5.5 Treatment category for all TB patients

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New TB patients:

  • All Drug Sensitive TB (DS TB) patients, whether bacteriologically confirmed or clinically diagnosed, will receive the standard Treatment Regimen comprising of 4 drugs – HRZE - for the initial 2 months (Intensive Phase) and 2 drugs – HR - for the remaining 4 months (Continuation Phase).
  • The Treatment may be extended in certain forms of EP-TB like CNS TB, Skeletal TB, Disseminated TB etc. based on clinical decision of the treating physician on a case-to-case basis.

Previously Treated TB patients:

  • All cases will be subjected to drug susceptibility testing (DST) and the regimen decided based on the DST results.
  • If the DST results show that the patient is susceptible to both rifampicin and isoniazid, all bacteriologically confirmed previously treated pulmonary as well as extra-pulmonary TB patients will be given Cat.1 regimen i.e., 2EHRZ/4HR. The treatment may be extended in certain forms of EP-TB like CNS TB, Skeletal TB, Disseminated TB etc. based on clinical decision of the treating physician on a case-to-case basis.
  • All clinically diagnosed pulmonary TB cases with a history of previous treatment (PT Cases) will be given a 4-drug regimen for 6 months (6HRZE).
  • Patients in whom DST shows Rifampicin-susceptible but Isoniazid-resistant TB (Hr-TB) or INH DST result not available/not done, are given a 5-drug regimen for 6 months [6 (H)REZ- Lfx].
  • Patients with additional resistance patterns need to be managed accordingly.

5.6.1 Treatment phases

Treatment of drug-susceptible tuberculosis comprises of two phases:

  • The intensive phase (IP): This is administered daily for the initial two months (4FDC) of treatment. The objective of combining four drugs in the intensive phase (IP) is to achieve rapid killing of actively multiplying bacillary population. This phase will eliminate naturally occurring drug resistant mutants and prevent the further emergence of drug resistant mutants. The infectious patients quickly become non-infectious (within approximately two weeks of treatment initiation).
  • The continuation phase (CP): This is administered for four months (2FDC) and is essential to eliminate the remaining bacterial population (mainly persisters) which are largely responsible for relapses. In some special cases, the CP can be extended beyond 4 months (described above). The drugs are administered daily for the rest of the treatment duration according to the category.

Previously treated (PT) patients, eligible for retreatment, should be referred for a rapid molecular test or drug susceptibility testing to determine the resistance status to at least rifampicin, and also preferably isoniazid.

If R is sensitive but resistance to H is detected (Hr-TB)/ H DST unknown, then the patient is initiated on a 6-month regimen of 5 drugs [6 (H) REZ- Lfx].

If rifampicin resistance is detected, an MDR-TB regimen should be prescribed according to recent drug resistant TB treatment guidelines.

Standardized treatment regimen for each diagnostic category (adults)

* Treatment for certain EP TB may be prolonged till 12 months if non-resolving lymph nodes at 6 months; 12 months in case of CNS, TB meningitis, bone TB etc.

 

5.6.2 Fixed-dose combinations (FDCs)

In the management of TB patients with first line drugs, fixed-dose combination (FDCs) of anti-TB drugs are recommended over individual drugs. Fixed Dose Combinations refer to products containing two or more active ingredients in fixed doses, used for a particular indication(s).

Tablets of fixed-dose drug combinations have several advantages compared to individual drugs:

Advantages

  • Prescription errors are likely to be less frequent because dosage recommendations are more straightforward and adjustment of dosage according to patient weight is easier.
  • With less number of tablets to ingest, FDCs are more patient friendly and helps improve treatment adherence.
  • It prevents concealed irregularity as, in the absence of DOT, the patient cannot be selective in the choice of drugs to ingest.
  • Drug resistance is less likely to occur because mono therapy is avoided.
  • It helps simplify drug management.

Disadvantages

  • Risk of over dosage or under dosage (sub therapeutic blood levels) of all drugs occurring if number of tablets prescribed or taken is more or less than the treatment guidelines.
  • Health care workers may be tempted to evade Directly Observed Therapy, erroneously believing that adherence is automatically guaranteed.
  • Poor rifampicin bioavailability is a problem with low quality FDCs. Quality assurance is therefore essential.
  • Using FDCs does not obviate the need for individual drugs for a minority of patients who develop drug toxicity.

FDC tablets are composed as follows

  • 4 FDC: isoniazid 75 mg + rifampicin 150 mg + pyrazinamide 400 mg + ethambutol 275 mg
  • 2 FDC: isoniazid 75 mg + rifampicin 150 mg

The use of fixed-dose combination tablets is recommended over separate drug formulations in treatment of patients with drug-susceptible TB.

5.6.3 Drug dosages and frequency

  • Treatment dosages are based on weight bands.
  • Dosage should be appropriately modified if the patient changes to a new weight band during the course of treatment.
  • Drugs should be given daily. Intensive phase is for 2 months (60 doses).
  • Intensive phase is stopped after the patient completes 60 doses. Intensive phase should not be extended beyond 60 doses for any reason.
  • Continuation phase is daily for 4 months (120 dose).
  • Continuation phase is stopped after the patient completes 120 doses. Continuation phase should not be extended except for certain severe forms of EPTB (explained earlier).