Complete abstinence from intercourse from 2 weeks prior to administration of the investigational products, throughout the study, and for at least 2 weeks after discontinuation of all study medications Double barrier method (male condom/spermicide, male condom/diaphragm, diaphragm/spermicide). Hormonal contraception will not be considered adequate for inclusion into this study Any intrauterine device (IUD) with published data showing that the expected failure rate is <1% per year.