Important note: Information in this article was accurate in December 2000. The state of the art may have changed since the publication date.
After people with AIDS have recovered from a life-threatening infection, doctors usually prescribe reduced doses of antibiotics, antifungals or antiviral drugs to suppress the infection. This is certainly the case for infections such as:
If preventative doses of antimicrobial drugs are not used, the infections tend to recur and again become life-threatening. However, suppressive doses of antibiotics are not usually given to HIV+ people who have recovered from tuberculosis (TB).
Wondering whether such people may be at high risk for a second bout of TB, doctors in Haiti and New York conducted a two-year study to compare the effects of post-treatment antibiotic therapy with isoniazid vs. placebo in people with and without HIV infection. Not surprisingly, those people who took maintenance therapy with isoniazid were significantly less likely to develop TB than people who received placebo. The results from this study suggest that maintenance therapy using isoniazid could be considered for some HIV+ people who have recovered from TB.
Researchers enrolled 233 adults (116 female, 117 male) for this study. All subjects had recovered from their first bout of TB before being enrolled. Moreover, these subjects had previously been educated about the importance of taking all of their medications as directed. While they were being treated for TB, their ability to take medication as instructed was monitored. About 64% of the HIV+ subjects had symptoms of HIV/AIDS before entering the maintenance study.
Subjects received either 300 mg of isoniazid and 40 mg of vitamin B6, both daily for one year, or placebo and 40 mg/day of vitamin B6, also for one year. Vitamin B6 is used to help reduce the toxicity of isoniazid. On average, subjects were monitored for about two years.
The breakdown of recurring TB cases by HIV status was as follows:
Those HIV positive people who received placebo were about six times more likely to develop TB than people who received isoniazid. This difference was also statistically significant.
The risk of developing a second episode of TB was strongly linked to having symptoms of HIV disease before the first episode of TB. Indeed there were no recurring cases of TB in HIV positive people who did not have symptoms of HIV disease.
The number of deaths in the HIV positive group — 34 people — was evenly divided between those who received isoniazid and those who received placebo.
In this long study, isoniazid clearly helped prevent a second bout of TB in HIV positive people. This was especially the case in those people who had symptoms of HIV disease before their first episode of TB. The study's results may not apply to all people with HIV infection. People who have access to free or subsidized highly active antiretroviral therapy (HAART) and who adhere to and respond immunologically to HAART may not need to follow the protocol in this study. This is because the improvement in the immune system that accompanies the use of HAART has allowed some PHAs to stop taking maintenance therapy for many complications of AIDS, including MAC, PCP and CMV. Researchers in Taiwan have found that some PHAs treated with HAART have regained immunity to TB, at least according to lab experiments on their CD4+ and CD8+ cells. Further studies are needed to find out whether guidelines should be developed as to if and when PHAs can discontinue TB maintenance.
Another issue is that of adherence to TB medication. The subjects who received TB maintenance therapy had been educated about the importance of adherence and at times their pill-taking behaviour was monitored. These subjects therefore are not representative of the average PHA with TB or who is at risk for recurring TB. Results may be different in PHAs who do not receive education and support for TB medication adherence.
1. Fitzgerald DW, Desvarieux M, Severe P, et al. Effect of post-treatment isoniazid on prevention of recurrent tuberculosis in HIV-1-infected individuals: a randomized trial. Lancet 2000;356:1470-1474.
2. Hsieh S-M, Hung C-C, Pan S-C, et al. Restoration of cellular immunity against tuberculosis in patients co-infected with HIV-1 and tuberculosis with effective antiretroviral therapy: assessment by determination of CD69 expression on T cells after tuberculin stimulation. Journal of Acquired Immune Deficiency Syndromes 2000; 25(3):212-220.
20001210
CATE11306
Copyright © 2000 - TreatmentUpdate. Reproduced with permission. Reproduction of this article (other than one copy for personal reference) must be cleared through the Editor, The Canadian AIDS Treatment Information Exchange, 555 Richmond St. West, Suite 505, Box 1104, Toronto, ON, M5V 3B1 • Phone: 416-203-7122 • Toll Free: 1-800-263-1638 • Fax: 416-203-8284 http://www.catie.ca.
ÆGiS is made possible through unrestricted grants from Boehringer Ingelheim, Elton John AIDS Foundation, iMetrikus, Inc., the National Library of Medicine, and donations from users like you. Always watch for outdated information. This article first appeared in 2000. This material is designed to support, not replace, the relationship that exists between you and your doctor.
ÆGiS presents published material, reprinted with permission and neither endorses nor opposes any material. All information contained on this website, including information relating to health conditions, products, and treatments, is for informational purposes only. It is often presented in summary or aggregate form. It is not meant to be a substitute for the advice provided by your own physician or other medical professionals. Always discuss treatment options with a doctor who specializes in treating HIV.
