Better lungs for better legs: novel bronchodilator effects in COPD.

rates), it could potentially be cost-effective or even cost-saving in the long run despite higher short-term treatment costs. Unfortunately, such benefits are difficult to estimate at the present time given the uncertainties surrounding the efficacy of rifampin. Aspler et al address this issue by assuming that 4 months of treatment with rifampin reduced the risk of active disease by at least 60%, approximately the same as 3 months of rifampin. While this minimum value seems reasonable, the requirement for wide variations in their estimate underscores the need for additional data on rifampin monotherapy. While unknown efficacy has been an issue, the major concern about use of rifampin for LTBI treatment has been the possibility of inadvertent treatment of active tuberculosis with rifampin mono-therapy which would lead to acquired rifampin monoresistance. Rifampin is a vital drug for tuberculosis treatment and, while patients infected with isoni-azid-monoresistant isolates can often be successfully treated with 6 months of therapy, patients infected with rifampin-monoresistant isolates usually require 12e18 months of treatment. To date, there has been a single case report of rifampin resistance apparently developing de novo on treatment for LTBI. 8 Non-adherence and poor absorption (due to vomiting) probably played a role in this case and no further cases have been reported in subsequent trials, so the real risk of rifampin resistance developing on therapy may be quite small. Nonetheless, thorough standardised evaluation for active tuberculosis prior to initiation of LTBI treatment and close observation while on treatment will be an essential component of any tuberculosis control programme that initiates large-scale rollout of the 4-month rifampin regimen. Any potential cost savings of this regimen would be quickly offset by the cost of the lengthy treatment for rifampin-mono-resistant disease. Furthermore, the phar-macokinetic interactions between rifampin and a number of other medications (which generally are not a significant issue with isoniazid) also pose a challenge to wide-scale implementation of this regimen. In particular, the use of rifampin for LTBI treatment will be limited in patients infected with HIV due to significant drugedrug interactions between rifampin and several classes of anti-retroviral drugs. 9 Regardless of these concerns, shorter better-tolerated regimens with higher completion rates in high-risk populations are needed to make progress towards tuberculosis elimination in the developed world. Given funding constraints for tuberculosis control, the cost-effectiveness of these regimens is of paramount importance to make them viable for public health practice. The study by Aspler et …