President Reagan said yesterday that he and his wife, Nancy, will continue to crusade against drug abuse after he leaves office next January.

Reagan, who rarely has furnished a glimpse of what he plans to do after his second term ends, used his regular weekly radio address to urge more vigilance by Americans about the drug threat.

In so doing, he said that "Nancy and I are dedicated to working with you in the years ahead to

secure the gains we've made, and to keep our

country moving toward the goal of a drug-free America.

"Nancy, I know, has dedicated her life to this. Not just as first lady, but as parent and good citizen," he said in the address from the Oval Office. "Our commitment will not end when we leave Washington at the end of my term."

Reagan said both he and the first lady will attend the opening Monday of the White House Conference for a Drug-Free America. "It's a gathering of concerned citizens from every walk of life who are working with us to develop a national strategy to fight drug abuse in America," he said.

Despite the recent spate of drug-related murders and deaths among young people, Reagan expressed optimism about controlling the problem.

"A decade ago, drug abuse was ignored, and in some circles, was even glamorized," he said. "That complacent attitude has been replaced with vigorous and active involvement. Not only is the use of illegal drugs no longer accepted, but it is in many circles no longer tolerated."