Subtherapeutic antiretroviral plasma concentrations in routine clinical outpatient HIV care

Monique M.R. De Maat, Alwin D.R. Huitema, Jan W. Mulder, Pieter L. Meenhorst, Eric C.M. Van Gorp, Albert T.A. Mairuhu, Jos H. Beijnen

Onderzoeksoutput: Bijdrage aan tijdschriftArtikelpeer review

33 Citaten (Scopus)


The objective of this study was to evaluate plasma concentrations of nonnucleoside reverse transcriptase inhibitors (NNRTIs) and protease inhibitors (PIs) within several dosing schemes in a cohort of HIV-infected patients in routine clinical practice and to find possible explanations for subtherapeutic plasma concentrations. Patients were included if a PI or NNRTI was part of their antiretroviral regimen, at least one plasma concentration was obtained, and a complete medication overview from community pharmacy records was available. The study period was from January 1998 to September 2001. Each plasma concentration was related to median plasma concentrations of a pharmacokinetic reference curve, yielding a concentration ratio (CR). A cutoff CR was defined for each antiretroviral drug per specific regimen, discriminating between ≥therapeutic and subtherapeutic concentrations. For the patients with subtherapeutic concentrations, it was sorted out whether drug interactions, adverse events and self-reported symptoms, or nonadherence could be the cause of the lower than expected plasma concentration. Ninety-seven HIV-infected patients fulfilled the criteria. During the defined period, 1145 plasma concentrations were available (median, 11; interquartile range, 8-14). Three hundred fourteen (27.4%) plasma concentrations were classified subtherapeutic. Drug interactions (2; 0.6%), adverse events and self-reported symptoms (67; 21.3%), and nonadherence (14; 4.5%) could only partly explain the subtherapeutic drug levels. Consequently, a large number of the subtherapeutic plasma concentrations (73.6%) remained inexplicable. A high number of subtherapeutic plasma concentrations were observed. No clear causes were found; thus, corrective measures will be difficult to employ. Therefore, therapeutic drug monitoring (TDM) must maintain its crucial place in routine clinical care to be able to identify patients who need extra attention so that therapeutic plasma concentrations are achieved.

Originele taal-2Engels
Pagina's (van-tot)367-373
Aantal pagina's7
TijdschriftTherapeutic Drug Monitoring
Nummer van het tijdschrift3
StatusGepubliceerd - jun. 2003
Extern gepubliceerdJa


Duik in de onderzoeksthema's van 'Subtherapeutic antiretroviral plasma concentrations in routine clinical outpatient HIV care'. Samen vormen ze een unieke vingerafdruk.

Citeer dit