MEASUREMENT OF MONTELUKAST AND LEVOCETIRIZINE SERUM LEVELS IN ALLERGIC RHINITIS PATIENTS AND INVESTIGATION OF THEIR EFFECTS ON TREATMENT

Objective: To measure montelukast and levocetirizine levels in blood samples from allergic rhinitis (AR) patients using a validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) and to investigate the relationship between both drugs and various parameters such as hematological parameters. Material and Method: Thirty-three AR patients were randomly assigned to receive montelukast (10 mg) and levocetirizine (5 mg) on admission and every evening for four weeks thereafter. Patients who were started on medication due to routine clinical necessity were included in the study. Results: Serum montelukast and levocetirizine levels of AR patients receiving 10 mg of montelukast and 5 mg of levocetirizine daily were 273.0 (12.6-4330.0) ng/mL and 362.0 (11.8-2152.0) ng/mL, respectively. A negative correlation was observed between montelukast levels and WBC, MCV, MCH, NEU, and LYM (p<0.05). Similarly, levocetirizine levels showed negative correlations with WBC (p<0.05), NEU (p<0.05), and LYM (p<0.005). In contrast, montelukast levels were positively correlated with disease duration (p<0.005) and levocetirizine levels (p<0.001). Additionally, levocetirizine levels demonstrated a positive correlation with disease duration (p<0.01). Conclusion: Montelukast and levocetirizine are clinically effective and have the capacity to improve the quality of life associated with rhinitis-asthma. The developed validated tandem mass spectrometric method has been successfully applied to measure serum montelukast and levocetirizine levels in AR patients.