- The various drugs used are: Isoniazid (H), Rifampicin (R), Pyrazinamide (P), Ethambutol (E), Streptomycin (S) and Thiacetazone (T). These are also called the first line or essential anti-TB drugs, which are used in patients, who are diagnosed as having TB for the first time. They can also be used in patients with relapse and treatment failure cases.
- Second line drugs such as Kanamycin, Cycloserine, Ethionamide, PAS, Ciprofloxacin, Ofloxacin etc. are expensive, not very effective and more likely to cause severe side-effects. These drugs are used in Multi Drug Resistant TB (MDR-TB).
- The anti-TB drugs have been divided into two groups according to their mode of action :
- Bactericidal drugs (which kill the TB germs) include Isoniazid, Rifampicin, Pyrazinamide and Streptomycin.
- Bacteriostatic drugs (which prevent the growth of TB germs) include Ethambutol and Thiacetazone.
- Regimens recommended for Tuberculosis – The treatment of tuberculosis is divided into two phases :
o Initial Intensive phase – In this phase, a combination of three/four/five drugs are used for a period of 2 – 3 months. Rapid killing of TB germs occurs with patients becoming non-infectious within 3 – 6 weeks. With treatment, the symptoms improve and the sputum smear becomes negative (if positive initially). The drugs used in this phase are Isoniazid (H), Rifampicin (R), Pyrazinamide (P), Ethambutol (E), Streptomycin (S).
o Continuation phase – Here, fewer drugs are used for a longer time (4 – 6 months) to eliminate the remaining (last few) TB germs and prevent any relapse. The drugs used in this phase are Isoniazid, Rifampicin, Ethambutol.
Standard code for treatment regimen –
o 2 RHZE / 4RH – indicates an initial intensive phase of two months with four drugs and a continuation phase of four months using two drugs.
o 2 (RHZE)3 / 4 (RH)3 – This treatment regimen involves, intermittent use (thrice weekly) of drugs for the same duration.
o There are a number of other regimens approved by WHO, which can be prescribed by your physician (for they can vary from these above mentioned regimens).
o Medications are altered by the physician based on sputum smear results and the response to the treatment. The exact plan of treatment must be determined by your physician.
- Fixed Dose Combinations (FDCs): WHO and the International Union against Tuberculosis and Lung Disease (IUATLD) advocate the replacement of single-drug preparations by FDC tablets as the primary treatment for tuberculosis.
Advantages of FDCs over therapy with individual drugs:
- Improves patient compliance to the medication as less number of tablets are to be taken.
- It simplifies the treatment approach by delivering the required drugs in appropriate dosage, as all the necessary medications are combined in a single tablet.
- Helps in preventing the development of drug-resistant tuberculosis which can happen if individual drugs are used separately and patient misses any one of them.
- Upon starting treatment, most patients start feeling well within a fortnight (the fever decreases and the appetite improves).
- If treatment is taken regularly, most of the TB germs in the patient’s body are killed and the sputum test at the end of two months of treatment turns negative. The patient should continue the treatment till he is advised to stop it (by the treating physician), in order to avoid any relapse or development of drug resistant TB (MDR-TB) later on in his life.
- The common side-effects of drugs encountered during the treatment of TB are grouped as minor and major reactions.
- Minor side-effects include :
o Anorexia, nausea, vomiting
o Abdominal pain (gastritis)
o Tingling sensation in hands and feet
o Dark (reddish) coloured urine / other body fluids (sweat, tears)
o Joint pains (gout)
- Major side-effects include :
o Skin rashes
o Mental confusion / psychosis
o Blindness (decrease in vision)
o Kidney failure
- Common individual drug side-effects include:
o Isoniazid – jaundice, tingling / burning sensation of hands and feet, skin rash
o Rifamipicin – jaundice, skin rash
o Ethambutol – skin rash, blindness (hence avoided in small children)
o Pyrazinamide – jaundice, joint pains, skin rash
o Streptomycin – deafness, dizziness, kidney failure (avoided in a HIV / pregnant patient)
o Thiacetazone – skin rash, jaundice (not to be given to a HIV patient)
- DO NOT BE ALARMED IF YOU FIND THAT YOUR URINE IS REDDISH IN COLOUR AFTER TAKING RIFAMPICIN.
- Management of common side-effects of drugs encountered during treatment:
- Loss of appetite with nausea and vomiting
It is usually managed with antacids, anti-ulcer and anti-emetic drugs. If symptoms do not subside, the patient is then asked to take the drugs after breakfast, instead of taking them empty stomach. If symptoms still do not resolve, then liver function test (for jaundice) can be recommended. If liver function test is deranged, STOP all anti-TB drugs. Jaundice usually resolves in 7-10 days. Then the treatment can be started again, usually with the same drugs. One should consult a physician for all complaints of nausea and vomiting due to anti-TB drugs.
- Skin rashes and itching
Few patients complain of itching and rashes while on treatment. These rashes usually resolve spontaneously and occasionally with some anti-allergic treatment. If the rash does not disappear and is accompanied by fever, eye involvement and an extensive peeling of skin, then it may be a serious condition called the Steven Johnson Syndrome (usually occurs due to thiacetazone). One should consult a physician if any rash develops while taking any anti-TB treatment.
- Tingling sensation in limbs
Most commonly seen with isoniazid therapy. It is mostly seen in individuals who are malnourished, alcoholics, have uncontrolled diabetics or are elderly. Easily treated with co-administration of Pyridoxine (Vitamin B6). One should consult a physician on experiencing any tingling sensation in hands or legs.
4. Joint Pains
Usually seen due to pyrazinamide therapy. Easily managed with Aspirin or other analgesics as prescribed by your physician.
5. Eye Problems
These are usually encountered while treating patients with Ethambutol. One should consult a physician on experiencing decreased vision and disturbance in colour perception. Discontinuing Ethambutol is recommended.