%0 Journal Article %A Noor Alsaad %A Richard van Altena %A Arianna D. Pranger %A Dick van Soolingen %A Wiel C.M. de Lange %A Tjip S. van der Werf %A Jos G.W. Kosterink %A Jan-Willem C. Alffenaar %T Evaluation of co-trimoxazole in the treatment of multidrug-resistant tuberculosis %D 2013 %R 10.1183/09031936.00114812 %J European Respiratory Journal %P 504-512 %V 42 %N 2 %X Co-trimoxazole (SXT), a combination of sulfamethoxazole and trimethoprim, has shown in vitro activity against Mycobacterium tuberculosis. However, the pharmacokinetic and pharmacodynamic parameters of SXT in multidrug-resistant (MDR) tuberculosis (TB) are, thus far, lacking. Therefore, we evaluated its pharmacokinetics and drug susceptibility, along with its tolerability during treatment. Based on drug susceptibility testing, MDR-TB patients received SXT as a part of their MDR treatment. The pharmacokinetic parameters of sulfamethoxazole, the effective component of SXT against M. tuberculosis, were evaluated. The ratio of the area under the curve from 0 to 24 h (AUC0–24) to minimum inhibitory concentration (MIC) was used as the best pharmacokinetic/pharmacodynamic parameter to predict the efficacy of sulfamethoxazole. Adverse effects of SXT were also evaluated. 10 patients with MDR-TB (one of whom had extensively drug-resistant TB) received 480 mg of SXT with a median dosage of 6.5 mg·kg−1 of SXT (range 6.1–6.8 mg·kg−1) once daily for a median treatment period of 381 days (range 129–465 days). In two patients, the dose was escalated to 960 mg. The free AUC0–24/MIC of sulfamethoxazole exceeded 25 in only one patient. SXT was safe and well-tolerated, except for one patient who had gastrointestinal side-effects after receiving 960 mg of SXT. Additional studies are needed to find the pharmacokinetic and pharmacodynamic targets, and consequently to set the optimal dose, of SXT for MDR-TB treatment. %U https://erj.ersjournals.com/content/erj/42/2/504.full.pdf