• linkedin


Patient outcomes with thyroid therapy are determined by many factors. Physicians often simply increase the dosage in order to achieve the desired treatment goal. As a pharmacist, you should help them look at the bigger picture.


#1: Excipients

One factor could be the excipients in the product.1

Several years ago, a study showed that when a manufacturer of levothyroxine (T4) changed the source of the formulation ingredients, there was a change in TSH suppression. The controversy over changing brands of T4 is ongoing due to differences in bioavailability. The result of this controversy provides you with an opportunity to make a difference in patient care.

With the ability to compound custom formulations, you are able to choose from a variety of excipients and can pick the one that best suits the individual. For example, a case report of levothyroxine malabsorption was observed in a lactose-intolerant patient.2 Individuals who have problems with lactose might not be aware of the intolerance. Lactose may not be the best choice for patients, yet many commercial products still contain it.

LoxOral™ (PCCA # 30-4774) is an excellent excipient choice for patients who are not responding to their current formulation of thyroid. We certainly would not recommend changing patients who are stable. However, for a new or current patient who is not doing well, LoxOral could improve the dissolution and provide a more evenly distributed preparation. LoxOral is not only lactose-free, but also free from gluten, casein, soy, sodium lauryl sulfate, dye and magnesium sulfate.

Another option is an oil-based suspension. Patients with poor GI health may have difficulty even breaking down the capsule. A study was conducted with an alcohol and glycerin oral solution that was mixed with standard breakfast beverages, including coffee. As long as the dose was consumed within 20 minutes, there was not a significant difference in the stability of T4.3 More research needs to be done on this, but could provide you with an alternative for the patient who isn’t absorbing.

As you continue looking at the bigger picture, you should also recommend a probiotic (such as Wellness Works #10224, Extra Strength Probiotic) as well as other nutritional supplements to help the GI tract or aid in digestion. The health of the patient is determined by the health of the GI tract. We are not what we eat, but what we absorb!


#2: Interference With Other Drugs

Concomitant use with certain foods and/or medications can be a reason for inadequate levels.2

Most physicians are aware of the interference that iron, calcium, bileacid sequestrants, sucralfate and aluminum-containing antacids have with thyroid absorption. As new drugs enter the market, you need to think of what else could interfere.

There have been several case reports of elevated TSH with patients taking the selective estrogen receptor modulator (SERM) raloxifene. Separate from its effect on thyroxine-binding globulin, researchers concluded that it also had an effect on absorption.

Proton pump inhibitors (PPI) could also play a role in decreased T4 levels. It is possible that gastric acid is needed for the absorption of T4. Although some of the research is conflicting with regards to PPIs, the conflict could be explained partly by length of therapy of the PPI. The patients on long-term PPI did show an increase in TSH, while the short-term therapy did not significantly alter levels.2


#3: Disorders of The Gut

Disorders of the GI tract can affect the bioavailability of T4 by either reducing absorption or affecting pH.

Celiac disease appears to have a strong correlation with elevated TSH levels in patients on thyroid replacement. This could be attributed partly to malabsorption of the medication, but there is also a common link between celiac and autoimmune thyroid disorder. The simple solution is to have the patient remove gluten from their diet. Since the symptoms of celiac can sometimes be subtle, the patient might not make the connection.

Another study showed that patients on levothyroxine had a decrease in TSH suppression when H. pylori infection existed. The bacterial production of urease can neutralize gastric pH. After proper treatment of the infection, TSH levels return to normal.2

Understanding how GI disorders can affect thyroid levels gives you opportunities to ask more questions and solve more patient problems.


Take-Home Messages

  • Look beyond the strength of the thyroid medication the patient is taking if goals aren’t achieved.
  • Examine the health of the patient’s GI tract. Simple solutions such as eliminating gluten from the diet or testing for H. pylori could be the game-changer.
  • Question the other medications or supplements the patient is taking and timing with the thyroid dose.
  • If you have examined all obvious reasons and there is still a problem with getting the desired level, change the excipient or try a different delivery system.



  1. Olveira G, Almarez MC, Soriguer F, Garriga MJ, Gonzalez-Romero S, Tinahones F, Ruiz de Adana MS. Altered bioavailability due to changes in the formulation of a commercial preparation of levothyroxine in patients with differentiated thyroid carcinoma. Clin Endocrinol 1997 Jun;46(6):707-11.
  2. Liwanpo L, Hershmann JM. Conditions and drugs interfering with thyroxine absorption. Best Practice & Research Clinical Endocrinology & Metabolism 23 (2009), 781-792.
  3. Bernareggi A, Grata E, Pinorini MT, Conti A. Oral liquid formulation of levothyroxine is stable in breakfast beverages and may improve thyroid patient compliance. Pharmaceutics 5 (2013), 621-633.



Take the next step.

Immediately unlock the savings potential on customizable marketing materials, videos on demand and educational events for you and your invited prescribers.