Drug Interaction Study Between Linezolid and Clarithromycin in Tuberculosis Patients

The Pharmacokinetic Effect of Clarithromycin on the AUC0-12h of Linezolid in Multidrug-resistant and Extensively Drug-resistant Tuberculosis (MDR/XDR-TB) Patients

Future patients might benefit from a combination of linezolid (LIN) and clarithromycin (CLA) in the treatment of Multidrug-resistant and Extensively Drug-resistant Tuberculosis (MDR/XDR-TB) due to possible synergistic activity as shown in in vitro experiments in different Mycobacteria strains. The investigators observed increased LIN serum levels in three cases after combining LIN and CLA of which the investigators described one in a case report (Bolhuis et al). The investigators suggest to conduct a prospective pharmacokinetic study in MDR- and XDR-TB patients to quantify the above described interaction between LIN and CLA.

Inclusion Criteria:

• Age ≥18 years old
• Signed informed consent
• Diagnosis of MDR/XDR-TB confirmed with standard microbiological criteria (culture-based, molecular or both)
• Treatment with linezolid 300mg twice daily per os.

Exclusion Criteria:

• Hypersensitivity to: linezolid, clarithromycin, erythromycin, or any macrolide antibiotics, or any of the excipients of linezolid or clarithromycin.
• Concomitant use with astemizole, cisapride, ergotamine derivatives (dihydroergotamine, ergotamine), monoamine oxidase inhibitors (phenelzine, isocarboxazid, selegiline, or moclobemide), pimozide, or terfenadine.
• Pregnancy or breast-feeding.
• Hypokalemia
• Concomitant use of other P-gp inhibitors/inducers, e.g. amiodarone, verapamil, digoxin, tipranavir/ritonavir, lovastatin, tariquidar, itraconazole, dipyridamol, erythromycin, ritonavir, quinidine.