Before taking tamoxifen, tell your doctor or pharmacist if you are allergic to it; 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 deep vein thrombosis, pulmonary embolism, stroke), certain heart problems (fast/slow/irregular heartbeat, QT prolongation in the EKG), high cholesterol/triglycerides, limited or no ability to walk (immobility), diabetes, high blood pressure, smoking, cataracts, liver disease.

Before having surgery (especially breast reconstruction), tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

Tell your doctor if you are pregnant or plan to become pregnant. You should not become pregnant while using tamoxifen. Tamoxifen may harm an unborn baby. Women using this medication should ask about reliable non-hormonal forms of birth control (such as condoms, diaphragms with spermicide) during treatment and for 2 months after the last dose. Men using this medication should ask about reliable forms of birth control during treatment and for 6 months after the last dose. If you or your partner becomes pregnant, talk to your doctor right away about the risks and benefits of this medication.

It is unknown if this medication passes into breast milk. Because of the possible risk to the infant, breastfeeding is not recommended while using this medication and for 3 months after the last dose. Consult your doctor before breastfeeding.