13. The effects of high-dose calcitriol and ketoconazole on the developing human fetus are unknown. For this reason and because these agents as well are known to be teratogenic, men must agree to use adequate contraception (hormonal or barrier method of birth control; abstinence) prior to study entry and for the duration of study participation. Should a woman become pregnant or suspect she is pregnant while her partner is participating in this study, she should inform the treating physician immediately.