Liothyronine is used to treat hypothyroidism (low blood levels of thyroid hormone), goiter (swelling in the thyroid gland), and myxedema (the body's changes associated with prolonged low blood levels of thyroid hormone). It may also be used to aid the diagnosis of hyperthyroidism (high levels of thyroid hormone).

Thyroid replacement therapy such as liothyronine is used when the thyroid gland does not secrete enough thyroid hormone (hypothyroidism). Thyroid hormone is necessary for maintaining the correct metabolic rate of body tissues. Liothyronine works quickly to restore the normal function of tissues and organs and must be taken on a daily basis to be effective. Replacement thyroid hormone therapy usually needs to be taken for life.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

The starting adult dose of liothyronine to treat hypothyroidism is 25 µg daily. Based on the results of laboratory tests to determine the amount of thyroid hormone in your blood, your doctor will increase your dose of liothyronine gradually, every 1 to 2 weeks until an appropriate level of thyroid hormone is available in the bloodstream. Do not change the way you take this medication without consulting your doctor.

The starting dose of liothyronine for children when treating hypothyroidism is 5 µg daily, which will be increased every 3 to 4 days until an appropriate response occurs.

The starting adult dose of liothyronine to treat goiter or myxedema is 5 µg daily. Again, based on blood tests, your doctor will gradually increase your dose of liothyronine every 1 to 2 weeks until an appropriate response occurs.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones given here, do not change the way that you are taking the medication without consulting your doctor.

This medication is to be taken once daily, usually before breakfast. Replacement thyroid hormone therapy usually needs to be taken for life.

It is important to take this medication exactly as prescribed by your doctor. If you miss a dose, take it as soon as possible and continue with your regular schedule. If it is almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store this medication at room temperature and protect it from heat, light and moisture. Keep out of reach of children.

5 µg
Each round, flat-faced, bevelled-edged, compressed white-to-off-white tablet, embossed with "KPI" on one side and "115" on the other side, contains liothyronine sodium equivalent to liothyronine 5 µg. Nonmedicinal ingredients: calcium sulfate, gelatin, starch, stearic acid, sucrose, and talc.

25 µg
Each round, flat-faced, bevelled-edged, compressed white-to-off-white tablet, embossed with "KPI116" on one side and scored on the other side, contains liothyronine sodium equivalent to liothyronine 25 µg. Nonmedicinal ingredients: calcium sulfate, gelatin, starch, stearic acid, sucrose, and talc.

Do not take liothyronine if you:

• are allergic to liothyronine or any ingredients of the medication
• have certain uncorrected problems of the adrenal glands
• have recently had a heart attack

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• headache

Although most of these side effects listed below don't happen very often, they could lead to serious problems if you do not check with your doctor or seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• confusion
• diarrhea
• dizziness
• fast or irregular heartbeat
• fatigue
• fever
• increased appetite
• menstrual changes
• sweating
• signs of an allergic skin reaction (e.g., rash, itchiness)
• trouble sleeping
• weight loss

Stop taking the medication and seek immediate medical attention if any of the following occur:

• chest pain
• signs of a heart attack (e.g., chest pain, anxiety, pressure or squeezing sensation in the chest, paleness, shortness of breath, pain spreading to shoulders, neck, jaw)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Bone density: Long term use of thyroid mediations can cause bones to lose thickness. If you have an increased risk for osteoporosis (bone thinning) or are taking medications that reduce bone thickness (e.g., prednisone or antiseizure medications), before you start taking this medication, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Diabetes: Liothyronine may cause blood sugar to increase and glucose tolerance may change. People with diabetes may find it necessary to monitor their blood sugar more frequently while using this medication.

If you have diabetes or are at risk for developing diabetes, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Heart disease: Starting liothyronine may cause the heart to work harder than it has been used to. This can cause symptoms of angina or other heart disease to worsen. If you have angina or other heart disease, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Pregnancy: Liothyronine does not cross the placenta, therefore it does not directly affect the development of an unborn baby. During pregnancy, your doctor will probably want to do blood tests to make sure the level of thyroid in the blood stream is appropriate. This medication is safe to use during pregnancy.

Breast-feeding: This medication passes into breast milk in small amounts. It is important to continue taking thyroid hormone even when you are breast-feeding. Inform your doctor if you are breast-feeding or intending to breast-feed while taking liothyronine.

Seniors: Older people may be more sensitive to the effects of liothyronine and should be watchful for side effects, particularly those involving the heart.

There may be an interaction between liothyronine and any of the following:

• amiodarone
• amoxapine
• antacids that contain aluminum or calcium
• apalutamide
• birth control pills
• calcium polystyrene
• calcium supplements (e.g., calcium carbonate, calcium citrate)
• carbamazepine
• cholestyramine
• ciprofloxacin
• colesevelam
• colestipol
• digoxin
• estrogens (e.g., conjugated estrogen, estradiol, ethinyl estradiol)
• lanthanum
• phenytoin
• rifampin
• ritonavir
• simethicone
• sodium iodide I131
• sodium polystyrene
• selective serotonin reuptake inhibitors (SSRIs; e.g., citalopram, fluoxetine, paroxetine, sertraline)
• theophyllines (e.g., aminophylline, oxtriphylline, theophylline)
• tricyclic antidepressants (e.g., amitriptyline, imipramine)
• warfarin

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications that you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.