Interventions for Tuberculosis Control and Elimination 2002

Per cent culture positive
100
90
80
70
60
50
40
30
20
10
0
0 4 8 12 16 20 24 28 32 36 40
Week of treatment
Figure 45. Sputum culture conversion among patients treated with streptomycin
and para-aminosalicylic acid compared to streptomycin and isoniazid. 481
Kingdom, standard practice 497 following a trial by the British Medical
Research Council demonstrating faster conversion, fewer bacteriologic failures
and relapses. 496,498 The WHO considered it one of the major regimens
for low-income countries. 499 It took many years for experts of other
countries to be convinced of its importance, and that only after an international
comparative clinical trial. 500
Isoniazid plus ethambutol
Because of the frequency of side effects associated with para-aminosalicylic
acid, ethambutol appeared an attractive alternative. The US Public
Health Service trial 16 showed that sputum conversion was indistinguishable
in patients receiving, in addition to isoniazid, ethambutol in lieu of
para-aminosalicylic acid (figure 46), although there was a marked reduction
in the occurrence of adverse drug events. 484
Neither the US Public Health Service nor the British Medical Research
Council studied a 12-month regimen with isoniazid and ethambutol throughout,
supplemented by streptomycin in the intensive phase, although this regimen
has been widely used in low-income countries where thioacetazone
has been abandoned.
64
SM + PAS
SM + INH