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Evaluation of saliva as a potential alternative sampling matrix for therapeutic drug monitoring of levofloxacin in patients with multidrug-resistant tuberculosis

Ghimire, S., Maharjan, B., Jongedijk, E. M., Kosterink, J. G. W., Ghimire, G. R., Touw, D. J., van der Werf, T. S., Shrestha, B. & Alffenaar, J. W. C., 1-May-2019, In : Antimicrobial Agents and Chemotherapy. 63, 5, 10 p., ARTN e02379-18.

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Saliva may be a useful alternative matrix for monitoring levofloxacin concentrations in multidrug-resistant tuberculosis (MDR-TB) patients. The objectives of this study were (i) to evaluate the correlation between plasma and salivary levofloxacin (Lfx) concentrations in MDR-TB patients and (ii) to gauge the possibility of using saliva as an alternative sampling matrix for therapeutic drug monitoring of Lfx in areas where TB is endemic. This was a prospective pharmacokinetic study that enrolled MDR-TB patients receiving levofloxacin (750- to 1,000-mg once-daily dosing) under standardized treatment regimen in Nepal. Paired blood and saliva samples were collected at steady state. Lfx concentrations were quantified using liquid chromatography-tandem mass spectrometry. Pharmacokinetic parameters were calculated using noncompartmental kinetics. Lfx drug exposures were evaluated in 23 MDR-TB patients. During the first month, the median (interquartile range [IQR]) areas under the concentration-time curve from 0 to 24 h (AUC 0–24 ) were 67.09 (53.93 to 98.37) mg ⋅ h/liter in saliva and 99.91 (76.80 to 129.70) mg ⋅ h/liter in plasma, and the saliva plasma (S/P) ratio was 0.69 (0.53 to 0.99). Similarly, during the second month, the median (IQR) AUC 0–24 were 75.63 (61.45 to 125.5) mg ⋅ h/liter in saliva and 102.7 (84.46 to 131.9) mg ⋅ h/liter in plasma, with an S/P ratio of 0.73 (0.66 to 1.18). Furthermore, large inter- and intraindividual variabilities in Lfx concentrations were observed. This study could not demonstrate a strong correlation between plasma and saliva Lfx levels. Despite a good Lfx penetration in saliva, the variability in individual saliva-to-plasma ratios limits the use of saliva as a valid substitute for plasma. Nevertheless, saliva could be useful in semiquantitatively predicting Lfx plasma levels. (This study has been registered at ClinicalTrials.gov under identifier NCT03000517.)
Original languageEnglish
Article numberARTN e02379-18
Number of pages10
JournalAntimicrobial Agents and Chemotherapy
Volume63
Issue number5
Publication statusPublished - 1-May-2019

    Keywords

  • Levofloxacin, Pharmacokinetics, Plasma, Saliva, Tuberculosis

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