Patients with hypertension should be monitored closely for increases in blood pressure if estrogens are administered. Estrogens can cause amenorrhea and interfere with the effects of bromocriptine. Concurrent use is not recommended. Estrogens can increase calcium absorption. In general, the interaction between calcium salts and estrogen is beneficial and is used to therapeutic advantage in postmenopausal women who have osteoporosis.
Estrogens can inhibit the metabolism of cyclosporine.
Estrogens should be avoided whenever possible in patients receiving cyclosporine. If this combination cannot be avoided, cyclosporine concentrations should be monitored closely after the addition of the estrogen until a new steady-state level is achieved. Estrogens have reportedly potentiated the anti-inflammatory effects of hydrocortisone and delayed the clearance of prednisolone. Studies involving other corticosteroids have failed to show an interaction. Estrogens may decrease corticosteroid metabolism secondary to enzyme inhibition, compete at metabolism sites, or alter the protein binding of corticosteroids.