A wide variation in the dosages and forms of medicines prescribed by private physicians to patients with tuberculosis (TB) in developing countries could lead to the development of more drug-resistant strains of the bacterial infection, according to a study published online Wednesday in PLoS One, the Financial Times reports (Jack, 5/4).

Researchers from the TB Alliance and health care market research firm IMS Health examined treatment data from 10 countries that “carry 60% of the world’s TB burden (Bangladesh, China, India, Indonesia, Pakistan, Philippines, Russian Federation, South Africa, Thailand, and Viet Nam),” Scoop writes (Shukla, 5/4). They found that “[m]ore than a third of TB medicines in the private sector are supplied at strengths not recommended by international guidelines” and “[o]ver half of TB medicines are also provided as individual loose tablets rather than mixed together into ‘fixed dose combination’ pills that are easier to take, increasing the risk that patients will not receive the full range of recommended drugs as prescribed,” the Financial Times notes (5/4).

The study found 111 different first-line TB drug dosages and combinations being used in the private sector, compared with the 14 deemed necessary by the Stop TB Partnership’s Global Drug Facility, according to a TB Alliance press release.

“The private sector is keeping alive the confusion that existed previously in the public sector,” William Wells, the study’s lead author and director of Market Access at the TB Alliance, said, adding, “With this new baseline understanding of the TB drug market, we can no longer ignore the private sector’s critical role in the access equation for TB treatment and in the task of protecting both current drugs and new regimens from the development of resistance” (5/4).

The researchers concluded, “Private TB drug markets in several [high-burden countries] are substantial, stable, and complicated. This calls for appropriate policy and market responses, including expansion of Public-Private Mix (PPM) programs, greater reach, flexibility and appeal of public programs, regulatory and quality enforcement, and expansion of public [multi-drug resistant]-TB treatment programs” (Wells et al., 5/4).