PK and PD of Drugs for Nontuberculous Mycobacterial Diseases in Dutch Patients

Inclusion Criteria: * currently treated for NTM infection or recently diagnosed with NTM infection starting treatment at University Centre for Chronic Diseases Dekkerswald (Groesbeek), Centre for Revalidation Beatrixoord (Haren), or other outpatient clinics in The Netherlands. * Diagnosis and treatment according to American Thoracic Society (ATS) criteria for NTM infections. Patients with pulmonary NTM infections (possible with extrapulmonary localizations as well) are eligible * Treated with at least rifampicin and ethambutol and optionally with isoniazid, clarithromycin or azithromycin on a daily basis * Age at least 18 years * Patient has been using drugs for at least two weeks when steady state concentrations of the used drugs are expected * Informed consent has been signed Exclusion Criteria: * The medical state of the patients does not allow inclusion according to the physician in attendance. * The patients' clinical parameters urge immediate cessation of drugs. * The patient is pregnant. * Significant hepatic or renal dysfunction based on chemistry parameters (grade 1 according to an international adverse event grading system, see http:/ctep.cancer.gov) or symptomatic liver dysfunction (nausea and vomiting). * Patients with cystic fibrosis, since these show deviating pharmacokinetics for many drugs. * Patients with HIV infection, since these may show deviating pharmacokinetics for the drugs used in NTM disease.