Blood pressure drug may quicken TB treatment

Researchers with Johns Hopkins University recently found that a drug used to treat high blood pressure could speed up tuberculosis treatment when added to standard antibiotics, according to a study published on Sunday.

The study, which was published in the American Journal of Respiratory and Critical Care Medicine, found that verapamil, a calcium channel blocker, accelerated the killing of TB bacteria 10-fold after two months of treatment in mice. Test animals were cured in four months as opposed to the usual six.

"Our results show that verapamil is a good drug candidate as an add-on therapy with antibiotics for TB, a global disease in urgent need of new treatment options," William Bishai, the study's senior investigator, said.

Verapamil was added to a standard antibiotic regimen of daily doses of isoniazid, rifampin and pyrazinamide for two months, followed by half doses of isoniazid and rifampin for four months. After four months of therapy, half of the lung tissue samples from mice receiving verapamil had zero bacteria counts. All tissue samples in mice not on verapamil remained positive for TB.

Verapamil is known to make bacteria more susceptible to antibiotics and killing by immune cell macrophages. The precise workings of the drug's effects on bacteria remain unknown.

Clinical trials are scheduled to begin later this year in India to test verapamil in human TB treatment. By reducing treatment time, the blood pressure medication could make it easier for infected people to finish their drug therapy as prescribed. When TB treatment is interrupted or if people stop taking medication, TB strains can become drug-resistant.