Drug interactions between Alora and Synthroid
Results for the following 2 drugs: |
|
|---|---|
| Alora (estradiol) | |
| Synthroid (levothyroxine) | |
Interactions between your selected drugs
levothyroxine ⇔ estradiol
Applies to: Synthroid (levothyroxine) and Alora (estradiol)
MONITOR: Estrogens may increase serum thyrotropin concentration, which could be harmful in patients with thyroid cancer receiving thyroxine for thyrotropin suppression or increase dosage requirements in patients with hypothyroidism receiving thyroxine for replacement therapy. Estrogens are known to increase serum thyroid-binding globulin concentration in a dose-dependent manner. Consequently, there may be a reduction in unbound, or free, thyroxine available for hormone activity, which, in turn, leads to an increase in serum thyrotropin concentration. Normally, thyroxine secretion can increase to compensate for this effect, but patients with hypothyroidism lack the mechanism to adapt. Limited evidence suggests that transdermal estrogen therapy may not affect thyroid-binding globulin concentrations; however, more data are required to confirm that.
MANAGEMENT: In patients treated with thyroxine, serum thyrotropin should be measured approximately 12 weeks after estrogen therapy is initiated, changed or discontinued, and the thyroxine dosage adjusted accordingly. Patients should be advised to contact their physician if clinical manifestations of hypothyroidism occur, such as fatigue, cold intolerance, constipation, unexplained weight gain, depression, joint or muscle pain, thinning hair or hair loss, dry skin, hoarseness, and abnormal menstrual periods.
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