Comment on: Pharmacokinetics of the co-administration of boceprevir and St John's wort to male and female healthy volunteers.

tration thresholds for rifampicin, isoniazid or pyrazinamide. We think that our study together with recent studies, not the least from Professor Gumbo and coworkers, calls for standard, routine therapeutic drug monitoring for all TB patients in Denmark; when embarking on a 6 month treatment of a deadly disease, it should be imperative—if the means and methods are available—to monitor whether the doses are correct. However, we still need further evidence on what drug concentrations are necessary, especially in combination treatment, as well as data on the relationships between drug concentrations and adverse effects.