Howard University's medical, dental and pharmacy schools, along with 20 other health professional schools, have been suspended from a federal student loan program because too many of their former students have failed to repay their loans.

The schools -- many of them predominately black or in urban areas -- were suspended from the Health Professions Student Loan (HPSL) Program because they failed to reduce their delinquency rate to 5 percent, or at least to cut it in half, since the government first threatened to suspend them from the program last June. At the end of last year, more than 40 percent of Howard medical students who had received the loans were delinquent, 33 percent of Howard dental students, and 55 percent of its pharmacy students.

The suspensions mean that the schools -- including divisions at Temple, Florida A&M, Rutgers and Wayne State universities -- may no longer make loans under the program, which provides direct loans exclusively to students pursuing health professions. Although they now rely more on the guaranteed student loan program, the HPSL program has helped thousands of health professional students -- many of them minorities and women -- since its creation two decades ago.

Howard officials could not be reached for comment. In the 1981-82 school year, 175 of its 496 medical school students received HPSL loans.

The suspensions are the latest in a series of Reagan administration efforts to step up collection of outstanding federal loans -- and tighten credit procedures in general. At the same time, the administration is proposing deep cuts in other college aid programs.

The tough new 5 percent delinquency standard for the health professional loans has been strongly opposed by some schools and by the American Association of Medical Colleges (AAMC), which see the requirement as being too strict, impossible to meet in a short time, and unfairly weighted against urban schools with large numbers of minority students.

When the HPSL program began in 1963, one of the government's goals was to increase the number of blacks, women and Hispanics in the health professions, with little concern about when the loans would be repaid. Now the government's most pressing concern has become the mounting federal deficit and attention has turned to collecting old debts.

William Dean, associate comptroller of Wayne State University, said his school has issued about 280 loans over the life of the program, and now has a delinquency rate of about 18.5 percent.

Most of that overdue money, he said, is because of 21 "problem cases," including one former pharmacy student who dropped out and is unemployed. "In a couple of other cases, we know the people are in prison," he said.

A spokesman in the Health and Human Services Department's Bureau of Health Professions, which administers the program, said that the bureau has specific guidelines for tracking debtors, and that schools are not held responsible for old debts once they show "due diligence."

In some cases, students are able to repay their loans and simply have ignored them. "Some of these are MDs who have been out of school, some of them for 15 years," said Dr. Maggie S. Wright of the State University of New York at Buffalo, whose medical, dental and pharmacy schools were suspended. "They're making good money and they're refusing to repay."

But, Wright said, "It's going to have a tremendous impact on our student population to lose these loans. It's harmful, particularly for the students who are already in the pipeline . . . . What do we do with a student who is in his second or third year? Tell him he has to drop out?"

Congress has not appropriated new money for the program for the past two years. Because the loan program is a revolving fund, schools are free to loan out any new money they collect. The suspended schools will have until June 30 to meet the 5 percent standard, and if they do not, they will be told to return all the HPSL money they have.