Text box 2.
Recommendations for TDM in NTM disease
| Efficacy | Information on PK/PD targets on drugs used for NTM is scarce. TDM for efficacy is preferably guided by PK/PD targets but if these are lacking it would help to target normal exposure in patients with low exposure not responding to therapy |
| Toxicity | In the case of presumed drug-related toxicity, dose adjustment is suggested when high drug concentrations are observed at a standard dose |
| Drug–drug interactions | Drug–drug interactions can be managed as usual and TDM can be used to verify if exposure is within the normal range for that particular drug |
| Renal or hepatic function problems | For renally excreted or hepatically metabolized drugs, dosages can be adjusted as recommended by guidelines and TDM can be used to verify if exposure is within the normal range for that particular drug |
| Comorbidities (e.g., diabetes mellitus, HIV, CF) | As treatment in patients with comorbidities is often accompanied with complications, it is recommended to evaluate drug exposure in situations where these may arise |
| Sampling | At least 2 samples should be collected during the dose interval to assess drug exposure. A single sample often does not provide sufficient information as delayed absorption on reduced clearance is imperceptible |
CF cystic fibrosis, HIV human immunodeficiency virus, NTM nontuberculous mycobacteria, PD pharmacodynamic, PK pharmacokinetic, TDM therapeutic drug monitoring