Activity: Bacteriostatic against enterococci and staphylococci; bactericidal against most strains of streptococci.
• Bioavailability: Oral formulation demonstrates approximately 100% bioavailability, permitting seamless transition from IV to oral therapy without dose adjustment.

Benefits

• Provides a potent therapeutic option for complex infections where resistance to other antimicrobials, such as beta-lactams and glycopeptides, is confirmed or suspected.
• The 100% oral bioavailability facilitates early hospital discharge and continuation of effective therapy in an outpatient setting, improving patient quality of life and potentially reducing healthcare costs.
• Its unique mechanism of action minimizes the potential for cross-resistance with other antibiotic classes, making it a valuable agent in the antimicrobial arsenal.
• Demonstrated efficacy in the treatment of complicated skin and skin structure infections (cSSSI), nosocomial pneumonia, and vancomycin-resistant enterococcal (VRE) infections.
• Offers a reliable alternative for patients with confirmed beta-lactam allergies or intolerances.

Common use

Zyvox is approved for the treatment of adults and specific pediatric populations with the following infections caused by susceptible strains of designated Gram-positive microorganisms:

• Complicated skin and skin structure infections (cSSSI), including diabetic foot infections without concomitant osteomyelitis, caused by Staphylococcus aureus (methicillin-susceptible and -resistant strains), Streptococcus pyogenes, or Enterococcus faecalis (vancomycin-susceptible strains only).
• Nosocomial pneumonia caused by Staphylococcus aureus (methicillin-susceptible and -resistant strains) or Streptococcus pneumoniae.
• Community-acquired pneumonia caused by Streptococcus pneumoniae, including cases with concurrent bacteremia, or Staphylococcus aureus (methicillin-susceptible strains only).
• Vancomycin-resistant Enterococcus faecium (VRE) infections, including cases with concurrent bacteremia.

Its use should be guided by, or in consultation with, the results of culture and susceptibility testing to ensure appropriate targeting and to curb the development of resistance.

Dosage and direction

• Adults and Adolescents (12 years and older): The recommended dosage for all indications is 600 mg administered intravenously or orally every 12 hours.
• Duration of Therapy: The duration of treatment is based on the infection site and clinical response.
  • cSSSI: 10 to 14 days.
  • Nosocomial Pneumonia & Community-Acquired Pneumonia: 10 to 14 days.
  • VRE infections: 14 to 28 days.
• Pediatric Patients (birth to 11 years): Dosage is based on body weight and administered IV or orally every 8 hours. Consult full prescribing information for detailed pediatric dosing tables.
• Administration:
  • Tablets/Oral Suspension: Can be taken with or without food.
  • IV Infusion: Must be administered over a period of 30 to 120 minutes. The IV solution is incompatible with co-infusion with other drugs; the infusion line must be flushed before and after administration.
• Renal/Hepatic Impairment: No dose adjustment is recommended for patients with renal impairment or mild-to-moderate hepatic impairment. Dose adjustment in severe hepatic impairment has not been thoroughly studied.

Precautions

• Myelosuppression: Zyvox has been associated with reversible myelosuppression (including anemia, leukopenia, pancytopenia, and thrombocytopenia). Complete blood counts (CBC) should be monitored weekly, especially in patients receiving therapy for longer than 2 weeks, those with pre-existing myelosuppression, those receiving concomitant drugs that may cause bone marrow suppression, or those with chronic infections who have received previous or concomitant antibiotic therapy.
• Peripheral and Optic Neuropathy: Cases of peripheral and optic neuropathy have been reported, primarily in patients treated for extended periods (≥ 28 days). Patients should be monitored for visual function and questioned about visual changes. If symptoms of neuropathy occur, continued use warrants weighing the potential risks against the benefits.
• Serotonin Syndrome: Spontaneous reports of serotonin syndrome have been reported in patients receiving Zyvox concomitantly with serotonergic agents, including SSRIs, SNRIs, and TCAs. Patients should be closely monitored for signs of autonomic hyperactivity, neuromuscular excitability, and mental status changes.
• Lactic Acidosis: Cases of lactic acidosis have been reported. Patients who develop recurrent nausea, vomiting, or unexplained acidosis should receive immediate medical evaluation.
• Convulsions: Seizures have been reported in patients treated with Zyvox. Caution is advised in patients with a history of seizures.
• Clostridioides difficile-Associated Diarrhea (CDAD): CDAD has been reported with nearly all antibacterial agents and may range in severity from mild diarrhea to fatal colitis. Evaluate if diarrhea occurs during or after therapy.

Contraindications

Zyvox is contraindicated in the following patient populations:

• Patients with known hypersensitivity to linezolid or any other component of the product.
• Patients taking any monoamine oxidase inhibitors (MAOIs) (e.g., phenelzine, isocarboxazid) or within two weeks of taking such drugs.
• Patients with uncontrolled hypertension, pheochromocytoma, thyrotoxicosis, and/or those taking directly and indirectly acting sympathomimetic agents (e.g., pseudoephedrine), vasopressive agents (e.g., epinephrine, norepinephrine), or dopaminergic agents (e.g., dopamine, dobutamine) unless patients are closely monitored for changes in blood pressure.
• Patients with carcinoid syndrome and/or those taking serotonergic agents, unless patients are closely monitored for signs and symptoms of serotonin syndrome.

Possible side effect

The most common adverse reactions (≥5% of patients in clinical trials) include:

• Diarrhea
• Nausea
• Headache
• Vomiting
• Anemia Other important, though less common, side effects can include:
• Thrombocytopenia
• Leukopenia
• Tongue discoloration
• Oral candidiasis
• Vaginal candidiasis
• Fungal infection
• Insomnia
• Dizziness
• Localized abdominal pain
• Dyspepsia
• Loose stools
• Pruritus
• Rash
• Elevated liver enzymes (e.g., ALT, AST, LDH, alkaline phosphatase)
• Increased blood creatinine, BUN

Drug interaction

Zyvox has significant interactions due to its weak, reversible inhibition of monoamine oxidase (MAO):

• Adrenergic and Serotonergic Agents: Contraindicated or requires extreme caution with MAOIs, sympathomimetics (e.g., pseudoephedrine, phenylpropanolamine), vasopressors (e.g., epinephrine, norepinephrine), dopamine, dobutamine, and serotonergic psychiatric agents (SSRIs, SNRIs, TCAs, triptans, buspirone, meperidine). Can lead to potentiated pressor response or serotonin syndrome.
• Tyramine-Rich Foods: While a strict tyramine-free diet is not required, patients should be advised to avoid consuming large amounts of tyramine-rich foods (e.g., aged cheeses, fermented meats, draft beers, soy products, sauerkraut) as excessive tyramine intake may cause a pressor response.

Missed dose

If a dose is missed, it should be taken as soon as it is remembered. However, if it is almost time for the next scheduled dose, the missed dose should be skipped. The patient should not take a double dose to make up for the missed one. The regular dosing schedule should then be resumed.

Overdose

There is no specific antidote for Zyvox overdose. Reported cases of acute overdose have been limited and associated with adverse events similar to those reported with recommended dosing. Supportive care is advised, with maintenance of glomerular filtration. Hemodialysis may accelerate the removal of linezolid and its metabolites. Data from a limited number of patients suggest approximately 30% of a dose is eliminated during a 3-hour hemodialysis session.

Storage

• Tablets: Store at 20°C to 25°C (68°F to 77°F); excursions permitted between 15°C and 30°C (59°F and 86°F). Protect from light and moisture.
• Oral Suspension: Store constituted suspension at room temperature. Use within 21 days after reconstitution. Do not freeze. Keep bottle tightly closed.
• IV Injection: Store IV bags at room temperature. Protect from freezing. Protect from light. Zyvox IV is a single-use solution; any unused portion must be discarded.

Disclaimer

This information is intended for educational purposes for healthcare professionals and is not a substitute for professional medical advice, diagnosis, or treatment. The content is derived from the product’s full prescribing information but may not be exhaustive. Always consult the most current, official full prescribing information before initiating or modifying any treatment regimen. The prescriber is responsible for determining the appropriate dosage and treatment for an individual patient based on their clinical condition, susceptibility reports, and potential for drug interactions.

Reviews

• “As an Infectious Disease specialist, Zyvox remains a cornerstone for managing outpatient MRSA infections and VRE bacteremia. The ability to transition to oral therapy with no loss of efficacy is a significant advantage for patient compliance and hospital resource management.” – ID Physician, 15 years experience.
• “In our ICU, we rely on Zyvox for nosocomial pneumonia with confirmed MRSA. Its predictable pharmacokinetics and spectrum make it a reliable choice. We maintain a high index of suspicion for myelosuppression with prolonged courses and monitor CBCs diligently.” – Critical Care Pharmacist.
• “The potential for drug interactions, particularly with commonly used antidepressants, requires vigilant medication reconciliation. However, when used appropriately with necessary monitoring, it is an exceptionally effective agent for resistant Gram-positive organisms.” – Clinical Pharmacist, Antimicrobial Stewardship Team.
• “We have successfully used the oral suspension formulation in pediatric patients with complex resistant infections, allowing for completion of therapy at home. This has been a game-changer for family quality of life.” – Pediatric Infectious Disease Specialist.