Meds, Mind, Body & Benefits > Questions About Treatment & Side Effects

INH prophylaxis?


Like a lot of people (maybe most, I think 90% even) who've lived in Asia or Africa for a long period of time, I show a positive Mantoux (PPD) test. It's not something I've thought about or worried about. X-ray is of course fine; in 2000, a chest and abdomen MRI was also completely clear. My mother, who's a physician, laughs when she hears that it's the test is used to decide (at American colleges anyway) whether or not to prescribe/offer isoniazid. So I've never thought about INH therapy.

But should I think about it? It's been just about a year since I was infected. My numbers are good. March: CD4 757, 38%, VL 70 copies; July: CD4 917, 40%, 53 copies. I have no desire to take nine months of isoniazid when I'm otherwise healthy, not immunocompromised. There don't seem to clear protocols about this. I read vague things like people who are HIV-positive are "much likelier" to develop active tuberculosis infection. How much likelier? When? At what CD4 count?

I know thirtysomething (Raj) started taking INH immediately after being diagnosed positive, and his numbers are even "better" than mine. I'm not sure whether this was necessary or doctors just taking the expedient (and obvious, and possibly safer) route.

If anyone has information or experience with this, or an opinion even, please do share.



These are from the CDC websites:

An estimated 10-15 million Americans are infected with TB bacteria, with the potential to develop active TB disease in the future. About 10 percent of these infected individuals will develop TB at some point in their lives. However, the risk of developing TB disease is much greater for those infected with HIV and living with AIDS. Because HIV infection so severely weakens the immune system, people dually infected with HIV and TB have a 100 times greater risk of developing active TB disease and becoming infectious compared to people not infected with HIV. CDC estimates that 10 to 15 percent of all TB cases and nearly 30 percent of cases among people ages 25 to 44 are occurring in HIV-infected individuals.

This high level of risk underscores the critical need for targeted TB screening and preventive treatment programs for HIV-infected people and those at greatest risk for HIV infection. All people infected with HIV should be tested for TB, and, if infected, complete preventive therapy as soon as possible to prevent TB disease.

From: The Deadly Intersection Between TB and HIV

TB disease occurs among HIV-infected persons at all CD4 counts. The clinical manifestations might be altered depending on the degree of immunosuppression. Those with more advanced immunosuppression (CD4 <200) are more likely to have extrapulmonary or disseminated disease. In areas where TB is endemic, certain patients have higher CD4 counts at the time HIV-related TB disease develops; in countries with low rates of TB disease (e.g., United States and countries in Western Europe), more patients have advanced HIV disease at the time TB develops.

TB disease in persons with HIV-1 infection can develop immediately after exposure (i.e., primary disease) or as a result of progression after establishment of latent TB infection (i.e., reactivation disease). Primary TB has been reported in certain group outbreaks, particularly in persons with advanced immune suppression, and might account for one third or more of cases of TB disease in the HIV-infected population.

Progression to disease among those with latent TB infection is more likely among HIV-infected than in HIV-uninfected persons. HIV-uninfected persons with a positive tuberculin skin test (TST) result have a 5% - 10% lifetime risk for developing TB, compared with a 7% - 10% annual risk in the HIV-infected person with a positive TST result.

From: Treating Opportunistic Infections Among HIV-Infected Adults and Adolescents

My advice: consider taking the INH now while your immune system is still intact and able to assist in eliminating the latent TB infection.  This will help prevent reactivation to TB disease later.

Hi Jay,

If you PPD test is positive, I strongly suggest you start INH asap. And it's not that bad as you think. I was petrified when I started INH in March, but it's pretty cool and luckily I have had no side effects.



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