From the Guidelines
Monthly complete blood counts should be assessed while the patient is receiving linezolid, in addition to monthly screening for peripheral neuropathy. This is based on the most recent evidence from the American Journal of Respiratory and Critical Care Medicine 1, which highlights the importance of monitoring for potential adverse effects of linezolid, particularly bone marrow suppression and peripheral neuropathy. The key points to consider when monitoring patients on linezolid therapy include:
- Bone marrow suppression, with thrombocytopenia being the most common hematologic adverse effect, followed by anemia and leukopenia 1
- Peripheral neuropathy, which may not be reversible upon discontinuation of the medication 1
- Optic neuropathy, which can occur with extended use of linezolid 1
- Lactic acidosis, which is a rare but potentially serious adverse effect 1
- Serotonin syndrome, which can occur in patients taking concurrent selective serotonin-receptor inhibitors 1 It is essential to weigh the benefits of linezolid therapy against the potential risks and to closely monitor patients for signs of adverse effects, particularly those with pre-existing cytopenias, those receiving concomitant myelosuppressive medications, or those with renal insufficiency. If significant decreases in blood cell counts occur, discontinuation of linezolid should be considered, especially if severe myelosuppression develops. Overall, the monitoring of complete blood counts and screening for peripheral neuropathy are crucial components of linezolid therapy, as recommended by the American Journal of Respiratory and Critical Care Medicine 1.
From the FDA Drug Label
Complete blood counts should be monitored weekly in patients who receive linezolid, particularly in those who receive linezolid for longer than two weeks, those with pre-existing myelosuppression, those receiving concomitant drugs that produce bone marrow suppression, or those with a chronic infection who have received previous or concomitant antibiotic therapy The bloodwork that should be monitored on linezolid is:
- Complete blood counts, which should be done weekly, especially in patients who:
- Receive linezolid for more than two weeks
- Have pre-existing myelosuppression
- Receive concomitant drugs that produce bone marrow suppression
- Have a chronic infection and have received previous or concomitant antibiotic therapy 2
From the Research
Bloodwork Monitoring for Linezolid
The following bloodwork should be monitored when a patient is on linezolid:
- Complete blood counts (CBC) should be monitored weekly in patients receiving linezolid for more than 14 days to check for signs of myelosuppression, such as thrombocytopenia, anaemia, and neutropenia 3
- Serum lactate concentrations should be checked regularly, especially in patients on long-term use (>6 weeks), to monitor for lactic acidosis 4, 5
- Monitoring of serum lactate levels can help in early detection of lactatemia and enable rapid rescue 5
Special Considerations
- Patients receiving linezolid for more than 28 days should be monitored for signs of peripheral and optic neuropathy 6
- Therapeutic Drug Monitoring (TDM) can be useful in patient populations with sparse clinical data or known alterations in pharmacokinetics, including children, patients with renal insufficiency, and patients taking co-medications known to interact with linezolid 7