What Are the Different Types of Thyroxine Tablets?

Thyroxine tablets vary by dosage, color, shape and inactive ingredients. They also may be called different names, and other popular generic names are levothyroxine or T₄, while the best known brand name is Synthroid®. Occasionally, thyroxine tablets also include triiodothyronine, which is the other major thyroid replacement hormone, also known as T₃. Combination pills with both thyroid hormones may be sold under the generic name, liotrix, and they differ in appearance, shape, and dosage.

There are many different doses of thyroxine tablets available. This medication is potent and all the doses are measured in micrograms (mcg). The lowest strengths may begin at 25 mcg. There are four more strengths of pills with varied doses up to 100 mcg.

Seven additional dosage strengths occur after 100 mg, and the maximum amount available in a single tablet is 300 mcg. The huge range in dose is accounted for by the fact that thyroid replacement is highly sensitive and individualized. Taking 10-15 mcg less or more can mean the difference between a positive or negative response to the drug.

Patients using this medication may also notice that thyroxine tablets come in numerous colors. Standard pastels in muted yellows, oranges, greens and blues are as common as white pills. Some manufacturers prefer to dye the tablets deeper colors, and it’s not uncommon to find bright orange, purple, pink, or dark blue. Colors don’t necessarily universally correspond to a specific dosage, and one manufacturer may use a different color than another for the same strength tablets.

Less varied are the shapes of thyroxine tablets. They can either be round or oval/elliptical. Sometimes, the pills are scored, which makes them easier to split. At other times, the tablet is only scored on the top and bottom, but the scoring doesn’t form a continuous line.

The types of inactive ingredients that might be in thyroxine tablets will vary. Different dyes are used to produce muted or florid colors. Most pills will have some similar basic ingredients like lactose, a small amount of sugar, and talc. It may be possible to find a drug that lacks ingredients to which an individual is sensitive because there are so many manufacturers.

Patients should not confuse any form of thyroxine tablets with liotrix pills. This drug combines levothyroxine with T₃, which may be useful for some individuals who need T₄ and T₃ thyroid hormone replacement. These tablets may also be round or oval, have numerous colors, and come in a variety of doses. Unlike in levothyroxine tablets, the highest thyroxine dosage in liotrix is 150 mcg. Higher strengths of thyroxine usually aren’t necessary due to the supplementation of T₃ at the same time.