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[CAPE TOWN] The antiretroviral drug efavirenz has been recommended for tuberculosis patients who then contract HIV.
Researchers compared the effectiveness of the antiretroviral drugs efavirenz and nevirapine in 4,000 South African HIV patients. Some already had tuberculosis (TB) and were taking rifampicin.
Nevirapine — the cheaper of the two drugs — was found to be less effective in patients with existing TB, with higher HIV loads in their blood than those on efavirenz.
HIV-infected patients who were already on antiretroviral drugs when they subsequently developed TB were unaffected, highlighting the complexity of treating concurrent HIV and TB infections.
Researchers from the Western Cape provincial health department, Médecins Sans Frontières and the University of Cape Town (UCT) published their findings in the Journal of the American Medical Association (6 August).
Study leader Andrew Boulle warns that the research is not a rejection of nevirapine, which is popular in the developing world because of its low cost, simplicity of use and its safety for pregnant HIV-infected women.
"Four out of five of our patients in the study continued to do well on nevirapine," said Boulle, a public health specialist from the School of Public Health and Family Medicine at UCT.
The long-standing anti-TB drug rifampicin slows down the liver’s ability to process nevirapine, making the anti-HIV drug less effective and causing an increase in virus levels.
Efavirenz is only slightly affected by rifampicin, said Katherine Hildebrand, another UCT researcher. But it costs twice the price of nevirapine. "We need to get the price of efavirenz down in places with high HIV/TB co-infection," she told SciDev.Net.
The research also disproves earlier assumptions that people with both TB and HIV may need increased doses of efavirenz. Researchers found that efavirenz in normal doses was ideal for HIV patients regardless of whether they had TB or not.
"Efavirenz should be used unless there are compelling reasons not to use it. Unfortunately many developing countries do not have access to efavirenz which is more expensive," said Gary Maartens from UCT medical school’s clinical pharmacology division. Botswana and South Africa both use efavirenz extensively.
Journal of the American Medical Association 300, 530 (2008)