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Questions and answers about TB treatment
1. Is TB a curable disease?
Yes, TB is a curable disease, and usually with 6–9 months of treatment. Drug-resistant forms of TB are also curable albeit more difficult to treat. Treatment for drug-resistant TB can last up to two years and require medications that can cause serious side-effects. More information on TB treatment can be found here.
2. How long do I have to take TB medicines?
If this is the first time you are being treated for TB and you do not have drug-resistant TB, then treatment is usually 6 months. But there are variations on this in different parts of the world.
The first two months are called the intensive phase. During this phase you will usually take four drugs, hopefully in one pill. The drugs you will be given are likely to be isoniazid (or simply INH), rifampicin, pyrazinamide and ethambutol. Again, there might be different treatment regimens in your part of the world.
The next four months are called the continuation phase. During this phase you will take just isoniazid and rifampicin, hopefully still in one pill.
If this is the second time you are being treated for TB, you might also have to take daily injections of streptomycin and your treatment might by eight months instead of six. Also the continuation phase might be longer.
If you have been diagnosed with multidrug-resistant (MDR) or extensively drug-resistant (XDR) TB, the treatment regimen you will receive will be more complex and possibly even tailored for your individual needs. Treatment for MDR and XDR-TB is usually about two years.
3. What are the differences between rifapentine, rifabutin and rifampicin and when would you use which?
All three drugs are in the same class – rifamycins – meaning they use similar mechanisms to attack TB bacteria and have cross-resistance. Rifampicin (also called rifampin in the United States) is a very powerful TB drug capable of killing both slowly and rapidly replicating bacteria. Rifampicin is one of the most important drugs in the standard six-month, four-drug regimen for the treatment of drug-sensitive TB (DS-TB). But rifampicin interacts with many other medications, requiring dosing adjustments, including when used with important HIV medicines such as protease inhibitors. Rifabutin, like rifampicin, is used to treat DS-TB, but has fewer interactions with other drugs, making it a preferred treatment option for people who take HIV medications. Rifapentine – approved for the treatment of both active DS-TB and latent TB infection – has a longer half-life (stays in the body longer) than rifampicin and therefore may have the potential to shorten treatment for DS-TB. This long half-life has also allowed for the shortening and simplification of treatment for latent TB infection from 9 months of daily isoniazid to just 3 months of once-weekly isoniazid and rifapentine. However, despite future plans of expanded access, rifapentine is currently only registered in the United States.
4. What is the difference between rifampicin and rifampin?
There is no difference. They are the scientific same for the same drug. Rifampin is the name more commonly used in the United States, while rifampicin is more commonly used in Europe and South Africa.
5. I am taking TB medicines. My urine or tears have turned orange. Is this a problem?
This is common and almost always harmless. It is a side-effect of one of your TB medicines called rifampicin.
Questions and answers about diagnosing TB
1. Why are HIV-positive people with TB often smear-negative?
People who are coinfected with TB and HIV are up to 24–61% more likely to have smear-negative TB than are HIV-negative people. Up to 61% of people coinfected with HIV and TB generate smear-negative tests – in other words, an incorrect diagnosis.
Simple explanation
TB is expelled into the sputum when TB-infected cells are killed. In immune compromised people, fewer TB cells are killed by the immune system, so less TB gets into the sputum.
Technical explanation
As CD4 T cells are lost due to and compromised by HIV infection, CD8 T cells lose the directional support they need to do their job of killing TB-infected cells because they are no longer being told to kill TB-infected cells. TB is expelled into the sputum when TB-infected cells are killed. Therefore, the chance of smear-negative TB increases because fewer TB bacilli are released in the sputum. This means that TB is not being released into the sputum, so despite the fact that someone may have TB in his or her system it is not detected using sputum-smear microscopy.
Questions and answers about TB prevention
1. What is isoniazid preventative therapy (IPT)?
This is when a person, usually HIV-positive, takes a drug called isoniazid to reduce the risk of getting TB. IPT has been shown to only benefit people who are tuberculin skin test positive.
2. I am HIV-positive and I work in a prison or hospital where many people are ill with TB. Should I take isoniazid preventative therapy (IPT)?
First you should have something called a tuberculin skin test. If this test is positive, then you should consider taking isoniazid preventative therapy.
Studies show that taking isoniazid reduces the risk of you becoming ill with TB.
