By Curtis Alexander, Pharm.D.
Summary: Cytomel® is a good drug that unfortunately has a bad reputation with many doctors and endocrinologists because of the possibility of causing side effects. While you do have to take precautions in some patients, Cytomel has been proven very safe in clinical use and may even be a better option than the current standard of therapies for hypothyroidism.
Note: A lot of the information that you will see in the thyroid section is coming from my own personal experience. While I don’t know for sure (yet) if I have hypothyroidism I’m trying to get that figured out as we speak. But, I have done a ton of research on my own and have come to the conclusion that most providers (doctors) know less than they should. As I continue to research I’m going to do my best to fill in the gaps on the subject.
Cytomel is really a prime example. It’s a good drug that has helped a lot of people. But, because it isn’t touted as much by the drug reps and in the literature it’s shunned by the medical establishment. That’s too bad. It works and it’s safe. Not only that, it has a great deal of history behind it’s use. The following is basically a synopsis of Cytomel and what I feel a patient should know about the drug before they consider it. It may even be worthy of taking to your doctor or provider to discuss with him or her.
Background
Cytomel (liothyronine sodium – T3) is one of a handful of medications available on the market to treat hypothyroidism.
When your body produces thyroid hormones on it’s own, naturally, it produces both a mix of T4 (inactive) and T3 (active). With the T4 version being more predominant.
Cytomel contains only the active (T3) version of thyroid hormone. Because of this some doctors are scared to use it for for of ‘overdosing’ or causing ‘jitters’ and so forth in patients.
Dosage
Cytomel is available in three different strengths: 5mcg, 25mcg and 50mcg. The usually dosage can, and should vary, depending on the severity of the hypothyroidism and the patients response.
While many doctors still continue to base their dosing off lab values, other doctors are suggesting that dosing of any thyroid medication be determined off the patients clinical response instead. In short, keep adjusting the dose until the patient starts feeling better rather than what their TSH blood test shows.
Action in Your Body
Believe it or not, exactly how Cytomel acts in your body is not that well known. We do know that thyroid hormones in general increase oxygen consumption by most body tissues, increase your resting metabolic rate (with an accompanying increase in resting heart rate) and increase the metabolism of carbohydrates, lipids and proteins. This may explain why if you are truly hypothyroid you might have high cholesterol.
Also, thyroid hormones are of particular importance in the development of the central nervous system. Which explains why many hypothyroid patients have difficulty regulating body temperature and can have ‘cloudy’ thinking or difficulty remembering things.
Myth Busting and Safety of Cytomel
Up to 95% of the Cytomel dose that you take is absorbed into your system within 4 hours.
T3 is not firmly bound to proteins in your blood stream. What this means is that when it is absorbed it is readily available for use by your body rather than T4 which is a more highly bound version. This probably explains why T4 blood levels are higher as well as staying in your system longer.
Because of it’s activity in your body (quick onset of action and improved metabolic activity because it is already readily available to your bodies cells) many doctors are hesitant to offer Cytomel therapy to patients.
But in fact, the evidence that we have to date shows that Cytomel is a very safe and well tolerated medication. On the actual medication leaflet that comes with Cytomel the incidence of side effects are considered “rare”. If there are going to be any side effects there are likely to be similar to hyperthyroid. For example, nervousness, headache, irritability, increased bowel motility, fast heart rate and arrhythmia.
I can promise you this: I’ve looked at thousands of drug monographs over the years as a pharmacist. That’s the information packet that the FDA requires drug companies to include with the stock bottles of medications. Normally, the side effects section of a monograph is paragraphs and paragraphs – pages even – of charts and graphs depicting every little conceivable side effect that might occur.
Cytomel’s monograph (drug information sheet) is literally less than 100 words long. For a pharmacist that tells me Cytomel is safe. Normally these documents from the drug manufacturers read like War and Peace to make sure that they cover EVERY possible side effect, etc.
Legitimate Concern Over Cytomel’s Use
However, there are three main groups of patients who should use caution before taking Cytomel:
- Patients with diabetes
- Patients with cardiovascular disease. Especially those with a history of arrhythmia’s and angina.
- Patients on ‘blood thinners’ or anticoagulants.
