Pharmacology: Linezolid Overview

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary dosing recommendation for vancomycin in treating Staph aureus bacteremia?

10 mg/kg daily

6 mg/kg daily (correct)

4 mg/kg daily

8 mg/kg daily

Which side effect is associated with long-term use of linezolid?

Myelosuppression (correct)

Gastrointestinal bleeding

Nephrotoxicity

Hepatotoxicity

Which condition should be monitored for when administering linezolid with SSRIs?

Liver failure

Acute renal failure

Anaphylaxis

Serotonin syndrome (correct)

What is the mechanism of action for mupriricin?

Inhibits bacterial protein synthesis Signup and view all the answers

How should vancomycin therapy be monitored in terms of lab values?

Monitor CPK baseline and weekly Signup and view all the answers

What is a common use of mupirocin in clinical practice?

Eradicating MRSA colonization in nares Signup and view all the answers

What characteristic limitation does linezolid have regarding bacterial coverage?

Does not cover pneumonia Signup and view all the answers

What is the desired peak concentration for Vancomycin therapy?

20-40 mcg/ml Signup and view all the answers

Which of the following factors must be monitored during Vancomycin therapy?

Serum creatinine levels Signup and view all the answers

Which of these conditions is Vancomycin recommended for treating?

Beta-lactam resistant gram-positive infections Signup and view all the answers

Which side effect is commonly associated with Vancomycin and correlates with peak levels?

Nephrotoxicity Signup and view all the answers

What is the primary route of administration for Vancomycin in systemic infections?

Intravenous infusion Signup and view all the answers

What is the common dosing schedule for Vancomycin in most patients?

1-15 gm every 12 hours Signup and view all the answers

How should Vancomycin dosing be adjusted for patients with renal insufficiency?

Decrease dose frequency Signup and view all the answers

When should peak and trough levels for Vancomycin be monitored?

After the third dose Signup and view all the answers

What mechanism of action does Quinupristin/Dalfopristin utilize to inhibit bacterial growth?

Irreversibly binds to the 50s ribosomal subunit Signup and view all the answers

Which of the following is not a scenario in which Vancomycin should be avoided?

Treating MRSA infection Signup and view all the answers

What is the clinical significance of monitoring peaks and troughs for Vancomycin therapy?

To tailor dose adjustments and minimize toxicity Signup and view all the answers

For which condition has Quinupristin/Dalfopristin shown effectiveness?

Infections caused by VRE Signup and view all the answers

What should be done if cultures for a patient on Vancomycin therapy return negative?

Stop Vancomycin treatment Signup and view all the answers

What pharmacokinetic principle is essential for individualizing Vancomycin dosing?

Pharmacokinetic calculations for drug levels Signup and view all the answers

Vancomycin is the primary treatment for which of the following conditions?

MRSA infections Signup and view all the answers

Study Notes

Linezolid (Zyvox)

Unique antibiotic belonging to the oxazolidinone class.
Mechanism: binds to 23S ribosomal RNA in the 50S ribosomal subunit.
Available in both IV and oral forms (100% bioavailability).
Effective against MRSA, VISA, VRE, and penicillin-resistant Streptococcus pneumoniae.
Adverse Drug Reactions (ADRs):
- Myelosuppression leading to thrombocytopenia, especially after prolonged use (>2 weeks).
- Risk of superinfection, particularly yeast infections.
- Long courses may cause mitochondrial toxicity, resulting in peripheral or optic neuropathy.
Monitor drug-drug interaction with Monoamine Oxidase Inhibitors to prevent serotonin syndrome, especially with SSRIs.
Common dosing for complicated skin and soft tissue infections: 4 mg/kg daily (renal adjustment required).
For Staph aureus and MRSA bacteremia/right-sided endocarditis: 6 mg/kg daily (renal adjustment required).
Ineffective against pneumonia due to inactivation by pulmonary surfactant.
Additional ADRs include rhabdomyolysis and rare eosinophilic pneumonia.

Mupirocin (Bactroban)

Topical cream/ointment (2%) used for MRSA colonization eradication in nares.
Controversial effectiveness for long-term eradication.
Dosage: 0.5 grams in each nostril twice daily for 5 days.
Also used to treat impetigo or infected wounds.

Vancomycin

Primarily used for serious infections by beta-lactam resistant gram-positive organisms.
Administered through IV for systemic infections; oral form used for C. difficile colitis.
Avoid routine surgical prophylaxis and empirical therapy in febrile neutropenic patients unless there is clear evidence of gram-positive infection.
Dosing varies based on patient factors; commonly 1-15 gm every 12 hours, needing adjustment for renal insufficiency.
Monitoring involves measuring peak and trough levels, with the third dose taken at steady state after initiation.
Desired peak levels: 20-40 mcg/ml; troughs: 10-20 mcg/ml, except specific indications may warrant higher troughs.
Side effects include local reactions, nephrotoxicity, red-man syndrome, and various hematologic reactions like neutropenia and thrombocytopenia.

Spectrum and Indications of Vancomycin

Active against various gram-positive organisms, including MRSA, C. difficile colitis, and beta-lactam resistant strains.
Indications include serious infections in patients with a severe beta-lactam allergy and prophylaxis for major surgical procedures involving prosthetic materials.

Pharmacokinetics of Vancomycin

Poorly absorbed from the GI tract; IV only for systemic infections.
Distributed widely into body tissues; can penetrate the CSF during inflammation.
Excreted mostly unchanged via glomerular filtration.
Half-life ranges from 6-12 hours with dosing intervals based on renal function.

Additional Review Topics

Review mechanisms of action for different antibiotic classes.
Understand hallmark side effects associated with antibiotics.
Familiarize with antimicrobial coverage, including gram-positive, gram-negative, anaerobes, and atypical bacteria.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

This quiz covers the pharmacological details of Linezolid, including its class, mechanism of action, indications, and potential adverse reactions. Test your understanding of this important antibiotic and its role in treating resistant infections.