To further comply with the drug amendments of 1962 the FDA contracted in 1966 with the National Academy of Sciences/National Research Council to study drugs approved between 1938 and 1962 from the standpoint of efficacy. The Drug Efficacy Study Implementation (DESI) evaluated over 3000 separate products and over 16,000 therapeutic claims. The last NAS/NRC report was submitted in 1969, but the contract was extended through 1973 to cover ongoing issues. The initial agency review of the NAS/NRC reports by the task force was completed in November 1970. One of the early effects of the DESI study was the development of the Abbreviated New Drug Application (ANDA). ANDAs were accepted for reviewed products that required changes in existing labeling to be in compliance. In September 1981 final regulatory action had been taken on 90% of all DESI products. By 1984, final action had been completed on 3,443 products; of these, 2,225 were found to be effective, 1,051 were found not effective, and 167 were pending.

Among the products that came under intense scrutiny through DESI were preparations with multiple antiinfective ingredients, such as this one.