MDT: duration of treatment FAQ
What is the reason for shortening the duration of MDT to MB patients to 12 months?
The most important component of the MDT regimens is rifampicin. The majority of rifampicin-susceptible M. leprae are killed by few monthly doses of rifampicin. Recently it has been shown that the daily combination of dapsone and clofazimine is highly bactericidal. This combination is capable of eliminating any rifampicin-resistant mutants in an untreated MB leprosy patient within 3-6 months. Several studies have demonstrated that MB leprosy patients who received less than 24 monthly doses of MDT, responded as favourably as those who received 24 or more doses of MDT. Therefore, the 7th WHO Expert Committee considered that the duration of treatment of MB leprosy can be reduced to 12 months without compromising the efficacy of the MDT regimen.
Is there any problem foreseen in treating MB patients with a high bacteriological index (BI) with 12-month MDT regimen?
Multibacillary patients starting with a high BI may have a higher risk of developing reactions and nerve damage during the second year than those patients starting with a low bacterial index. Secondly, this group of patients starting with high bacteriological index are likely to show clearance of skin lesions more slowly and are likely to have a significant level of bacterial index at the end of 12 months compared with those starting with lower BI. While most of the high BI patients will continue to improve even after stopping of 12 months of treatment, some may not, and such patients not showing any improvement, with evidence of deterioration will need an additional 12 months of MDT for multibacillary leprosy.