How To Take Levothyroxine When You Take Other Medications

In our latest question and answer, that pharmacist discusses options of how to take levothyroxine when you take multiple other medications.

Apr 08, 2018

Stacy asked

I take levothyroxine 25mcg, doxycycline hyclate 50 mg (for dry eyes/meibomian gland dysfunction), and fluoxetine (Prozac) 20 mg everydayI know the levothyroxine needs to be taken on an empty stomach. But can I take all three of these pills, with water, at the same time as each other? Also, is it ok to have a glass of milk about an hour after I take these three drugs?

Answer

While there are no major drug interactions between levothyroxine, doxycycline hyclate and fluoxetine, these medications should not be taken at the same time.

When taking levothyroxine, be sure to take it alone, on an empty stomach, and with a full glass of water for best absorption. Drinking a glass of milk an hour or so after taking levothyroxine is acceptable.

Proper Levothyroxine Administration

Levothyroxine is a synthetic version of thyroxine, which is a natural hormone produced by the thyroid gland. Levothyroxine is intended to be used as replacement therapy for patients with an under-active thyroid gland, commonly known as hypothyroidism.

Adequate levels of thyroxine are needed in the blood to maintain physical and mental health. Since certain drugs and foods can affect how levothyroxine is absorbed, it is recommended that these medications and foods be spaced out from the time of administration.  Absorption of levothyroxine occurs in the gastrointestinal (GI) tract, and thus it is best to take alone and while fasting for best absorption.

Medications and food supplements that have been found to greatly affect the absorption of levothyroxine. They include:

  • Antacids
  • Iron
  • Calcium supplements

If an individual is taking any of the above products, it is advised that they space administration of them by at least four hours after taking levothyroxine.

Since food can also interfere with how the levothyroxine is absorbed, it is recommended to wait 30 to 60 minutes before eating a meal after taking levothyroxine. In addition, it is generally recommended to take other medications, such as Prozac from, levothyroxine by at least 30 to 60 minutes.

If levothyroxine is taken with food or other medication, absorption can decrease. This could potentially lead to symptoms of hypothyroidism such as:

  • Lethargy
  • Feeling of cold
  • Weight gain

Summary

  • Despite no major interactions between the medications that you are currently taking, it is important that you take levothyroxine alone and on an empty stomach with a full glass of water for best absorption. 

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