The cost of antituberculous drug regimens

The relative costs of several highly effective short-course regimens have been compared for a developing and a developed country both for 1976 and 1978, with particular reference to the proportion of the total cost due to individual drugs. A convenient method of calculating costs for any individual country is provided. Of isoniazid, pyrazinamide, and rifampin, the 3 most important drugs in short-course chemotherapy, the cost and duration of the latter two have a major effect on the total cost. A decrease in the duration of a regimen from 9 to 6 months may decrease therapeutic effectiveness by as little as 5% or as much as 20%; the decrease in cost is often not proportional, because it depends on the drugs used in the continuation phase. The duration of pyrazinamide therapy has a considerable influence on cost, but the benefit of giving it beyond 2 months now needs to be re-evaluated. Factors that influence the choice of regimens are discussed. The importance of quality of the drugs, including purity and bioavailability, is stressed.