Now let’s talk about hypothyroidism, something that’s very common in the United States. In hypothyroidism, the gland is not producing enough hormone and it has nothing to do with the diet. It just has to do with the fact that the thyroid is not producing enough hormone.
In an adult this is called myxedema and the symptoms include, drowsiness, slowed speech, decreased cardiac output, and skeletal muscle weakness. This makes sense because everything in the body is slowing down.
In a child this is called cretinism and this is much more serious. This is a congenital malformation of the thyroid gland. If we don’t replace what’s missing, the child will have mental retardation and fail to grow.
Thyroid Replacement Medications
Levothyroxine (Synthroid): One of the most common utilized agents is synthetic T4 called levothyroxine (Synthroid, Lavoxil).  The body converts T4 to T3 as it’s needed. The caution with this drug is that it blocks the absorption of minerals from food.  Taking this as the first thing in the morning makes the most sense because it is difficult to sleep if you take this in the evening since it ramps up metabolic activity.  Usually people leave it by their bed and take it first thing in the morning and eat an hour afterwards.
Liothyronine (Cytomel): Another option is liothyronine which is synthetic T3, the active hormone. This medication is in minute (microgram) doses and works right away as you consume it. It must be dosed properly because it puts a strain on the heart if one takes too much. We usually use this drug in combination with T4. The individual getting this drug usually has severe hypothyroidism to the point where they have trouble getting up in the morning and the T3 helps (maybe they had the thyroid removed). If they got only T4, they can’t go through the first few hours of the morning because the T4 needs to get converted.
Thyroid tablet: A thyroid tablet is a dessicated thyroid gland from a cattle slaughterhouse  They dessicate the gland and form it into a tablet. What’s in that gland? T3 or T4? There’s both of them!
Individuals who are very sensitive may have a problem with this.  An individual may take a certain milligram amount of this a day. But what is it milligrams of? We don’t know exactly how much T3 or T4 there is. For some individuals on the high-end dose notice a difference every time they refill their prescription because it’s coming from a different animal each time. The advantage to this is that it’s one pill instead of two. It tends to be a little less expensive than the others.
With most drugs there is absolutely no controversy between generics and brand names.   There’s a lot of controversy about generic thyroid medications.  Up until the mid 2000’s, the FDA said there is no substitution allowed with thyroid medication. If the doctor wrote Synthroid, you couldn’t get levothyroxine. The FDA, against the manufacturers wishes, eventually said that it’s okay to take a generic. Some patients who made the switch said that there was a difference.  We aren’t sure if there really is one but it’s reported that way for this class of medication for some reason.
Recap
- Levothyroxine – synthetic thyroxine (T-4)
- Minerals inhibit absorption
- Liothyronine – synthetic T-3 (active hormone)
- Thyroid Tablet – Dessicated thyroid gland from cattle – mixed T3 and T4
- Lot to lot variation
