Estramustine Disease Interactions

The risk of myocardial infarction and strokes, including those associated with estrogen use, may be increased in patients with hypertension. Moreover, estramustine may elevate blood pressure and worsen the hypertension, thus compounding the risk. Therapy with estramustine should be administered cautiously in patients with preexisting hypertension. Patients should be monitored for changes in cardiovascular status, and their antihypertensive regimen adjusted as necessary.

The use of estramustine, a combination of estradiol and nornitrogen mustard, is contraindicated in patients with active thrombotic or thromboembolic disorders, unless the tumor mass is thought to be the source of these conditions. Estrogens, particularly in high dosages, can increase the risk of thrombotic events, myocardial infarction, and strokes. Therapy with estramustine should be administered cautiously and only after careful consideration of risks and benefits in patients with cerebrovascular disease, coronary artery disease, or a history of thrombotic or thromboembolic disorders.

The use of estrogens is contraindicated in patients with undiagnosed, abnormal vaginal bleeding. Prolonged (> 1 year), unopposed estrogen use (i.e. estrogen without concomitant progestin therapy) has been associated with a significant, dose-related risk of endometrial carcinoma. The risk may be offset substantially by the addition of a progestin but may not be completely abolished. Prior to initiating estrogen therapy, appropriate diagnostic tests should be performed in patients with abnormal vaginal bleeding to rule out endometrial malignancy. The same applies if recurrent or persistent bleeding develops during estrogen therapy.

When treated with an estrogen, patients with breast cancer and bone metastases may develop severe hypercalcemia, in which case the drug should be stopped and measures be taken to reduce serum calcium levels.

Estrogens influence the metabolism of calcium and phosphorus. Intestinal absorption and retention of calcium are increased, which may occasionally result in hypercalcemia. Therapy with estrogens should be administered cautiously in patients with preexisting hypercalcemia, renal dysfunction, or metabolic bone diseases that are associated with hypercalcemia.

Estrogens are primarily metabolized by the liver. Patients with impaired hepatic function may be at increased risk for adverse effects associated with estrogen administration due to decreased drug clearance. Therapy with estrogens should be administered cautiously in patients with liver disease. In addition, clinicians should be aware that estrogen therapy may affect liver function tests. Increased sulfobromophthalein retention has been reported with the use of estrogen-containing oral contraceptives and may be expected with larger doses of estrogens.

Estrogens and progestogens may cause fluid retention, particularly when given in high dosages or for prolonged periods. Therapy with these agents should be administered cautiously in patients who have preexisting problems with excess fluid. In addition, patients with conditions that may be adversely affected by fluid accumulation, such as asthma, epilepsy, migraine, and cardiovascular or renal dysfunction, should be observed for exacerbation of their condition during estrogen and/or progestogen therapy.

Impaired glucose tolerance has been observed in some patients administered oral contraceptives and appears to be related primarily to the estrogen dose. However, progestogens can increase insulin secretion and produce insulin resistance to varying degrees, depending on the agent. Patients with diabetes mellitus should be monitored more closely during therapy with estrogens and/or progestogens, and adjustments made accordingly in their antidiabetic regimen.

When administering estrogen and/or progestogen therapy in patients with thyroid disorders, clinicians should be aware that these hormones may affect thyroid function tests. Changes have mostly been reported with the use of combination oral contraceptives. Specifically, thyroid-binding globulin (TBG) may be increased, resulting in elevated circulating total thyroid hormone, as measured by PBI (protein-bound iodine), T4 by column or radioimmunoassay, or T3 by radioimmunoassay. Free T3 resin uptake may be decreased. On the contrary, a decrease in TBG and, consequently, thyroxine concentration, has been reported by the manufacturers of the progestin-only (norethindrone) oral contraceptives.