OBJECTIVE: To evaluate the impact of Linezolid therapy on haematological parameters, including haemoglobin levels, total leukocyte count, and platelet count, and identify patterns and predictors of haematological toxicity.

METHODS: This prospective, observational study was conducted at the Department of Pharmacology after obtaining institutional ethics committee approval. Thirty-six patients over 18 years who had received Linezolid therapy for at least five days were enrolled. Patients with pre-existing haematological disorders, recent chemotherapy, viral diseases, pregnancy, or hypersensitivity to Linezolid were excluded. Baseline haematological parameters were recorded and compared to values after 5–7 days of therapy. Haematological toxicity was defined as thrombocytopenia (≥25% reduction in platelet count or ≤125×10⁹/L), anaemia (>25% reduction in haemoglobin), and leukopenia (<4×10⁹/L). Data were analysed using paired t-tests and the Wilcoxon Signed Ranks Test, with p < 0.05 considered statistically significant.

RESULTS: The mean age of participants was 49.39 ± 13.43 years, with 63.9% males. Linezolid therapy resulted in significant reductions in haemoglobin (12.71 ± 1.64 g/dL to 11.30 ± 1.74 g/dL; p = 0.0034), total leukocyte count (15.15 ± 3.14×10⁹/L to 10.96 ± 3.48×10⁹/L; p = 0.0011), and platelet count (361.50 ± 75.63×10⁹/L to 306.53 ± 76.22×10⁹/L; p = 0.0021). Thrombocytopenia occurred in 33.33% of patients, anaemia in 16.67%, and leukopenia in none. Longer therapy duration was associated with increased toxicity risk.

CONCLUSION: Linezolid therapy significantly impacts haematological parameters, with thrombocytopenia being the most frequent adverse effect. Regular monitoring and individualised treatment strategies are essential for minimising haematological toxicity and optimising Linezolid's clinical use.