by VR Sreeraman on  August 3, 2009 at 8:38 AM Research News
 Higher Drug Doses Needed to Fight TB, Says Researchers
The traditional dose of tuberculosis medication given to patients is much too low in accordance with the modern-day physiques, say researchers.

Dr. Tawanda Gumbo, associate professor of internal medicine at UT Southwestern and the study's lead author have revealed that today's heavier physiques make the typical dose of a medication considered pivotal in treating tuberculosis largely ineffective.

"What really drives the variability of this particular drug is patient weight and gender, so in our simulations we took that into account," said Gumbo.

"What we found is that we're really using doses for very skinny people - 105 to 110 pounds. I haven't met many adults who are at that weight," Gumbo added. But treatment usually lasts six to 12 months and includes a combination of antibiotics such as Pyrazinamide, the drug examined in this study.

A new model developed at UT Southwestern uses cultured cells to gauge the effectiveness and proper dosage of anti-tuberculosis drugs.

"With this model, we can directly test molecules that have the potential to shorten therapy and go straight to coming up with the doses that you would use in patients," Gumbo said.

"What that means is that if you have a molecule that could cure TB in one month in this model, it stands a good chance that it would do the same in patients," the expert added.

When the UT Southwestern researchers began testing Pyrazinamide in the lab, they found that the concentration of the drug declined at a rate that matches the rate seen in patients.

"In patients, unlike in test tubes, it's not a constant concentration. A patient given multiple drugs degrades each of them at different rates," Gumbo said.

"Using this model, we can actually copy this concentration profile of the drugs to human-like exposures," the expert added.

Gumbo said that the doses traditionally given to tuberculosis patients are much too low suggesting that different doses are probably needed in different countries.

The findings appear in Antimicrobial Agents and Chemotherapy.

Source: ANI

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