CHENNAI: In the battle against multi-drug resistant tuberculosis, the last line of defence seems one that can be easily breached. A key drug prescribed to treat the complex bacterial infection is of substandard quality, a study conducted in eight districts in Tamil Nadu has found.
The study, undertaken by National Institute for Research in Tuberculosis (NIRT), Chennai, found that the content of cycloserine — a second-line anti-TB drug — was below the accepted standard set by the World Health organization in all eight of the districts surveyed, even as most other drugs met the prescribed norms. All the samples were collected from centres that come under the Revised National TB Control Programme (RNTCP).
While experts say the quality of the drug supplied and storage conditions have always been a cause for concern, this is the first time it has been systematically documented. "Cycloserine has been in the market for 30 to 40 years. It has always been susceptible to degradation, but the issue is of greater concern now with the rise in cases of multi-drug resistant tuberculosis (MDR-TB) and the increase in the number of people dependent on it," said Dr Soumya Swaminathan, director of NIRT.
For the study, researchers collected 10 samples of seven key anti-TB drugs from the district TB centre, TB unit, designated microscopy centres and Directly Observed Treatment (DOTS) providers in eight districts.
"We collected the drugs over four or five months. Most of the drugs met the prescribed standards but the content of cycloserine in all the districts was a serious concern. This has largely to do with the conditions in which they were stored," said Dr Geetha Ramachandran, who led the study. "The drugs are extremely sensitive to high temperature. Despite this, at quite a few centres we found there were no refrigerators," she said. While the prescribed amount of the drug — considered an important component in the DOTS regimen — was 250mg, researchers found that the content of the key ingredient was as low as 108mg in some centres.
Although experts have ruled out side effects, they say treatment could be ineffective, putting more people at risk of contracting the infection. "We have presented our findings to RNTCP officials. Treatment should be therapeutic and patients deserve effective treatment," said Dr Ramachandran. "Gross deterioration of the drug during transit and storage in the tropics has been previously reported, and this was attributed to high humidity."
The cycloserine tablets analysed for the study were collected from DOT providers' homes, many of whom could afford to store the drug only at room temperature. "Most of them lived in thatched huts. The problem can be solved to some extent by storing the tablets in refrigerators in the district centres and giving no more than a week's supply to the DOT provider at a time,' the study said.
State government officials admit there was degradation at the lower level, but said monitoring the drugs isn't easy. "All our second line drugs are stored in an air-conditioned environment in shops but monitoring at the community level isn't always easy. There are thousands of DOTS providers and 800 for MDR-TB alone. It isn't possible to equip everyone with refrigerators, but necessary steps will be taken from our end," said Dr K Arunagiri, state TB control officer.
TB expert Dr Manjula Datta said changes need to be made at the manufacturers' level. "RNTCP must put pressure on the manufacturers to change their formulation. Increasing the dosage of the drug won't help as there are several logistical issues," said Dr Datta.
Source: The Times of India