Dosage and duration of therapy with Delatestryl depends on the age, sex, diagnosis, patient's response to treatment, and appearance of adverse effects. Delatestryl may interact with blood thinners, or corticosteroids. Tell your doctor all medications and supplements you use. Delatestryl must not be used during pregnancy. It may harm a fetus. It is recommended that women use 2 forms of birth control (., condoms and birth control pills) while using this medication; consult your doctor. It is unknown if this drug passes into breast milk. It may affect milk production and it may harm a nursing infant. Breastfeeding while using this drug is not recommended.