Drug Interaction Report

Before using conjugated estrogens, tell your doctor if you also use levothyroxine. You may need dose adjustments or extra monitoring to safely take both medications together. If you are already using conjugated estrogens and levothyroxine, your thyroid levels may need to be measured if your dose of conjugated estrogens is changed or stopped. You should notify your doctor if you have symptoms of low thyroid hormone levels such as tiredness, feeling cold, constipation, unexplained weight gain, depression, joint or muscle pain, thinning hair or hair loss, dry skin, hoarseness, and abnormal menstrual periods. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

The timing of meals relative to your oral levothyroxine dose can affect the absorption of the medication. Therefore, levothyroxine should be taken on a consistent schedule with regard to time of day and relation to meals to avoid large fluctuations in blood levels, which may alter its effects. In addition, absorption of levothyroxine may be decreased and/or delayed by foods such as soybean flour, cotton seed meal, walnuts, dietary fiber, calcium, calcium fortified juices and grapefruit or grapefruit juice. These foods should be avoided within several hours of dosing if possible. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

Using multivitamin with minerals together with levothyroxine may decrease the effects of levothyroxine. You should separate the administration of levothyroxine and multivitamin with minerals by at least 4 hours. If your doctor does prescribe these medications together, you may need a dose adjustment or special test to safely use both medications. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

Information for this minor interaction is available on the professional version.