Dosing & Uses
Dosage Forms & Strengths
injectable solution
- 10mcg/mL
tablet
- 5mcg
- 25mcg
- 50mcg
Hypothyroidism
Initial: 25 mcg PO qDay; may increase by 25 mcg q1-2Weeks; not to exceed 100 mcg/day
Maintenance: 25-75 mcg PO qDay
May use 10-12.5 mcg T3 in combo with T4 (decrease T4 dose by 50 mcg)
Nontoxic Goiter
Initial: 5 mcg PO qDay; may increase by 5-10 mcg q1-2Weeks (5 mcg in elderly)
When reach 25 mcg PO qDay, may increase by 12.5 mcg or 25 mcg q1-2Weeks
Maintenance: 75 mcg PO qDay
Myxedema
Initial: 5 mcg PO qDay; may increase by 5-10 mcg/day q1-2Weeks
When reach 25 mcg PO qDay, may increase by 5-25 mcg q1-2Weeks
Maintenance: 50-100 mcg PO qDay
Myxedema Coma
Initial: 25-50 mcg IV
Patients with CVD: 10-20 mcg IV
Doses of at least 65 mcg/day IV associated with lower mortality
Allow 4-12 hr between doses; not to exceed 12 hours
Orphan Designations
Brain metastases: Orphan designation (plus methimazole) for brain metastases in patients with primary lung cancer
Glioblastoma multiforme: Orphan designation (plus methimazole) for treatment of glioblastoma multiforme
Sponsor
- Musli Thyropeutics Ltd; 6 Hagefen Street, P. O. Box 529; Zur Moshe, Israel
Dosage Forms & Strengths
injectable solution
- 10mcg/mL
tablet
- 5mcg
- 25mcg
- 50mcg
Congenital Hypothyroidism
Initial: 5 mcg PO qDay; may increase by 5 mcg q3-4Days
Maintenance
- <1 year: 20 mcg PO qDay
- 1-3 years: 50 mcg PO qDay
- >3 years: 25-75 mcg PO qDay
Nontoxic Goiter
Initial: 5 mcg PO qDay; may increase by 5-10 mcg q1-2Weeks
When reach 25 mcg PO qDay, may increase by 12.5 mcg or 25 mcg q1-2Weeks
Maintenance: 75 mcg PO qDay
5 mcg/day PO; may increase by 5 mcg/day q2Weeks
Interactions
Interaction Checker
No Results
Contraindicated
Serious - Use Alternative
Significant - Monitor Closely
Minor
Contraindicated (1)
- sodium iodide I-131
liothyronine will decrease the level or effect of sodium iodide I-131 by Other (see comment). Contraindicated. Use of thyroid products or iodine before and during treatment with sodium iodide I-131 decreases uptake of sodium iodide I-131 by the thyroid gland
Serious - Use Alternative (11)
- antithrombin alfa
liothyronine increases effects of antithrombin alfa by pharmacodynamic synergism. Avoid or Use Alternate Drug.
- antithrombin III
liothyronine increases effects of antithrombin III by pharmacodynamic synergism. Avoid or Use Alternate Drug.
- argatroban
liothyronine increases effects of argatroban by pharmacodynamic synergism. Avoid or Use Alternate Drug.
- bemiparin
liothyronine increases effects of bemiparin by pharmacodynamic synergism. Avoid or Use Alternate Drug.
- bivalirudin
liothyronine increases effects of bivalirudin by pharmacodynamic synergism. Avoid or Use Alternate Drug.
- dalteparin
liothyronine increases effects of dalteparin by pharmacodynamic synergism. Avoid or Use Alternate Drug.
- enoxaparin
liothyronine increases effects of enoxaparin by pharmacodynamic synergism. Avoid or Use Alternate Drug.
- fondaparinux
liothyronine increases effects of fondaparinux by pharmacodynamic synergism. Avoid or Use Alternate Drug.
- heparin
liothyronine increases effects of heparin by pharmacodynamic synergism. Avoid or Use Alternate Drug.
- phenindione
liothyronine increases effects of phenindione by pharmacodynamic synergism. Avoid or Use Alternate Drug.
- protamine
liothyronine increases effects of protamine by pharmacodynamic synergism. Avoid or Use Alternate Drug.
Monitor Closely (22)
- carbonyl iron
carbonyl iron decreases levels of liothyronine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
- cholestyramine
cholestyramine decreases levels of liothyronine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
- colesevelam
colesevelam will decrease the level or effect of liothyronine by Mechanism: inhibition of GI absorption. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Administer thyroid hormones at least 4 hr before colesevelam. Elevated thyroid-stimulating hormone (TSH) in patients receiving thyroid hormone.
- crofelemer
crofelemer increases levels of liothyronine by Other (see comment). Use Caution/Monitor. Comment: Crofelemer has the potential to inhibit transporters MRP2 and OATP1A2 at concentrations expected in the gut; unlikely to inhibit systemically because minimally absorbed.
- didanosine
didanosine will decrease the level or effect of liothyronine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Applies to didanosine chewable tablets and powder for oral solution; administer 2 hr before or several hours after didanosine oral solution or chewable tablet administration
- digoxin
liothyronine decreases effects of digoxin by unknown mechanism. Use Caution/Monitor.
- eluxadoline
eluxadoline increases levels of liothyronine by decreasing metabolism. Use Caution/Monitor. Eluxadoline may increase the systemic exposure of coadministered OATP1B1 substrates.
- ferric maltol
ferric maltol decreases levels of liothyronine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
- ferrous fumarate
ferrous fumarate decreases levels of liothyronine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
- ferrous gluconate
ferrous gluconate decreases levels of liothyronine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
- ferrous sulfate
ferrous sulfate decreases levels of liothyronine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
- insulin degludec
liothyronine decreases effects of insulin degludec by pharmacodynamic antagonism. Use Caution/Monitor. Thyroid hormones regulate carbohydrate metabolism, gluconeogenesis, and glycogen stores mobilization; dose of antidiabetic agents may need adjustment and increased frequency of glucose monitoring may be required.
- insulin degludec/insulin aspart
liothyronine decreases effects of insulin degludec/insulin aspart by pharmacodynamic antagonism. Use Caution/Monitor. Thyroid hormones regulate carbohydrate metabolism, gluconeogenesis, and glycogen stores mobilization; dose of antidiabetic agents may need adjustment and increased frequency of glucose monitoring may be required.
- insulin inhaled
liothyronine decreases effects of insulin inhaled by pharmacodynamic antagonism. Use Caution/Monitor. Thyroid hormones regulate carbohydrate metabolism, gluconeogenesis, and glycogen stores mobilization; dose of antidiabetic agents may need adjustment and increased frequency of glucose monitoring may be required.
- iron dextran complex
iron dextran complex decreases levels of liothyronine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
- iron sucrose
iron sucrose decreases levels of liothyronine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
- lanthanum carbonate
lanthanum carbonate decreases levels of liothyronine by cation binding in GI tract. Use Caution/Monitor. Administer oral thyroid products at least 2 hr before or after lanthanum. Interaction applies only to oral thyroid products only. .
- levonorgestrel oral/ethinylestradiol/ferrous bisglycinate
levonorgestrel oral/ethinylestradiol/ferrous bisglycinate will decrease the level or effect of liothyronine by unknown mechanism. Modify Therapy/Monitor Closely. The estrogen component of combined hormonal contraceptives (CHCs) may raise the serum concentrations of thyroxine-binding globulin. Women on thyroid hormone replacement therapy may need increased doses of thyroid hormone with use of CHCs.
- metformin
liothyronine decreases effects of metformin by pharmacodynamic antagonism. Use Caution/Monitor. Patient should be closely observed for loss of blood glucose control; when drugs are withdrawn from a patient receiving metformin, patient should be observed closely for hypoglycemia.
- polysaccharide iron
polysaccharide iron decreases levels of liothyronine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
- rose hips
rose hips decreases levels of liothyronine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.
- warfarin
liothyronine increases effects of warfarin by unspecified interaction mechanism. Use Caution/Monitor.
Minor (27)
- amobarbital
amobarbital decreases levels of liothyronine by increasing metabolism. Minor/Significance Unknown.
- butabarbital
butabarbital decreases levels of liothyronine by increasing metabolism. Minor/Significance Unknown.
- butalbital
butalbital decreases levels of liothyronine by increasing metabolism. Minor/Significance Unknown.
- carbamazepine
carbamazepine decreases levels of liothyronine by increasing metabolism. Minor/Significance Unknown.
- colestipol
colestipol decreases levels of liothyronine by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
- dexlansoprazole
dexlansoprazole decreases levels of liothyronine by increasing gastric pH. Applies only to oral form of both agents. Minor/Significance Unknown. Conflicting evidence regarding this interaction exists.
- eslicarbazepine acetate
eslicarbazepine acetate decreases levels of liothyronine by increasing metabolism. Minor/Significance Unknown.
- esomeprazole
esomeprazole decreases levels of liothyronine by increasing gastric pH. Applies only to oral form of both agents. Minor/Significance Unknown. Conflicting evidence regarding this interaction exists.
- ethotoin
ethotoin decreases levels of liothyronine by increasing metabolism. Minor/Significance Unknown.
ethotoin decreases levels of liothyronine by plasma protein binding competition. Minor/Significance Unknown. - fosphenytoin
fosphenytoin decreases levels of liothyronine by increasing metabolism. Minor/Significance Unknown.
fosphenytoin decreases levels of liothyronine by plasma protein binding competition. Minor/Significance Unknown. - furosemide
furosemide increases toxicity of liothyronine by Other (see comment). Minor/Significance Unknown. Comment: High doses (greater than 80 mg) of furosemide may inhibit binding of thyroid hormones to carrier proteins and result in transient increase in free thyroid hormones, followed by overall decrease in total thyroid hormone levels.
- glandular products
glandular products increases effects of liothyronine by pharmacodynamic synergism. Minor/Significance Unknown. Additive effects with thyroid glandular extract.
- guggul
guggul decreases effects of liothyronine by pharmacodynamic antagonism. Minor/Significance Unknown.
- lansoprazole
lansoprazole decreases levels of liothyronine by increasing gastric pH. Applies only to oral form of both agents. Minor/Significance Unknown. Conflicting evidence regarding this interaction exists.
- omeprazole
omeprazole decreases levels of liothyronine by increasing gastric pH. Applies only to oral form of both agents. Minor/Significance Unknown. Conflicting evidence regarding this interaction exists.
- oxcarbazepine
oxcarbazepine decreases levels of liothyronine by increasing metabolism. Minor/Significance Unknown.
- pantoprazole
pantoprazole decreases levels of liothyronine by increasing gastric pH. Applies only to oral form of both agents. Minor/Significance Unknown. Conflicting evidence regarding this interaction exists.
- pentobarbital
pentobarbital decreases levels of liothyronine by increasing metabolism. Minor/Significance Unknown.
- phenobarbital
phenobarbital decreases levels of liothyronine by increasing metabolism. Minor/Significance Unknown.
- phenytoin
phenytoin decreases levels of liothyronine by increasing metabolism. Minor/Significance Unknown.
phenytoin decreases levels of liothyronine by plasma protein binding competition. Minor/Significance Unknown. - piracetam
piracetam, liothyronine. Mechanism: unknown. Minor/Significance Unknown. Combination of piracetam and T3+T4 produced confusion, sleep disorder in single case.
- primidone
primidone decreases levels of liothyronine by increasing metabolism. Minor/Significance Unknown.
- rabeprazole
rabeprazole decreases levels of liothyronine by increasing gastric pH. Applies only to oral form of both agents. Minor/Significance Unknown. Conflicting evidence regarding this interaction exists.
- rifampin
rifampin decreases levels of liothyronine by increasing metabolism. Minor/Significance Unknown.
- secobarbital
secobarbital decreases levels of liothyronine by increasing metabolism. Minor/Significance Unknown.
- shepherd's purse
shepherd's purse decreases effects of liothyronine by unspecified interaction mechanism. Minor/Significance Unknown. Theoretical interaction.
- theophylline
liothyronine decreases levels of theophylline by increasing elimination. Minor/Significance Unknown.
Adverse Effects
1-10%
Tachycardia (3%)
Hypotension (2%)
Myocardial infarction (2%)
Cardiopulmonary arrest (2%)
<1%
Congestive heart failure
Hypertension
Twitching
Phlebitis
Angina
Fever
Warnings
Black Box Warnings
Thyroid hormones, 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.
Contraindications
Hypersensitivity to thyroid hormone
Acute MI uncomplicated by hypothyroidism, thyrotoxicosis, untreated adrenal insufficiency
Treatment of obesity or infertility
Cautions
Caution in angina, cardiovascular disease, hypopituitarism, DM
May use judiciously in acute MI caused/complicated by hypothyroidism
Perform periodic assessment of thyroid status when using as thyroid replacement
Myxedematous patients are very sensitive to thyroid hormone; start at very low dose
Pregnancy & Lactation
Pregnancy category: A
Lactation: Excreted into breast milk; use caution
Pregnancy Categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk. C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done. D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk. X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist. NA: Information not available.Pharmacology
Mechanism of Action
A synthetic form of natural T3 hormone with same actions as natural product; thyroid hormone raises basal metabolic rate, increases utilization and mobilization of glycogen store, and promotes gluconeogenesis
Absorption
95% absorption
Onset: 2-4 hr
Duration: Several days (hypothyroidism)
Peak plasma time: PO: 1-2 hr
Max response: 2-3 days
Distribution
Protein bound: 99.7%, but not firmly
Metabolism
Hepatic, to deiodinated and conjugated metabolites
Elimination
Half-life: 2.5 days
Excretion: Urine, feces
Administration
IV Administration
Administer q4hr; no more than 12 hr apart
Images
| BRAND | FORM. | UNIT PRICE | PILL IMAGE |
|---|---|---|---|
| Triostat intravenous - | 10 mcg/mL vial |  | |
| Triostat intravenous - | 10 mcg/mL vial |  | |
| Cytomel oral - | 50 mcg tablet |  | |
| Cytomel oral - | 5 mcg tablet |  | |
| Cytomel oral - | 25 mcg tablet |  | |
| liothyronine oral - | 5 mcg tablet |  | |
| liothyronine oral - | 50 mcg tablet |  | |
| liothyronine oral - | 5 mcg tablet |  | |
| liothyronine oral - | 50 mcg tablet |  | |
| liothyronine oral - | 25 mcg tablet |  | |
| liothyronine oral - | 50 mcg tablet |  | |
| liothyronine oral - | 25 mcg tablet |  | |
| liothyronine oral - | 5 mcg tablet |  | |
| liothyronine oral - | 50 mcg tablet | | |
| liothyronine oral - | 25 mcg tablet | | |
| liothyronine oral - | 5 mcg tablet | | |
| liothyronine intravenous - | 10 mcg/mL vial |  |
Copyright © 2010 First DataBank, Inc.
Patient Handout
liothyronine oral
LIOTHYRONINE - ORAL
(LYE-oh-THYE-roe-neen)
COMMON BRAND NAME(S): Cytomel
WARNING: This medication should not be used for weight loss. Normal doses of this medication will not work for weight loss, and large doses may cause serious, possibly fatal side effects, especially when taken with diet pills.
USES: Liothyronine is used to treat an underactive thyroid (hypothyroidism). It replaces or provides more thyroid hormone, which is normally made by the thyroid gland. Liothyronine is a man-made form of thyroid hormone. Low thyroid hormone levels can occur naturally or when the thyroid gland is injured by radiation/medications or removed by surgery. Having enough thyroid hormone helps you stay healthy. For children, having enough thyroid hormone helps them grow and learn normally.This medication is also used to treat other types of thyroid problems (such as certain types of goiters, thyroid cancer). It can also be used to test for certain types of thyroid disease.This medication should not be used to treat infertility unless it is caused by low thyroid hormone levels.
HOW TO USE: Take this medication by mouth with or without food as directed by your doctor, usually once daily. It is best to take it at the same time each day so your thyroid hormone level is kept at a constant level.Take this medication regularly to get the most benefit from it. Do not stop taking it without first talking with your doctor. Thyroid replacement treatment is usually taken for life.The dosage is based on your medical condition, age, lab test results, and response to treatment.Certain medications can decrease the absorption of liothyronine. Examples include products that contain aluminum or magnesium, antacids, sucralfate, calcium supplements, iron, bile acid-binding resins (such as cholestyramine, colestipol, colesevelam), simethicone, sevelamer, sodium polystyrene sulfonate, among others. If you take any of these medications, take them at least 4 hours before or after liothyronine. If you take lanthanum, take it at least 2 hours before or after liothyronine.Symptoms of low thyroid hormone levels include tiredness, muscle aches, constipation, dry skin, weight gain, slow heartbeat, or sensitivity to cold. You may see an improvement in these symptoms within a few days. Tell your doctor if you do not get better or if you get worse.
SIDE EFFECTS: Temporary hair loss may occur during the first few months of starting this drug, especially in children. If this effect lasts or gets worse, tell your doctor or pharmacist promptly.Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.Though unlikely, it is possible to have too much thyroid hormone. Tell your doctor right away if you have symptoms of too much thyroid hormone, including: headache, mental/mood changes (such as irritability, nervousness), increased sweating, sensitivity to heat, diarrhea, menstrual changes.Get medical help right away if you have any very serious symptoms of too much thyroid hormone, including: chest pain, fast/pounding/irregular heartbeat, swelling ankles/feet, trouble breathing, unusual tiredness.A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.In the US -Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.
PRECAUTIONS: Before taking liothyronine, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.Before using this medication, tell your doctor or pharmacist your medical history, especially of: decreased adrenal gland function, heart disease (such as chest pain, heart failure, irregular heartbeat, heart attack), high blood pressure, diabetes, water diabetes (diabetes insipidus).Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).Current information shows that this drug may be used during pregnancy. Tell your doctor if you are pregnant because your doctor may need to change your dose.Liothyronine passes into breast milk but is unlikely to harm a nursing infant. Consult your doctor before breast-feeding.
DRUG INTERACTIONS: See also How to Use section.Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.Some products that may interact with this drug include: "blood thinners" (such as warfarin).
OVERDOSE: If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center. Symptoms of overdose may include: fast/irregular heartbeat, chest pain, trouble breathing, confusion.
NOTES: Do not share this medication with others.Lab and/or medical tests (such as thyroid function tests) should be done while you are taking this medication. Keep all medical and lab appointments.
MISSED DOSE: If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up unless your doctor instructs you to do so. Call your doctor if you miss 2 or more doses in a row. Ask your doctor ahead of time what to do about a missed dose and follow your doctor's specific directions.
STORAGE: Store at room temperature away from light and moisture. Do not store in the bathroom. Keep all medications away from children and pets.Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.
Information last revised August 2021. Copyright(c) 2022 First Databank, Inc.
IMPORTANT: HOW TO USE THIS INFORMATION: This is a summary and does NOT have all possible information about this product. This information does not assure that this product is safe, effective, or appropriate for you. This information is not individual medical advice and does not substitute for the advice of your health care professional. Always ask your health care professional for complete information about this product and your specific health needs.
Formulary
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