If a person is taking corticosteroids or immunosuppressants those drugs should be stopped before starting pembrolizumab because they may interfere with pembrolizumab; they can be used after pembrolizumab is started to deal with immune-related adverse effects [REF].
Women of child-bearing age should use contraception when taking pembrolizumab; it should not be administered to pregnant women because animal studies have shown that it can reduce tolerance to the fetus and increases the risk of miscarriage.