Presidential employees will get letters next week telling them they face random drug tests in about 60 days, a step the American Civil Liberties Union said Friday likely would not have caught five alleged White House drug users.

Both President Reagan and his wife, Nancy, who has campaigned extensively against drug use, expressed dismay Thursday at the disclosure that two female National Security Council secretaries had resigned and three Secret Service officers were suspended during a drug probe."I think it's just evidence of what we've been saying. No one is exempt," Reagan said, adding, "This problem crosses all kinds of lines."

Mrs. Reagan, through her spokeswoman, Elaine Crispen, voiced disappointment and said, "Drugs are everywhere - in the workplace, movie industry, sports fields and college campuses. It's time everyone became involved and aware and intolerant of drug use."

Her husband, however, advocated treatment rather than intolerance for the White House employees implicated in the case.

Reagan said during brief comments to reporters that "if it's just a case of using" drugs rather than dealing, "I would like to see us do our best to get them into a drug treatment organization, and that they will agree to accept a cure."

ACLU lawyer Lauren Siegel said urine testing is a serious intrusion of privacy rights.

Neither White House spokesman Marlin Fitzwater nor Secret Service spokesman Bob Snow would identify the individuals involved or the substances allegedly used. Published and broadcast reports have said the probe focused on cocaine and marijuana use.