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Evidence Based Medicine Indian Pediatrics 2000;37: 1031-1033 |
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Intermittent Dosing of Anti-tubercular Drugs |
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This strategy is being implemented by the Government of India under the RNTCP (Revised National Tuberculosis Control Program)(3). However, so far nothing has been published in India about operationalized use of this strategy for treatment of children under program conditions. A practical difficulty elaborated is that children are mostly sputum smear negative and hence do not qualify for inclusion. this is indeed true, because most children are unable to produce sputum. Though this problem can be partly circumvented by using smears of gastric lavage(4) or induced sputum(5), the therapeutic decisions for childhood tuberculosis are mostly made in the absence of bacteriological proof. Tuberculosis in children is diagnosed on the basis of a combination of clinical criteria, tuberculin positivity and radiological find-ings(6). Definite evidence of disease on histo-pathology or bacteriology can be obtained only in a minority of cases. However, it is well realized that children with tuberculosis are a reserve pool who, if untreated, will usually either succumb to this infection or become adults capable of transmitting infection. The treatment of children with tuberculosis should therefore be a priority. This will necessitate modification of criteria for children to be selected for DOTS under RNTCP. The Indian Academy of Pediatrics had published consensus guidelines for management of tuberculosis in children in 1997(7). These guidelines had given protocols for treating tuberculosis in children on daily basis. However modification will have to be made in light of the new (actually old, being rediscovered) informa-tion being available. Short course chemotherapy has been well documented to be effective in tuberculosis(8,9). It has been well documented that intermittent therapy given twice or thrice weekly is as effective as daily therapy. In some experimental studies it has been shown to be even more effective than daily therapy(10). Intermittent therapy is very well tolerated in children and use of this mode brings down the cost of therapy by decreasing the number of visits to be made by the community health worker and by decreasing the total amount of drugs being given to the patients. The doses recommended by intermittent therapy are only marginally high for anti tubercular drugs except Isoniazid which is two to three times the dose given in daily therapy and does not add substantially to the total cost. Rifampicin which is an essential component of all short course regimens is given in the same dose. Intermittent drug treatment delivered in the community has the potential to improve adherence to treatment. Several cohort studies conducted in Africa, East Asia, the Indian subcontinent and Poland have suggested that equally high cure rates can be achieved with Rifampicin containing regimens which com- prise an initial phase of daily treatment (ustually two months) followed by intermittent treatment for a further 4 to 6 months (referred to as Partial Intermittent Shortcourse Treatment). However, a possibility for which one has to be concerned in intermittent regimens, is the occurrence of a relapse of the disease. A meta-analysis published in the most recent issue of the Cochrane Library, a data base of high quality systematic reviews has addressed the issue of fully intermittent dosing of the durgs for tuberculosis(11). The conclusions of this review are mainly based on data from adult studies due to strict adherence to inclusion criteria of type of participants being previously treated or untreated adult patients with a positive growth on culture of Mycobacterium tuber-culosis, or one or more sputum smear positive for mycobacteria by direct or indirect microscopy. This has led to exclusion of pediatric studies from this review. Hence, the results of this systematic review are based on one trial involving 399 patients in which antitubercular treatment was given three times a week(12). There was no difference in the cure rate (198 out of 199 people in the intermittent group compared to all 200 in the daily group), but 5 patients relapsed in the group receiving intermittent treatment compared to one receiving daily treatment. According to the reviewers there was not enough evidence to assess the equivalence of effect between fully intermittent and similar daily regimen containing Rifampicin for short course treatment of tuberculosis. More patients had relapsed in the fully intermittent group but the size of the study had been insufficient to show if this was a true effect or had arisen by chance. There was no indication of the differ-ential adverse reactions or the development of in vitro drug resistance during chemotherapy. However, the reviewers state that several methodological deficiencies make these conclusions only tentative. The Indian study(9) dealing with children (which has been excluded from the review) had compared fully intermittent regimen given twice weekly (52 doses) with a daily followed by intermittent treatment regimen (94 doses) for shortcourse chemotherapy of children. Overall efficacy of both the regimens was more than 95% in 27 children with lymphatic, 43 with pulmonary and six with disseminated tuber-culosis. The drugs in this study were administered in the clinic for the intermittent regimen and the others were given as a weekly supply of the drugs. Another study done in India(13) had studied the efficacy of 6 months intermittent regimen with a 9 months daily regimen. A total of 137 children with pulmonary tuberculosis were treated with one of the two regimens. The first regimen had Isoniazid and Rifampicin administered daily for 9 months. The drugs were collected once a week and administered at home. The second regimen had Isoniazid, Rifampicin and Pyrizinamide given thrice a week for the first two months followed by Isoniazid and Rifampicin twice a week for next 4 months with all doses fully supervised. The response to treatment was similar for both the regimens. The treatment had to be continued further for three months in 9 patients (5 in regimen I and 4 in regimen II) due to presence of residual lesions. The overall conclusion can be that intermittent therapy has been found to be effective in treatment of children with tuberculosis in Indian conditions. Currently, four drugs are recommended to be given in the intensive phase because of high prevalence of INH resistance. Since this therapy leads to significant economic benefits and facilitates the programme implementation, it should be adopted for treatment of tuberculosis in children under direct supervision. Meenu Singh,
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