Medically reviewed by Drugs.com. Last updated on Nov 12, 2022.
Thyroid hormones, including liothyronine sodium, either alone or with other therapeutic agents, should not be used for the treatment of obesity or for weight loss. In euthyroid patients, doses within the range of daily hormonal requirements are ineffective for weight reduction. Larger doses may produce serious or even life-threatening manifestations of toxicity, particularly when given in association with sympathomimetic amines such as those used for their anorectic effects .
Commonly used brand name(s)
In the U.S.
Available Dosage Forms:
Therapeutic Class: Thyroid Supplement
Uses for Cytomel
Liothyronine is used to treat hypothyroidism, a condition wherein the thyroid gland does not produce enough thyroid hormone. It is also used to help decrease the size of enlarged thyroid glands (goiter) and treat thyroid cancer.
Liothyronine is also used in some medical tests to help diagnose problems with the thyroid gland.
This medicine is available only with your doctor's prescription.
Before using Cytomel
In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:
Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.
Appropriate studies performed to date have not demonstrated pediatric-specific problems that would limit the usefulness of liothyronine in children. Recommended doses should not be exceeded, and the patient should be carefully monitored during treatment.
Appropriate studies performed to date have not demonstrated geriatrics-specific problems that would limit the usefulness of liothyronine in the elderly. However, elderly patients are more likely to have age-related kidney or heart or blood vessel problems, which may require caution and an adjustment in the dose for patients receiving liothyronine.
There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.
Interactions with medicines
Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
- Sodium Polystyrene Sulfonate
Interactions with food/tobacco/alcohol
Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.
Other medical problems
The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:
- Adrenal insufficiency (underactive adrenal gland), uncorrected—Should not be used in patients with this condition.
- Adrenal gland problems or
- Angina (chest pain), history of or
- Blood clotting problems or
- Diabetes or
- Heart or blood vessel disease (eg, coronary artery disease, heart failure), history of or
- Heart rhythm problems (eg, arrhythmia, atrial fibrillation), history of—Use with caution. May make these conditions worse.
- Hypoproteinemia (low levels of protein in the blood), severe or
- Kidney disease (eg, nephrosis) or
- Liver disease (eg, hepatitis), severe or
- Pituitary gland problems (eg, acromegaly) or
- Porphyria (enzyme problem)—Use with caution. May need to adjust the dose of liothyronine in patients with these conditions.
Proper use of Cytomel
This medicine will need to be taken for the rest of your life of your child's life. Do not stop taking this medicine or change your doses without first checking with your doctor. It may take several weeks before you start to notice an improvement in your symptoms.
If you use medicine to treat high cholesterol (including cholestyramine, colesevelam, colestipol), Kayexalate®, or sevelamer, take liothyronine at least 4 hours before you take any of these medicines.
The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.
The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.
- For oral dosage form (tablet):
- For hypothyroidism:
- Adults—At first, 25 micrograms (mcg) once a day. Your doctor may adjust your dose as needed. However, the dose is usually not more than 75 mcg once a day.
- Older adults—At first, 5 mcg once a day. Your doctor may adjust your dose as needed.
- Children—At first, 5 mcg once a day. Your doctor may adjust your dose as needed.
- For thyroid cancer:
- Adults and children—Use and dose must be determined by your doctor.
- For thyroid problem diagnosis:
- Adults— 75 to 100 micrograms (mcg) once a day for 7 days. Your doctor will give you a radioactive iodine before and after the 7-day liothyronine.
- Children—Use and dose must be determined by your doctor.
- For hypothyroidism:
If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.
Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.
Keep out of the reach of children.
Do not keep outdated medicine or medicine no longer needed.
Ask your healthcare professional how you should dispose of any medicine you do not use.
Precautions while using Cytomel
It is very important that your doctor check your or your child's progress at regular visits. This will allow your doctor to see if the medicine is working properly and to decide if you should continue to take it. Blood tests will be needed to check for unwanted effects.
Liothyronine should not be used for the treatment of obesity or for the purpose of losing weight. This medicine is ineffective for weight reduction and when taken in larger amounts, may cause more serious unwanted effects.
Call your doctor right away if you start to have chest pain, fast or irregular heartbeat, excessive sweating, difficulty with breathing, heat intolerance, nervousness, leg cramps, headache, irritability, sleeplessness, tremors, change in appetite, weight gain or loss, vomiting, diarrhea, fever, changes in menstrual periods, hives, or skin rash. These could be symptoms of too much medicine in your body.
This medicine may cause severe hypothyroidism, called myxedema coma, which may be life-threatening and requires immediate medical attention. Check with your doctor right away if you have the following symptoms: weakness, confusion or non-responsiveness, feeling cold, low body temperature, swelling of the body, especially the face, tongue, and lower legs, or difficulty breathing.
For patients with diabetes: It is very important that you keep track of your blood or urine sugar levels as instructed by your doctor. Check with your doctor right away if you notice any changes in your sugar levels.
If you think you have become pregnant while using this medicine, tell your doctor right away. You may need a larger dose of liothyronine while you are pregnant.
Women who are post-menopausal or who use this medicine for a long time may have some bone loss, which could lead to osteoporosis. Talk with your doctor if you have questions or concerns about this.
A temporary loss of hair may occur during the first few months of liothyronine treatment. Ask your doctor about this if you have any concerns.
Make sure any doctor or dentist who treats you knows that you or your child are using this medicine.
Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.
Cytomel side effects
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur:
Incidence not known
- arm, back, or jaw pain
- blurred or double vision
- chest pain or discomfort
- chest tightness or heaviness
- decreased bone mineral density
- decreased urine output
- delusions of persecution, mistrust, suspiciousness, or combativeness
- difficulty breathing
- dilated neck vein
- extreme tiredness or weakness
- eye pain
- false or unusual sense of well-being
- fast, pounding, or irregular heartbeat or pulse
- feeling of discomfort
- feeling of unreality
- heat intolerance
- impaired fertility
- increased appetite
- increased blood pressure
- irregular breathing
- itching, skin rash
- joint swelling
- limp pain in the hip or knee
- menstrual changes
- mental depression
- muscle aches, weakness, or cramps
- pain or discomfort in the arms, jaw, back, or neck
- quick to react or overreact emotionally
- rapidly changing moods
- sense of detachment from self or body
- severe headache
- slow heartbeat
- stomach cramps
- swelling of the face, fingers, feet, or lower legs
- swollen lymph glands
- trouble sitting still
- trouble sleeping
- weight gain or loss
Get emergency help immediately if any of the following symptoms of overdose occur:
Symptoms of overdose
- Cold, clammy skin
- confusion about identity, place, and time
- difficulty in speaking
- double vision
- fast, weak pulse
- inability to move the arms, legs, or facial muscles
- inability to speak
- loss of consciousness
- sensitivity to heat
- slow speech
- trouble sleeping
- weight loss
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
Incidence not known
- Feeling of warmth
- hair loss
- redness of the face, neck, arms, and occasionally, upper chest
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
Frequently asked questions
- Can I take Cytomel and Synthroid together?
- How long does Cytomel take to start working?
- Does Cytomel help with weight loss?
- How long does Cytomel stay in your system?
More about Cytomel (liothyronine)
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