Objective: Linezolid is one of the key drugs for the treatment of multidrug-resistant/extensively drug-resistant tuberculosis (MDR/XDR-TB). We aimed to describe the incorporation of the Michigan Neuropathy Screening Instrument (MNSI) and serum trough concentration as screening tools for neurotoxicity in the management of MDR/XDR-TB patients receiving a linezolid-based treatment regimen in Shenzhen, China.
Methods: A total of 73 patients on a linezolid-containing anti–MDR/XDR-TB regimen were prospectively enrolled. The MNSI was used for peripheral neuropathy screening. Optic neuropathy was diagnosed by ophthalmologists. Serum trough concentration was recorded and its relationship with neuropathy analyzed.
Results: Of all patients, neuropathy was observed in 40% (29) during anti-TB treatment. Of these, 20 (69%) had peripheral neuritis, seven (24%) optic neuritis, and two (7%) both. Serum trough concentration > 2 mg/L was observed in 17 (59%) patients with neuropathy and 13 (30%) patients without neuropathy. There was a significant statistical difference between the two groups (P =0.013). Time to onset of neuropathy from initiation of the linezolid-containing regimen was within 2 months for eight (28%) patients, 2– 6 months for 18 (62%) patients, and > 6 months for three (10%) patients. Sixteen (55%) patients were adjusted to a lower dose of 300 mg linezolid daily. Four (14%) patients had linezolid permanently removed from their regimen.
Conclusion: Neuropathy is a commonly reported adverse event associated with long-term use of linezolid. MNSI and serum trough–concentration monitoring can be adopted as simple screening tools for early detection of neuropathy to balance linezolid efficacy and tolerability.
Keywords: linezolid, MDR/XDR-TB, neuropathy, MNSI, serum trough concentration