Danna Bowman, Founder
Thyroid Nation

Antibiotics Interfere With Thyroid Hormone

Just recently, I was down and out with bronchitis. I tried the best I could to heal myself using all natural remedies. Lemon, astragalus, ginger, vitamin C, rest and more rest, water and essential oils where on the daily menu. Eating garlic every day might help your immune system, but it doesn’t do much for getting snuggles from you family. Although I do think that all of my efforts helped a great deal, I also think it just prolonged the inevitable….my trip to the doctor.

Eventually, my coughing became so severe that I finally broke down and went to the doctor. (Actually, I was taken by the hand and driven to the appointment by my husband. It seems he was ready to get some sleep and I had been keeping him up all night, every night…oops!). I was prescribed a weeks worth of prescription medications including amoxicillan and prednisone. I remember being less than thrilled about either.

I also suffer with Hashimoto’s and my adrenals are out of whack.

Wondering if these would counteract my thyroid medication, Nature-Throid, I took to the internet.

Per the Holtorf Medical Group,

If you are hypothyroid and taking a prescription thyroid hormone replacement drug like levothyroxine (i.e., Synthroid, Levoxyl, Tirosint) and you are prescribed an antibiotic, you will want to make sure that you know about how thyroid drugs and antibiotics can interact, affecting the absorption of your thyroid medication.

A study from the journal Thyroid found that the antibiotic ciprofloxacin – known more commonly by brand names Cipro, Proquin, Ciproxin, Ciprobay, Cirpoxine, and Ciflox — significantly decreased the absorption of the thyroid medication. [Keep in mind that some experts feel that the warning about ciprofloxacin applies also to similar quinolone antibiotics such as levofloxacin (Levaquin), lomefloxacin (Maxaquin), monifloxacin (Avelox), norfloxacin (Norox-In), and ofloxacin (Floxin).]

This means that if you are taking thyroid drugs and an antibiotic from the quinolone family, it could interfere with absorption, and cause you to become substantially more hypothyroid.

Interestingly, there are other antibiotics that significantly increased the absorption of thyroid medications.


Mary Shomon explains what happens with antibiotics is that they can have several effects:

-They may be decreasing your absorption of the levothyroxine you are taking, resulting in lower circulating blood levels of thyroid medication in your bloodstream

-They may increase the rate at which your body metabolizes and gets rid of the levothyoxine, again resulting in lower circulating blood levels of thyroid medication in your bloodstream

-They may change the way levothyroxine binds to proteins in in your bloodstream and is absorbed, affecting your thyroid levels as well.

What I learned in my quest for knowledge was that I could experience many symptoms including that of being overmedicated or hyperthyroid, while taking antibiotics. At the same time, still have exacerbated hypothyroid symptoms.

According to Functional Medicine University,

Combining quinolone antibiotics with Levothyroxine (a T4 drug) may lead to reduced absorption of thyroid medicine and cause changes in TSH.

I’m working to find the perfect balance for me with having to take antibiotics while taking thyroid medication. When you don’t feel well and can’t think, it can be extremely difficult to do, but it can be done. Ask for help. Use a pill box. And think about being healthy. Our thoughts have an effect on our cells. Stay positive! Be nice to your cells.

Thyroid-Diet-Ad-Banner2What can you do?

Spacing your thyroid hormone medications away from your antibiotics, might be helpful but hasn’t been proven in any studies. It is always a good idea to err on the side of caution; however.

Make sure you talk with your healthcare provider before agreeing to take any antibiotics if you are on thyroid hormone medications.

And don’t forget to replenish your gut with healthy probiotics.

Stay up-to-date, get tips, articles and stories that inspire, on all things thyroid!

About the Author

danna-bowman-thyroid-nation-profile-1Danna Bowman is the founder of Thyroid Nation. She developed Hashimoto’s after years of unknowingly suffering with hypothyroidism, hormonal imbalances and adrenal fatigue… a real-life roller coaster. Hypothyroidism runs in her family but it was never discussed, unfortunately. Her husband, 2 kids and her, picked up and moved, sight unseen, from Texas to Costa Rica in 2008. She was accurately diagnosed, however, they only offer Levothyroxine or Thyroidectomy as a solution for the disease. After a year of suffering, she turned to the internet and found a doctor in Arizona that would consult with her and prescribe Natural Dessicated Thyroid. After learning and realizing the misinformation and lack of information in Costa Rica and worldwide, she founded the website to help educate others. In 2015, she launched Thyroid Nation RADIO, a weekly thyroid and health, LIVE radio show with her co-host, Tiffany Mladinich. In 2016, together they created a thyroid-friendly, face/body product line of essential oils blends that smell fabulous and are good for you.

PLEASE take a moment to ‘Like’ us on Facebook and follow us on Twitter and Pinterest. You can also listen to Tiffany and I on Thyroid Nation RADIO.

Questions or anything to ask about antibiotics? We want your thoughts –Please! You might be able to help someone else in need with your comment.

Holtorf Medical Group
Functional Medicine University
Thyroid About.com