Antibiotics to treat TB have been available since the 1950s, and, when used correctly they can cure TB in people with HIV.

Like HIV, treating TB successfully means taking a combination of drugs at the right time and in the right way. Treatment is usually for six months. In some cases, people may have to take treatment for nine months or a year.

If people either don't take their treatment properly or stop taking their pills once they start to feel better, this can lead to TB becoming resistant to some or all of the drugs used to treat it. This means that the drugs stop working on that type of TB.  Drug-resistant TB is becoming more common in many places in the world. Resistant TB can need treatment for a longer time, often for two years.

Anti-TB drugs can also interact with some other drugs, including those used to treat HIV, and can have side-effects. It is important to let your doctor know all the medicines you are taking so they can avoid possible interactions. If there is a chance that medicines you are taking might interact, you will be closely monitored by your doctor. Your doctor or pharmacist should explain the possible side-effects of your TB treatment and you will be monitored to see if you develop any. It also makes good sense to tell your doctor about any symptoms of side-effects that you experience as it is often possible to do something about them.

• Rifampicin. An anti-mycobacterial drug that is included in standard anti-TB combinations.
• Isoniazid. An antibiotic drug that, in combination with other drugs, is a standard treatment for TB. It is also sometimes used by itself as TB prophylaxis.
• Pyrazinamide. A first-line drug for the treatment of TB in combination with other drugs.
• Ethambutol. An anti-mycobacterial antibiotic which, in combination with other drugs is used as part of standard treatment TB.
• Clarithromycin. This drug is an antibiotic used for the treatment of the AIDS-defining illness MAI, but is also sometimes used to treat TB.
• Dapsone. An antibiotic used to treat the AIDS-defining illnesses PCP and MAI, which is also occasionally used to treat TB, particularly drug-resistant TB.
• Ofloxacin. Used to treat resistant TB.
• Rifabutin. This drug is used against the AIDS-defining illness MAI and is sometimes used as an alternative to rifampicin in anti-TB combinations.
• Streptomycin. The first effective anti-TB drug. It is now rarely used except in cases of multidrug-resistant TB. Administered by injection.
• Combinations pills . To help reduce the number of pills you need to take, some anti-TB drugs are available combined together in a single tablet. The following are available in the UK: Rifater (contains rifampicin, pyrazinamide and isoniazid), Rifinah (contains rifampicin and isoniazid) and Rimactazid (contains rifampicin and isoniazid).

In the UK, the TB treatment of choice is a combination of four antibiotics that work against TB. The treatment is taken for at least six months. For the first two months, four anti-TB drugs are used. These are isoniazid, rifampicin, pyrazinamide and ethambutol.

Treatment with two drugs, normally isoniazid and rifampicin, continues for a further four months. Everybody taking isoniazid should also take a vitamin supplement called pyridoxine to stop a painful side-effect involving nerve damage in the lower legs and feet (and sometimes the hands) developing.

If the TB is in other places besides the lungs, treatment may be needed for longer, especially if the TB is in the brain, or if there is TB meningitis.

It is normal to take all the drugs as tablets, once daily. Some drugs are combined into a single tablet to make them easier to take.

As TB comes under control, normally after a week or two of treatment, you will feel a lot better. If you have infectious TB you will stop being able to pass on the disease to others after this time, as long as you take anti-TB medication.

However, it is vital to go on and complete the full course of TB treatment. Failure to do this can cause the TB to come back, or drug resistance to emerge. If you would like more information on why taking medicines properly is important and some tips on things that might help you to take your medicines correctly read the NAM booklet in this series called Adherence.

Because of the importance of taking TB treatment correctly, both for your health and to avoid strains of TB developing which are resistant to anti-TB drugs, it might be recommended that a healthcare worker visits you at home every day to make sure that you take your medication. This is called Directly Observed Therapy (DOT for short), and it is standard practice in some countries. It is used in some circumstances in the UK, such as where someone has multidrug-resistant TB (see Drug resistant TB) or when a patient has problems with adherence.

Treating TB and HIV at the same time can be difficult. There can be interactions between some of the medicines used, and it can also mean taking a lot of pills. This can be an issue for people who have just been diagnosed with TB and HIV, those who have had HIV for sometime before being diagnosed with TB, and people who are taking HIV treatment and develop TB.

There are interactions between some anti-HIV drugs and TB medication. Types of HIV treatment called protease inhibitors and non-nucleoside reverse transcriptase inhibitors (NNRTIs) interact with rifampicin, a key drug included in many anti-TB combinations.

Many doctors recommend either delaying HIV treatment until the TB has been controlled, or even stopping or changing anti-HIV medication if a person develops TB whilst taking it. Treatment for HIV and TB can be very complex and your doctor will discuss with you the treatment best suited to your circumstances.

If you have a low CD4 cell count, and start anti-HIV drugs immediately after starting your TB treatment, you may be at risk of developing what is called immune reconstitution syndrome. This is when your strengthening immune system is stimulated to attack TB again. This can make you very unwell and cause unpleasant symptoms, particularly fever and an enlargement of the lymph nodes.

The British HIV Association (BHIVA), the professional body for doctors treating people with HIV, recommends that TB should be treated first if your CD4 cell count is above 350.

If your CD4 cell count is between 100 and 350, your doctor may recommend that you start your anti-HIV drugs two months after starting your anti-TB drugs. If you have a very weak immune system, with a CD4 cell count below 100, BHIVA recommends that you start HIV treatment as soon as possible after starting TB drugs as the risk of side-effects, drug interactions, and immune reconstitution syndrome are outweighed by the risk of further HIV-related illness and even death if HIV treatment is delayed.

Your doctor should discuss these issues with you and explain why decisions on how to treat your TB and HIV have been made.

UK doctors make special recommendations for the treatment of TB in HIV-positive women who are pregnant or breastfeeding.

It is important that pregnant women with active TB take TB treatment. Women with latent TB are also recommended to take isoniazid treatment if it is thought that they have a reasonable risk of developing active TB.  The chance of TB being passed on to the baby is very small, but if the woman is not treated for TB, there is an increased chance of early labour.

TB treatment in pregnant women should consist of four drugs – rifampicin, isoniazid, pyrazinamide and ethambutol for the first two months and then two drugs - rifampicin and isoniazid - for a further seven months. Pyridoxine (vitamin B-6) should also be taken to prevent isoniazid causing nerve damage.

If you are pregnant, it will be recommended that you take HIV treatment to protect your baby from being infected with HIV in the womb or during birth. The exact type of treatment will depend on your health and when your HIV was diagnosed. Because of the risk of an interaction between some anti-TB drugs and some anti-HIV medicines, it is extremely important that the doctors providing antenatal care and TB treatment are very knowledgeable about HIV and TB and work very closely together.

Because of the risk of passing on HIV, it is recommended that HIV-positive women in the UK should not breastfeed.

For more information on HIV and pregnancy and mother-to-child transmission of HIV see the booklets in this series, HIV and women and HIV and children.

Don’t be afraid to ask for support - having a baby is a life-changing experience in itself and if you have only just found out that you have HIV or TB, then you may have lots of questions, or may need extra support from family, friends, doctors, nurses and midwives and from other advice and support workers or other people living with HIV.  There is information and support available to you - if you are not sure where to go, then you could talk to someone at your clinic or call a helpline such as THT Direct (0845 12 21 200) or Positively Women (020 7713 0222).

Many anti-HIV drugs and anti-TB drugs can work well and safely together. However, as mentioned above, there can be interactions. It is not recommended to use certain anti-TB and anti-HIV drugs together and sometimes it is necessary to adjust the dose of one or the other.

The anti-TB drug rifampicin can cause large reductions in the amount of protease inhibitors (one of the types of anti-HIV drugs) in the blood, even if they are ‘boosted’ by ritonavir, making them ineffective and increasing the chance that resistance to anti-HIV drugs will develop. Because of this, rifampicin should not be used with many of the protease inhibitors. Rifampicin can be used with the commonly-prescribed NNRTI efavirenz (Sustiva, also in the combination pill Atripla).

Another anti-TB drug, rifabutin can also interact with protease inhibitors, causing the amount of antiretrovirals in the bloodstream to fall and the amount of rifabutin to increase. If taken with efavirenz, the amount of rifabutin in the blood can fall.

Because of these interactions it is very important that your doctor is skilled in the treatment of both TB and HIV.

If you are concerned about your treatment, or have any questions, ask your doctor or someone else involved in your care, to spend some time explaining your treatment to you.

Some people taking HIV treatment and who are also taking isoniazid or rifampicin may develop hepatitis (inflammation of the liver). Your doctor should do regular blood tests to check on the health of your liver as part of your care.

Isoniazid can cause painful nerve damage called peripheral neuropathy, and it is recommended that it is used with extreme caution if given at the same time as d4T or ddI, which also cause this side-effect. Taking a daily dose of vitamin B-6 (pyridoxine) can help prevent isonaizid causing peripheral neuropathy, but does not prevent peripheral neuropathy caused by some anti-HIV drugs.