Usage
Dextrose + Linezolid is prescribed for the treatment of certain serious bacterial infections, specifically those caused by susceptible Gram-positive bacteria. These infections can include nosocomial pneumonia, community-acquired pneumonia, complicated skin and skin structure infections (cSSTIs), and vancomycin-resistant enterococcal infections. It is an antibiotic belonging to the oxazolidinone class.
Linezolid exerts its antibacterial effect by inhibiting bacterial protein synthesis. It binds to the 23S ribosomal RNA of the bacterial 50S subunit, preventing the formation of the 70S initiation complex, which is essential for bacterial protein synthesis.
Alternate Names
Linezolid is the generic name. A common brand name is Zyvox. The combination with dextrose is typically referred to as “Linezolid in 5% Dextrose.”
How It Works
Pharmacodynamics: Linezolid inhibits bacterial protein synthesis by binding to the 50S ribosomal subunit, preventing the formation of the 70S initiation complex. This bacteriostatic action is effective against a range of Gram-positive bacteria.
Pharmacokinetics:
- Absorption: Linezolid, when administered intravenously, is 100% bioavailable.
- Distribution: It distributes widely into tissues, achieving therapeutic concentrations in various organs.
- Metabolism: Primarily metabolized by oxidation, forming two inactive metabolites.
- Elimination: Primarily eliminated renally, with approximately 30% of the dose excreted unchanged in urine. The remaining is excreted as metabolites.
Mode of Action: Linezolid’s mechanism of action involves binding to a specific site on the bacterial 23S rRNA of the 50S subunit. This binding interferes with the formation of the 70S initiation complex, which is essential for the initiation of protein synthesis in bacteria.
Receptor Binding/Enzyme Inhibition: Linezolid is a reversible, non-selective inhibitor of monoamine oxidase (MAO).
Dosage
Standard Dosage
Adults: 600 mg every 12 hours, administered intravenously over 30-120 minutes. The maximum treatment duration is generally 28 days.
Children (≥12 years): 600 mg every 12 hours, administered intravenously over 30-120 minutes. The maximum treatment duration is generally 28 days.
Children (<12 years): 10 mg/kg every 8 hours, administered intravenously over 30-120 minutes for 10-14 days (or 14-28 days for nosocomial pneumonia).
Special Cases:
- Elderly Patients: No dosage adjustment is typically required.
- Patients with Renal Impairment: No dosage adjustment is required, but caution is advised in patients with severe renal impairment (CrCl < 30 mL/min).
- Patients with Hepatic Dysfunction: No dosage adjustment is required.
- Patients with Comorbid Conditions: Monitor closely for potential drug interactions, especially in patients with diabetes, hypertension, hyperthyroidism, pheochromocytoma, and carcinoid syndrome. Closely monitor blood glucose levels in patients with diabetes.
Clinical Use Cases
Dosage for these clinical scenarios follows the standard adult and pediatric dosing guidelines:
- Intubation
- Surgical Procedures (prophylactic use not recommended)
- Mechanical Ventilation
- Intensive Care Unit (ICU) Use
- Emergency Situations
Dosage Adjustments
Dose adjustments may be needed based on clinical response, adverse events, and drug interactions. Consult specific guidelines and monitor patients closely.
Side Effects
Common Side Effects
Diarrhea, headache, nausea, vomiting, dizziness, rash, taste alteration.
Rare but Serious Side Effects
Myelosuppression (thrombocytopenia, anemia, leukopenia), serotonin syndrome, lactic acidosis, peripheral neuropathy, optic neuropathy (including vision loss), seizures, Clostridium difficile-associated diarrhea, hypertensive crisis (especially with tyramine-containing foods or interacting medications).
Long-Term Effects
Peripheral neuropathy, optic neuropathy, vision changes, and myelosuppression.
Adverse Drug Reactions (ADR)
Serotonin syndrome, hypertensive crisis, severe myelosuppression, lactic acidosis, angioedema, anaphylaxis.
Contraindications
Hypersensitivity to linezolid, concurrent use of MAO inhibitors, untreated pheochromocytoma, concurrent use of serotonergic drugs (unless essential).
Drug Interactions
Serotonergic drugs (SSRIs, SNRIs, TCAs, MAOIs), adrenergic drugs (pseudoephedrine, phenylephrine), tyramine-containing foods, myelosuppressive agents.
Pregnancy and Breastfeeding
Pregnancy Category C. Linezolid should be used during pregnancy only if clearly needed.
Linezolid is excreted in breast milk. Breastfeeding is generally not recommended during linezolid therapy.
Drug Profile Summary
- Mechanism of Action: Inhibits bacterial protein synthesis by binding to the 50S ribosomal subunit.
- Side Effects: Diarrhea, headache, nausea, vomiting, myelosuppression, serotonin syndrome, peripheral/optic neuropathy.
- Contraindications: Hypersensitivity, concurrent MAOI use.
- Drug Interactions: Serotonergic drugs, adrenergic drugs, tyramine-containing foods.
- Pregnancy & Breastfeeding: Use with caution if benefits outweigh risks. Breastfeeding not recommended.
- Dosage: Adults/Children (≥12 years): 600 mg q12h IV. Children (<12 years): 10 mg/kg q8h IV.
- Monitoring Parameters: CBC, blood pressure, blood glucose, visual function, signs of serotonin syndrome.
Popular Combinations
Linezolid is generally used as a single agent. Combination therapy may be considered in cases of mixed infections or documented resistance, but careful consideration of drug interactions is crucial.
Precautions
Obtain complete medical history, monitor for myelosuppression, serotonin syndrome, and drug interactions. Avoid tyramine-rich foods. Monitor blood pressure and glucose levels. Evaluate for C. difficile infection in cases of diarrhea. Perform baseline and periodic ophthalmologic evaluations, especially with prolonged use.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Dextrose + Linezolid?
A: Adults and children ≥12 years: 600 mg every 12 hours IV. Children <12 years: 10 mg/kg every 8 hours IV.
Q2: How is Linezolid administered?
A: It is administered intravenously over 30-120 minutes.
Q3: What are the most common side effects of Linezolid?
A: Diarrhea, headache, nausea, and vomiting.
Q4: What is the maximum recommended duration of therapy for Linezolid?
A: Generally, 28 days.
Q5: Can Linezolid be used in pregnant women?
A: It should be used only if the potential benefit justifies the potential risk to the fetus.
Q6: What is the mechanism of action of Linezolid?
A: It inhibits bacterial protein synthesis by binding to the 50S ribosomal subunit.
Q7: Does Linezolid interact with other medications?
A: Yes. It interacts significantly with serotonergic drugs, adrenergic drugs, and tyramine-containing foods.
Q8: What should be monitored in patients receiving Linezolid?
A: Complete blood count (CBC), blood pressure, liver function tests, blood glucose levels, and signs and symptoms of serotonin syndrome.
Q9: Can Linezolid be used to treat viral infections?
A: No. Linezolid is specifically effective against certain Gram-positive bacteria. It is not effective against viral infections.
Q10: What should a patient do if they miss a dose of Linezolid?
A: They should take the missed dose as soon as they remember. However, if it is almost time for the next dose, they should skip the missed dose and take the next scheduled dose. They should not double the dose to catch up.
