Description

Simple

A medication used to replace missing thyroid hormone, to treat goiter (a large thyroid gland), and to test the thyroid for different conditions.

Clinical

A thyroid hormone replacement therapy used to treat hypothyroidism, to suppress TSH, and to help in the diagnosis of hyperthyroidism.

Overview

Liothyronine is a thyroidal hormone T3 which is normally produced by the thyroid gland in a ratio 4:1 when compared with T4: T3. Liothyronine is the active form of thyroxine which is composed in a basic chemical structure by a tyrosine with bound iodine.[3] The exogenous liothyronine product was developed by King Pharmaceuticals and FDA approved in 1956.[8]

Pharmacology

Indication

Liothyronine is officially approved for the following indications:

- Replacement therapy in primary (thyroidal), secondary (pituitary) and tertiary (hypothalamic) congenital or acquired hypothyroidism.

- As an adjunct therapy to surgery and radioiodine in the management of thyroid cancer.

-... Read more

Pharmacodynamic

In hormonal replacement, liothyronine is more potent and present a faster action when compared to levothyroxine but the time of action is significantly shorter. The type of treatment needs to be well evaluated as the fast correction of thyroid hormones in certain diseases presents additional risks s... Read more

Mechanism of action

Liothyronine replaces endogenous thyroid hormone and then exerts its physiologic effects by controlling DNA transcription and protein synthesis. This effect on DNA is obtained by the binding of liothyronine to the thyroid receptors attached to DNA. Exogenous liothyronine exerts all the normal effect... Read more

Absorption

Thyroid hormones are well absorbed orally. From these hormones, liothyronine is almost completely absorbed and it does not present changes in the absorption rate due to concomitant administration of food.[ Read more

Protein binding

Liothyronine presents a very large binding to plasma proteins and around 99.7% of the administered dose can be found bound.[4 Read more

Volume of distribution

The reported volume of distribution of liothyronine is reported to be of 0.1-0.2 L/kg.[7]

Clearance

There are no reports obtaining this value specifically.

Half life

The half-life of liothyronine is reported to be between 1 and 2 days.[4]

Route of elimination

The main elimination of thyroid hormones is known to be done via the kidneys from which less than 2.5% of the excreted drug is represented by the unchanged drug. This elimination route is reduced with age. A portion of the metabolic products of liothyronine is excreted to the bile and gut where they... Read more

Toxicity

The reported oral LD50 of liothyronine in the rat is higher than 4540 mg/kg. When overdosage is registered, symptoms of hyperthyroidism are reported as well as confusion, disorientation, cerebral embolism, seizure, shock, coma, and death. The symptoms of overdose can be presented immediately or seve... Read more

Adverse Effects

Contraindications

  • Regions: US
  • Patient Conditions:
      • Name: Untreated thyrotoxicosis
      • Drugbank Id: DBCOND0107550
  • Regions: US
  • Patient Conditions:
      • Name: Uncorrected adrenal cortical insufficiency
      • Drugbank Id: DBCOND0107549

Food Interactions

  • Take with or without food.

Interactions

Type in a drug name to check for interaction with Liothyronine
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  • Paracetamol(acetaminophen)
  • Paxil(paroxetine)
  • Pamelor(nortriptyline)
  • Panadol(acetaminophen)
  • Patanol(olopatadine ophthalmic)
  • Pataday(olopatadine ophthalmic)
  • Parnate(tranylcypromine)
  • Pazeo(olopatadine ophthalmic)
(R)-warfarin
The risk or severity of bleeding can be increased when Liothyronine is combined with (R)-warfarin.
(S)-Warfarin
The risk or severity of bleeding can be increased when Liothyronine is combined with (S)-Warfarin.
2,4-thiazolidinedione
The therapeutic efficacy of 2,4-thiazolidinedione can be decreased when used in combination with Liothyronine.
2,5-Dimethoxy-4-ethylamphetamine
The risk or severity of adverse effects can be increased when 2,5-Dimethoxy-4-ethylamphetamine is combined with Liothyronine.
2,5-Dimethoxy-4-ethylthioamphetamine
The risk or severity of adverse effects can be increased when 2,5-Dimethoxy-4-ethylthioamphetamine is combined with Liothyronine.
3-[4-(1-formylpiperazin-4-yl)-benzylidenyl]-2-indolinone
The therapeutic efficacy of Liothyronine can be decreased when used in combination with 3-[4-(1-formylpiperazin-4-yl)-benzylidenyl]-2-indolinone.
3-isobutyl-1-methyl-7H-xanthine
Liothyronine may increase the excretion rate of 3-isobutyl-1-methyl-7H-xanthine which could result in a lower serum level and potentially a reduction in efficacy.
4-Bromo-2,5-dimethoxyamphetamine
The risk or severity of adverse effects can be increased when 4-Bromo-2,5-dimethoxyamphetamine is combined with Liothyronine.
4-hydroxycoumarin
The risk or severity of bleeding can be increased when Liothyronine is combined with 4-hydroxycoumarin.
5-fluorouridine
The therapeutic efficacy of Liothyronine can be decreased when used in combination with 5-fluorouridine.
6-O-benzylguanine
Liothyronine may increase the excretion rate of 6-O-benzylguanine which could result in a lower serum level and potentially a reduction in efficacy.
7-Deazaguanine
Liothyronine may increase the excretion rate of 7-Deazaguanine which could result in a lower serum level and potentially a reduction in efficacy.
7,9-Dimethylguanine
Liothyronine may increase the excretion rate of 7,9-Dimethylguanine which could result in a lower serum level and potentially a reduction in efficacy.
8-azaguanine
Liothyronine may increase the excretion rate of 8-azaguanine which could result in a lower serum level and potentially a reduction in efficacy.
8-chlorotheophylline
Liothyronine may increase the excretion rate of 8-chlorotheophylline which could result in a lower serum level and potentially a reduction in efficacy.
9-Deazaguanine
Liothyronine may increase the excretion rate of 9-Deazaguanine which could result in a lower serum level and potentially a reduction in efficacy.
9-Methylguanine
Liothyronine may increase the excretion rate of 9-Methylguanine which could result in a lower serum level and potentially a reduction in efficacy.
Abacavir
Liothyronine may decrease the excretion rate of Abacavir which could result in a higher serum level.
Acalabrutinib
The therapeutic efficacy of Liothyronine can be decreased when used in combination with Acalabrutinib.
Acarbose
The therapeutic efficacy of Acarbose can be decreased when used in combination with Liothyronine.
9 References
  1. 1 . Jonklaas J, Burman KD, Wang H, Latham KR: Single-dose T3 administration: kinetics and effects on biochemical and physiological parameters. Ther Drug Monit. 2015 Feb;37(1):110-8. doi: 10.1097/FTD.0000000000000113.PubMed: 24977379
  2. 2 . Sullivan K. (2009). Nurse's drug handbook (8th ed.). Jones and Bartlett Publishers, LLC.
  3. 3 . Upfal J. (2007). The Australian Drug Guide (7th ed.). National Library of Australia.
  4. 4 . Harrold M. and Zavod R. (2013). Basic Concepts in Medicinal Chemistry. American Society of Health-System Pharmacists.
  5. 5 . Scott-Moncrieff C. (2015). Canine and feline endocrinology (4th ed.). Elsevier.
  6. 6 . Kumar P. (2017). Pharmacology and therapeutics for dentistry (7th ed.). Mosby.
  7. 7 . Ashley C. and Dunleavy A. (2014). The renal drug handbook. Caroline Ashley and Aileen Dunleavy.
  8. 8 . FDA approvals Link
  9. 9 . FDA reports Link