There are two main interim treatment outcomes that can occur during Drug-resistant TB (DR-TB) treatment. These are:

Bacteriological Conversion: This occurs after bacteriological confirmation of TB in at least two consecutive cultures (applicable for DR-TB and Drug-sensitive (DS-TB)) or smears (applicable for DS-TB only), taken on different occasions, at least 7 days apart, are found to be negative.

Adverse Drug Reactions (ADRs) have been graded based on their severity. The figure below provides criteria for the assessment of the severity grade of ADRs.

Figure: Criteria for Severity Grade Assessment of ADRs

The World Health Organisation-Uppsala Monitoring Centre (WHO-UMC) system has been developed as a practical tool for the assessment of case reports. 

The table below lists the various causality categories and their assessment criteria that have been developed under this system.

Attribution definitions for causality assessment are divided into five categories and are as follows:

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• Not related​

Adverse Event (AE) that is not related to the use of the drug.​

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• Doubtful ​

AE for which an alternative explanation is more likely, e.g., concomitant drug(s), concomitant disease(s) or the relationship in time suggests that a causal relationship is unlikely.​

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There are three methods for reporting pharmacovigilance activities (see figure below).

Figure: Three Methods for Reporting Pharmacovigilance Activities

he potential adverse drug events that can occur when using drugs in the H mono/ poly DR-TB regimen are tabulated below:

Treatment with Isoniazid (H) mono/ poly Drug-resistant Tb (DR-TB) regimen needs special considerations in certain special situations.

Pregnancy and Lactation

Different conditions may demand the replacement of Isoniazid (H) mono/ poly Drug-resistant TB (DR-TB) and shorter oral Bedaquiline (Bdq)-containing Multidrug-resistant (MDR)/ Rifampicin-resistant (RR) -TB regimens.

Replacement Sequence of Drugs in H Mono/ Poly DR-TB Regimen

Drugs of the H mono/ poly DR-TB regimen will be replaced in case of:

Isoniazid (H) mono/ poly Drug-resistant TB (DR-TB) regimen has the following regimen, duration and dosage of drugs.

Regimen: (6 or 9) Lfx R E Z

Dosage

Pre-treatment evaluation for any TB patient must include a thorough clinical evaluation by a doctor with:

• History and physical examination
• Height/ weight check
• Random Blood Sugar (RBS) 
• Chest X-ray 
• HIV test

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No additional investigations (except the basic evaluations mentioned above) are required for Isoniazid (H) mono/ poly Drug-resistant TB (DR-TB) patients unless clinically indicated.