The NFL and its union are discussing strengthening their drug program to keep pace with the increase in the number of performance-enhancing substances and the efficiency of masking agents. Commissioner Roger Goodell, in his first news conference since taking over for Paul Tagliabue last Friday, said Wednesday he has been discussing the problem with Gene Upshaw, the head of the NFL Players Association. Among the topics discussed were increasing the number of tests and perhaps the number of substances tested.