Thursday, July 16, 2020

A look at three thyroid hormone replacement options after thyroid cancer or for the hypothyroid patient

One thing that I have learned about thyroid hormone replacement in thyroid cancer patients, or in those who are hypothyroid, is that there is no " one size fits all" when it comes to treating the individual. I am going to discuss three of the main line treatments for replacement of thyroid hormone, used by endocrinologists and other general physicians.

1.) Levothyroxine drugs only. These include brand name drugs like Synthroid, Levoxyl, and Tirosint. These drugs contain ONLY the T4 hormone. The T4 hormone is inactive. This means that the body has to convert the T4 into the active form of the thyroid hormone, or T3. A note about Tirosint. It differs from the other brand name drugs in that it does not contain some allergens, like gluten, lactose, sugars, dyes and talc- to name a few. The company says that people who have intestinal disorders, such as celiac disease,GI reflux,inflammatory bowel disease, and other GI disorders where absorption may be an issue, may benefit  from taking Tirosint. And by benefit, the company says that absorption may be better, leading to better thyroid hormone blood levels. I have not seen any studies personally, so take this with a grain of salt. Personally, I have heard some others who did like the Tirosint, and said that it did make them feel better. Again, no one size fits all, and thyroid hormone replacement is really a trial and error event.

Pros: Only one medication that the patient has to take. Tirosint MAY be helpful in people who have celiac disease, other GI disorders, or allergies to additives in the other T4 only drugs listed.

Cons: Tirosint is VERY EXPENSIVE, as are some other brand names. And most importantly of all, for some of us, our bodies do not convert T4 to the active T3 very well, and that means that hypothyroid symptoms will be present, i,e, our treatment will be less effective and we will not feel well. As for the generic levothyroxine medications, the potency can differ from one manufacturer to another,leading to inconsistent blood values and treatment failures. It is recommended that if a patient switches from one manufacturer to another, blood work should be done to insure that the patient has good T4 ,T3 and TSH levels.

2.) T3 ( triiodothyronine)  AND T4 ( Levothyroxine) given as a two drug regiment. If our bodies, for whatever reason, can not convert T4 to adequate amounts of T3, then  it makes sense to supplement with T3, right?  Not all endocrinologists and general family physicians will prescribe T3, and the reasons why will be listed in the "cons' section.

Pros: most patients report feeling better when a T3 drug ( Brand name : Cytomel, but generic is available, at a lower cost )  is added to their regiment. It is, after all, the energy portion of this combo- the gas that drives the car, one might say. In using this two drug approach, the physician can tweak the dosage, and is not locked into a fixed amount of T3- as will be discussed in the third option of treatment.

Cons: the patient has to take two different drugs for thyroid hormone replacement. The reason that not all endocrinologists or family physicians are comfortable prescribing a T3 medication, is that it can cause nervousness, headache, nausea, difficulty sleeping, and in rare cases when too much T3 is present- chest pain, irregular heartbeat, swelling of the ankles and/or feet, trouble breathing and unusual tiredness. This is where, I think, it is essential to have a physician who is comfortable with  and has experience in prescribing a T3 drug.

3.) Naturally sourced thyroid replacement drugs- ( NDT).  These are derived from natural sources, namely the desiccated ( dried) thyroid glands of pigs( usually, although there are some NDT from other countries that use desiccated cow thyroid glands). This medicine is measured in grains, not mcg as the traditional T4 and T3 drugs. Some  examples of this drug are Nature-Throid, WP Thyroid, and Armour. According to the information on the Nature-Throid website, each grain of Nature-Throid contains 38mcg of T4 and 9mcg of T3. WP thyroid brand has the same mcg of T4 and T3 as the Nature-Throid, while Armour thyroid brand has  slightly less.  The manufacturers of the Nature-throid suggest that due to its "higher bioactivity" physicians should probably choose a slightly lower dose for those patients who are converting from a synthetic hormone replacement drug to the NDT.

Pros: some people prefer a NDT type drug. Nature-throid does not contain any artificial colors or flavors, or any corn, peanut, rice, gluten, soy, yeast, egg, fish or shellfish( according to the manufacturers website). There is only one tablet to take, instead of two tablets  like option number two.

Cons: because it is a fixed ratio of T4 and T3, it is more difficult to dose if the patient needs less of one hormone or the other. In other words, dosing is not as flexible as it would be in option number two. Some physicians are concerned that a NDT type drug will not have consistent ingredients from tablet to tablet. This has not been proven, and may be an argument/marketing strategy coming from companies who manufacture synthetic T3 and T4 type medications. One problem that I have encountered  in my years of practicing pharmacy, is that these NDT tablets  smell really bad! If the drugs are stored in the refrigerator, it reduces the smell quite a bit. Another consideration is that people who have the Alpha-gal disease, can not take NDT drugs due to their  extreme allergy to red meat and pork products.

So, one size does not fit all when it comes to thyroid replacement hormone therapy! There are pros and cons to all of the above three regiments. Many factors must be considered when choosing what type of hormone replacement(s) is right for a patient. Careful discussion and a good doctor/patient  relationship  with an endocrinologist or family physician is key to success in treatment. Even so, there will be many dosage changes, and probably medication changes over the course of a patient's lifetime. Life situations change, patient health conditions change, sometimes there are changes in the manufacturing of a particular drug, or there is a shortage or back order of a medication- these are just a few instances where adjustments to medications would need to be made.

There are, however, a few tips that apply to all thyroid hormone replacement drugs. These drugs are heat sensitive. Store them away from heat, humidity, and direct sunlight. Mail order may not be the best option now, unless the company ships them with some type of cold pack. If possible, pick them up from a pharmacy. Thyroid medications work best when taken at the same time each day ( most people take theirs in the morning) - on an empty stomach with a full glass of water. Wait an hour before eating or drinking anything else for best absorption. If you are taking calcium supplements and/or vitamins containing iron, you will need to wait at least 4 hours before taking the them to ensure good absorption. When a patient switches from brand to generic, generic to brand, or even one generic to another generic manufacturer, it is recommended that the TSH and perhaps other thyroid tests  be checked in 6-8 weeks after the switch to make sure that the TSH,etc, are not affected. 

What about me, you may be wondering? Which treatment option did I choose? Believe it or not, I have tried all three! The one that seems to be working best for me now is option number two. I like the flexibility in dosing by having the T3 and T4 as separate medications. This could always change, as my body is changing, I am getting older (!) , and my health issues are changing. Like I said, there is NO ONE CHOICE THAT FITS ALL!

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