What’s Interfering With Your Thyroid Medication?

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If you are taking thyroid medication, you probably remember the important things like don’t take it with coffee, take an hour before breakfast, take it at the same time each day, and never miss a dose. These are very important medication instructions to follow, however, there is more to the story when taking these medications that you may not be aware of.

Many medications, supplements, and foods are important to avoid or not consume within three to six hours of taking your thyroid medication. These interfere with the the body’s ability to absorb and utilize thyroid medication effectively. When an interference of absorption happens, serious things can occur. You may become under medicated or even over medicated depending on the substance causing the interference. So, which substances cause an absorption issue?


Some medications decrease the absorption of thyroid medication while others increase it. While many of these other medications are needed, there are time guidelines to follow.

Antibiotics: Ciprofloxacin (Cipro, Cephalexin) or quinolone antibiotics (Levaquin, Maxaquin, Floxin) interfere with the effectiveness of your thyroid medication by either increasing the metabolism of the medication or reducing the absorption.

Rifampin (Rifaximin), an antibiotic given for bacterial gastrointestinal infections, actually increases the absorption of thyroid medication and can cause over medication to occur, resulting in hyperthyroid symptoms.

While antibiotics serve their purpose, it’s important to take them 4 to 6 hours either before or after your thyroid medication.

Sucralfate (Carafate), a medication often prescribed for treatment of peptic ulcer disease or gastroesophageal reflux disease (GERD) decreases the absorption of thyroid medication and should be taken 4 – 6 hours before or after.

Antidepressants: Many selective serotonin reuptake inhibitors (SSRI) like Prozac, Zoloft, and Paxil decrease the effectiveness of thyroid medication.

Anti-seizure: Medications such as Tegretol, Dilantin, and Phenobarbital increase the metabolism and may require your physician to increase your thyroid dose.

All of these medications can seriously impact your thyroid health and the absorption of your thyroid medication. It is important to speak with your physician regarding your medication.


Interestingly, taking iron or calcium supplements, while helpful to your condition, can also affect the way your body absorbs your medication. Even reaching for an over the counter antacid like Tums or Rolaids, needs to be taken into consideration, if you are currently taking any type of thyroid medication, observe the 4 to 6 hour rule.


Similar to supplements, foods rich in iron, fiber, or calcium such as calcium fortified orange juice or yogurt should enjoyed at least 2 hours before or after taking your thyroid.

Many times we seek different doctors for different reasons. While your endocrinologist could be prescribing your thyroid medication, the general family doctor you seek when sick with bacterial, viral, or maybe stomach issues is completely unaware of any other prescriptions. And we often times forget to mention the over the counter drugs we take, not giving the doctor the whole picture. It is always best to try and keep a list of medication, including supplements, handy to share with each doctor that you see.

Simple observations of these time guidelines can make a huge difference in keeping your thyroid gland and medication performing at its best.

About Holtorf Medical Group

The Holtorf Medical Group specializes in optimizing quality of life and being medical detectives to uncover the underlying cause of symptoms, rather than just prescribing medications to cover-up the symptoms. We are experts in natural, prescription bioidentical hormone replacement and optimization, complex endocrine dysfunction, fibromyalgia, chronic fatigue syndrome and Lyme disease.

We’ve dedicated our practice to providing you the best in evidenced-based, integrative medicine that’s not only safe and effective, but provides measurable results.