Ask the Pharmacist

Q) I haven’t felt like myself for a while now. I finally saw my doctor who ran a bunch of blood tests on me. The results that came back indicated that I have subclinical hypothyroidism. What the heck is that and how did I get this?

A) While your thyroid hormones don’t generate the level of attention that our dominant sex hormones do (i.e. testosterone and estrogen) perhaps they should considering what a massive impact they have on just about every aspect of our lives.

This 2 inch gland plays a major role in regulating our metabolism, heart rate, body temperature, bowel movements and our brain function. When our levels go above or below certain thresholds, we tend to feel it in a variety of unpleasant ways.

When the levels are too low, a condition known as hypothyroidism, people can feel sad/ depressed, colder than everybody else in the room, they can put on a few unexplained pounds, feel fatigued, find it hard to think and notice that their skin and hair have become very dry (and thinner in the case of your hair). They may also experience soreness in their joints or muscles, feel weak, be constipated and have trouble remembering things.

A lot of these symptoms are what health professionals deem non-specific, meaning that they could be caused by any number of other conditions and in fact many are associated with aging to some extent causing hypothyroidism to often go undetected for many years. This can be especially true amongst its most prevalent population, females over the age of 60.

With subclinical hypothyroidism (also known as mild thyroid failure) the thyroid hormones produced by the thyroid gland are still within the normal range but the levels of another hormone known as the thyroid stimulating hormone (TSH) which is produced by the pituitary gland is a little above normal.

Normally, the pituitary gland produces more TSH when it notices that the body is lacking enough in circulating thyroid hormone. The job of this TSH is to stimulate the thyroid gland to produce more of our thyroid hormones, namely T3 and T4 (mostly T4 is produced which is then subsequently changed by our body into T3, the “active” form as is required). Research indicates that between 3 to 8 percent of people have subclinical thyroidism and that as many as one quarter of these will progress to full-blown hypothyroidism within 6 years of their original diagnosis.

The causes of subclinical hypothyroidism are the same as they are for plain old hypothyroidism. These include an autoimmune disorder that causes your immune system to attack the thyroid’s cells (known as Hashimoto’s disease) for reasons scientists are still unclear about, an injury to the thyroid gland (from surgery done in that area or secondary to radiation treatment in the head or region), as an over-response to treatment for an overly active thyroid, or as a result of taking certain medications (such as lithium).

Less common reasons for people to be diagnosed with hypothyroidism are a deficiency in iodine, as a complication of pregnancy or as a result of a disorder of the pituitary gland.

People most likely to have either subclinical or regular hypothyroidism beyond the risk factors of being female and over the age of 60 include those with a family history of thyroid disease and those who already have another type of autoimmune disorder (such as lupus or celiac’s disease) as these types of disorders regrettably seem to frequently occur together.

Treatment is almost always in the form of a pill using an ingredient called levothyroxine which mimics the action of our depleted thyroid hormones. The dose is based on our measured blood levels and is usually rechecked three months after starting therapy. For most people, it is a very good treatment that makes many of the symptoms listed above “go away” and gives them what feels like a new lease on life.

However, there are some people who still do not feel “right” despite blood work indicating that their thyroid levels are normal. For some people, a possible solution would be to speak to the prescribing physician about the possibility of adjusting the dose so that it is in the higher or lower range of normal (for instance, the “normal” range of TSH goes from 0.5 to 5 which is really quite broad) depending upon whether your feelings of not being well are more indicative of having too much or too little thyroid.

This feeling of “unwellness” could also be a result of taking your replacement pill with food, a dairy product, caffeine or a vitamin supplement that contains minerals such as calcium or iron. These can decrease the amount of thyroid replacement that reaches your bloodstream thereby limiting its effectiveness in a highly variable manner.

Try to take levothyroxine 30 minutes, or even better, an hour before breakfast and hold off on supplements with minerals for at least 4 hours afterwards. Conversely, some people who do not wish to wait for their morning coffee or don’t get up much before breakfast have chosen to take their dose in the evening. This can work well as long as it is at least 4 hours since the last intake of food or milk.

In fact, one study found that moving the dose to the evening increased blood levels of the hormone even amongst people who were previously following all the rules for ideal absorption when they were taking it in the morning. Speculation behind what to make of this improvement focuses on the fact that the conversion of inactive T4 to active T3 may be more effective in the evening and that bowel transit times tend to be slower which allows the tablet to have more exposure to the intestinal wall and hence increased absorption.

One last, perhaps controversial possibility for those who still feel “off” is to talk to their prescriber about switching to a “natural” thyroid replacement or adding a drug such as Cytomel (T3) to their regular levothyroxine tablet. These are not the standards of care and come with some degree of risk as a result of possibly having excess hormone in your bloodstream (which can lead to heart rhythm abnormalities or accelerated bone loss amongst many other symptoms) so there are many physicians who would not be comfortable in supporting this but it remains a possibility for some.