Evidence for promoting fixed-dose combination drugs in tuberculosis treatment and control: a review [Unresolved issues]

Uptake of fixed-dosed combinations (FDCs) of anti-tuberculosis drugs remains low worldwide, despite decades of recommendations. FDCs are thought to be important tools for tuberculosis (TB) control and drug resistance (DR) prevention. However, evidence relating to this is limited. This article provides a critical review of the most relevant studies on anti-tuberculosis FDCs. The majority of published studies have sought to demonstrate that FDCs and single drugs have similar efficacy. This hypothesis has been proved with relation to similar sputum conversion, cure and relapse rates in a range of studies over the last 20 years using FDCs of two, three and four anti-tuberculosis drugs. However, one of the most relevant features of FDCs, the prevention of DR, has been addressed in only one study. Nevertheless, based on their similar efficacy, user-friendliness, lower costs, and operational and logistical advantages, generalised use of FDCs should continue to be recommended.