Blood pressure, antipsychotic and certain antidepressant medications are commonly prescribed drugs that can interfere with the sexual response. Birth control pills change your hormone levels and can cause a decrease in desire or vaginal dryness.Anti-estrogen hormonal medications for breast cancer or drugs used to prevent recurrence of breast cancer, such as tamoxifen (Nolvadex), also can produce vaginal dryness and difficulties with vaginal penetration. Chemotherapy for cancer can impair many bodily functions and responses, including sexual desire and arousal. Anti-convulsants for seizures also can cause sexual problems.