How Do Antitubercular Agents Work?

Antitubercular agents are a class of drugs used to treat tuberculosis (TB). TB is a contagious disease caused by bacteria called ‘Mycobacterium tuberculosis’ which usually affects the lungs but can also affect many other organ systems. Active TB treatment involves giving two to four drugs simultaneously for six to nine months.

There are two forms of TB, namely:

• Latent TB: germs are present in the body; however, there are no symptoms as the immune system is actively working to fight against it. It is a noncontagious state.
• Active TB: germs multiply and symptoms are developed. It is a contagious state.

Signs and symptoms of active TB disease include:

• A cough that lasts more than three weeks
• Chest pain
• Coughing up blood
• Feeling tired all the time
• Night sweats
• Chills
• Fever
• Loss of appetite
• Weight loss

Antitubercular drugs are used in different combinations in different circumstances; some of the first-line anti-TB drugs are used only for the treatment of new patients who are very unlikely to have resistance to any of the TB drugs, and other second-line drugs are used only for the treatment of drug-resistant TB.

Antitubercular drugs are prescription-only medicines and are administered via oral and intravenous routes.

Antitubercular agents work in the following ways:

• Antitubercular agents work by stopping the growth of the bacteria that causes TB (Mycobacterium tuberculosis).
• They act by reversibly inhibiting DNA-dependent RNA polymerase, which further inhibits bacterial protein synthesis and transcription.
• They inhibit the enzyme arabinosyltransferases and thus prevent the biosynthesis of the mycobacterial cell wall.
• TB bacteria die very slowly, and so, the drugs must be taken for quite a few months until all bacteria are dead.

Antitubercular agents are used in conditions such as:

• TB
• Multidrug-resistant pulmonary TB (a serious infection that affects the lungs and other parts of the body and cannot be treated with other medications that are usually used to treat the condition)
• Gaucher's disease (a rare, inherited metabolic disorder in which deficiency of the enzyme glucocerebrosidase results in the accumulation of harmful quantities of certain fats [lipids] within the bone marrow, spleen, and liver)
• Urinary tract infection
• Mycobacterium avium complex prophylaxis (a group of mycobacteria comprising Mycobacterium intracellulare and Mycobacterium avium)
• TB treatment for human immunodeficiency virus exposed/infected

Common side effects include:

• Diarrhea
• Nausea
• Vomiting
• Abdominal pain
• Anorexia (lack or loss of appetite)
• Headache
• Malaise (a general feeling of discomfort, illness, or unease)
• Muscle/joint pain
• Upset stomach
• Heartburn
• Metallic taste in the mouth
• Other rare side effects include:
• Dizziness (feeling faint, weak, or unsteady)
• Fever
• Rash
• Arthralgia (pain in one or more of your joints)
• Gout (a form of arthritis caused by excess uric acid in the bloodstream)
• Thrombocytopenia (low blood platelet counts)
• Liver function test abnormalities
• Optic neuritis (symptoms may include decreased acuity, color blindness, or visual defects)
• Slurred speech
• Mental/mood changes (such as confusion, unusual behavior)
• Signs of kidney problems (such as a change in the amount of urine)
• Coughing up blood
• Chest pain
• Liver disease
• Persistent nausea/vomiting
• Severe stomach/abdominal pain
• Yellowing of eyes/skin
• Dark-colored urine

Information contained herein is not intended to cover all possible side effects, precautions, warnings, drug interactions, allergic reactions, or adverse effects. Check with your doctor or pharmacist to make sure these drugs do not cause any harm when you take them along with other medicines. Never stop taking your medication and never change your dose or frequency without consulting your doctor.

Drug names include:

• Aminosalicylic acid
• Bedaquiline
• Capastat
• Capreomycin
• Clofazimine
• Cycloserine
• Ethambutol
• Ethionamide
• Isoniazid
• Lamprene
• Myambutol
• Mycobutin
• Paser
• Pretomanid
• Priftin
• Pyrazinamide
• Rifabutin
• Rifadin
• Rifamate
• Rifampin
• Rifampin/isoniazid
• Rifampin/isoniazid/pyrazinamide
• Rifapentine
• Rifater
• Rimactane
• Seromycin
• Sirturo
• Trecator