Before taking estramustine, tell your doctor or pharmacist if you are allergic to it; or to estradiol or other estrogens; or to nitrogen mustard (such as mechlorethamine); or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: blood clots (such as in the legs, eyes, lungs), bone disease (such as bone metastases, high calcium levels), high cholesterol or triglyceride (blood fat) levels, depression, diabetes, severe headaches (such as migraine), heart disease (such as angina, heart attack, heart failure), high blood pressure, kidney disease, liver disease, seizure, long periods of sitting or lying down (for example, due to being bedridden), stroke, thyroid problems.

Do not smoke cigarettes or use tobacco. Estrogens combined with smoking further increase your risk for stroke, blood clots, high blood pressure, and heart attacks.

If you will be having surgery or will be confined to a chair or bed for a long time (such as on a long plane flight), notify your doctor beforehand. Special precautions may need to be taken in these circumstances while you are taking this drug because of the increased risk for blood clots.

If you have diabetes, estramustine may affect your blood sugar. Check your blood sugar regularly as directed and share the results with your doctor.

If you are nearsighted or wear contact lenses, you may develop vision problems or trouble wearing your contact lenses. Contact your eye doctor if these problems occur.

This medication may cause blotchy, dark areas on your face and skin (melasma). Sunlight may worsen this effect. Limit your time in the sun. Avoid tanning booths and sunlamps. Use sunscreen and wear protective clothing when outdoors.

This medication may affect the production of sperm. Use a reliable form of birth control while on this medication. Consult your doctor.

This medication is not usually used in women. It is unlikely to be used during pregnancy or breastfeeding. Consult your doctor if you have any questions about this medication.