Johns Hopkins Hospital in Baltimore, one of the nation's leading medical research and treatment centers, has decided to postpone until fall a mandatory drug-testing policy for hospital physicians that has drawn opposition from medical school faculty and students.

"It has taken longer than expected to implement," said hospital spokeswoman Carol Pearson. Approved by hospital officials in February, the mandatory drug-testing plan was scheduled to begin last month.

Pearson said the first group of physicians to be screened for the use of alcohol, marijuana, cocaine, heroin, opiates, PCP and amphetamines is expected to start "closer to the fall" so hospital officials can iron out final details on testing and notification procedures.

The testing program, believed to be first in the country for a medical facility, has been assailed by the Johns Hopkins Medical School Council, a 42-member board of elected representatives from all departments in the school. In May, the council voted unanimously "to strongly oppose" the drug-testing policy, said Kenneth O. Johnson, chairman of the council's committee on drugs and substance abuse.

"Urinalysis is just not a dignified, caring way to deal with one another," said Johnson, a professor of neuroscience. Calling the policy "terrible and divisive," Johnson said, "If there was some evidence that there is a serious drug problem, then there might be a good reason for adopting it. But there is no such evidence."

Hospital officials said they approved the drug-testing program for the 1,500 staff physicians to set an example and promote a "drug-free environment." Pearson said doctors who test positive will be retested for accuracy and offered extensive rehabilitation treatment.