Liothyronine (L-triiodothyronine)

Liothyronine Brand Names- Cytomel | Triostat

What is Liothyronine

Liothyronine (L-triiodothyronine) is a synthetic sodium salt of the endogenous thyroid hormone triiodothyronine (T3).

The oral tablet is indicated for use as replacement or supplemental therapy in the treatment of hypothyroidism of any etiology, except transient hypothyroidism during the recovery phase of subacute thyroiditis, including congenital hypothyroidism (cretinism).

The replacement of thyroid hormone using levothyroxine (T4) alone is sufficient in most individuals with hypothyroidism and is the preferred replacement therapy for routine use in patients of all ages.

However, in select patients, such as patients who continue to have symptoms despite euthyroid status after stabilization of a dose for T4 replacement, partial substitution of T3 for T4 may be beneficial.

Liothyronine is also used as a diagnostic agent in TSH suppression tests as an aid in detecting hyperthyroidism, and as an adjunct agent in the treatment of well-differentiated thyroid cancer; however, levothyroxine is usually the preferred agent for these purposes.

Liothyronine injection is most commonly used in the treatment of myxedema coma.

Due to the fast onset of action of liothyronine, combination therapy with levothyroxine and liothyronine may be recommended for selected patients in the treatment of myxedema coma, as T4 to T3 conversion is impaired in some patients.

Liothyronine first received FDA-approval for clinical use in 1954.

Indications

1. cretinism
2. hyperthyroidism diagnosis
3. hypothyroidism
4. myxedema coma
5. organ preservation
6. thyroid cancer

Thyroid Products Equivalent Oral Dosages; listings are estimates only:

Preparation-dosage equivalents-(T₄: T₃ ratio)

Levothyroxine: 100 mcg -(1:0)

Liothyronine: 25 mcg -(0:1)

Levothyroxine; Liothyronine (e.g., Liotrix-1): 50 to 60 mcg/12.5 to 15 mcg -(4:1)

Thyroid USP: 60 mg (1 grain) -(2 to 5:1)

For the treatment of hypothyroidism of any etiology, except during the recovery phase of subacute thyroiditis; used as a replacement in primary (thyroidal), secondary (pituitary), tertiary (hypothalamic), congenital (cretinism), or acquired hypothyroidism

Side Effects

1. abdominal pain
2. alopecia
3. amenorrhea
4. angina
5. angioedema
6. anorexia
7. anxiety
8. appetite stimulation
9. arrhythmia exacerbation
10. arthralgia
11. atrial fibrillation
12. cardiac arrest
13. craniosynostosis
14. diarrhea
15. dyspnea
16. elevated hepatic enzymes
17. emotional lability
18. epiphyseal closure
19. fatigue
20. fever
21. flushing
22. growth inhibition
23. headache
24. heart failure
25. heat intolerance
26. hyperactivity
27. hyperhidrosis
28. hypertension
29. hyperthyroidism
30. hypotension
31. increased intracranial pressure
32. infertility
33. insomnia
34. irritability
35. muscle cramps
36. myocardial infarction
37. nausea
38. osteopenia
39. osteoporosis
40. palpitations
41. peripheral edema
42. phlebitis
43. pruritus
44. pseudotumor cerebri
45. rash
46. serum sickness
47. sinus tachycardia
48. thyrotoxicosis
49. tremor
50. urticaria
51. vomiting
52. weakness
53. weight loss
54. wheezing

Monitoring Parameters

• blood pressure
• growth rate
• heart rate
• thyroid function tests (TFTs)
• total T3 (triiodothyronine)
• weight

Contraindications

• acute myocardial infarction
• adrenal insufficiency
• angina
• breast-feeding
• cardiac arrhythmias
• cardiac disease
• coronary artery disease
• diabetes mellitus
• epiphyseal closure
• geriatric
• heart failure
• hypertension
• hyperthyroidism
• hyponatremia
• hypopituitarism
• hypothermia
• infertility
• intramuscular administration
• myocardial infarction
• myxedema
• obesity treatment
• osteopenia
• pregnancy
• renal failure
• renal impairment
• subcutaneous administration
• surgery
• thyrotoxicosis
• water intoxication

Interactions

• Acarbose
• Acetaminophen; Butalbital
• Acetaminophen; Butalbital; Caffeine
• Acetaminophen; Butalbital; Caffeine; Codeine
• Acetohexamide
• Albiglutide
• Alogliptin
• Alogliptin; Metformin
• Alogliptin; Pioglitazone
• Alpha-glucosidase Inhibitors
• Aluminum Hydroxide
• Aluminum Hydroxide; Magnesium Carbonate
• Aluminum Hydroxide; Magnesium Hydroxide
• Aluminum Hydroxide; Magnesium Hydroxide; Simethicone
• Aluminum Hydroxide; Magnesium Trisilicate
• Amiodarone
• Amobarbital
• Amoxapine
• Amoxicillin; Clarithromycin; Lansoprazole
• Amoxicillin; Clarithromycin; Omeprazole
• Asparaginase Erwinia chrysanthemi
• Aspirin, ASA; Butalbital; Caffeine
• Aspirin, ASA; Butalbital; Caffeine; Codeine
• Aspirin, ASA; Omeprazole
• Atropine; Hyoscyamine; Phenobarbital; Scopolamine
• Azelastine; Fluticasone
• Barbiturates
• Beclomethasone
• Belladonna Alkaloids; Ergotamine; Phenobarbital
• Beta-agonists
• Beta-blockers
• Betamethasone
• Budesonide
• Budesonide; Formoterol
• Butabarbital
• Calcium
• Calcium Acetate
• Calcium Carbonate
• Calcium Carbonate; Magnesium Hydroxide
• Calcium Carbonate; Risedronate
• Calcium Carbonate; Simethicone
• Calcium Chloride
• Calcium Gluconate
• Calcium; Vitamin D
• Canagliflozin
• Canagliflozin; Metformin
• Carbamazepine
• Chlorpropamide
• Cholestyramine
• Chromium
• Ciclesonide
• Cocaine
• Colesevelam
• Colestipol
• Corticosteroids
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• Dapagliflozin; Metformin
• Dapagliflozin; Saxagliptin
• Deflazacort
• Dexamethasone
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• Didanosine, ddI
• Digoxin
• Dulaglutide
• Empagliflozin
• Empagliflozin; Linagliptin
• Empagliflozin; Linagliptin; Metformin
• Empagliflozin; Metformin
• enteral feedings
• Ertugliflozin; Metformin
• Ertugliflozin; Sitagliptin
• Esomeprazole
• Esomeprazole; Naproxen
• Estrogens
• Ethinyl Estradiol; Norethindrone Acetate; Ferrous fumarate
• Ethinyl Estradiol; Norethindrone; Ferrous fumarate
• Exenatide
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• Fluticasone
• Fluticasone; Salmeterol
• Fluticasone; Umeclidinium; Vilanterol
• Fluticasone; Vilanterol
• food
• Formoterol; Mometasone
• Furosemide
• Glimepiride
• Glimepiride; Pioglitazone
• Glimepiride; Rosiglitazone
• Glipizide
• Glipizide; Metformin
• Glyburide
• Glyburide; Metformin
• Hetastarch; Dextrose; Electrolytes
• Hydantoins
• Hydrocortisone
• Imatinib
• Indinavir
• Insulin Degludec; Liraglutide
• Insulin Glargine; Lixisenatide
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• Iodine; Potassium Iodide, KI
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• Iron
• Iron Salts
• Iron Sucrose, Sucroferric Oxyhydroxide
• Isoniazid, INH; Pyrazinamide, PZA; Rifampin
• Isoniazid, INH; Rifampin
• Isosulfan Blue
• Ketamine
• L-Asparaginase Escherichia coli
• Lansoprazole
• Lansoprazole; Naproxen
• Lanthanum Carbonate
• Linagliptin
• Linagliptin; Metformin
• Liraglutide
• Lithium
• Lixisenatide
• Magnesium
• Maprotiline
• Meglitinides
• Mephobarbital
• Metformin
• Metformin; Pioglitazone
• Metformin; Repaglinide
• Metformin; Rosiglitazone
• Metformin; Saxagliptin
• Metformin; Sitagliptin
• Methimazole
• Methohexital
• Methylprednisolone
• Miglitol
• Mometasone
• Non-Ionic Contrast Media
• Omeprazole
• Omeprazole; Amoxicillin; Rifabutin
• Omeprazole; Sodium Bicarbonate
• Orlistat
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• Polycarbophil
• Polysaccharide-Iron Complex
• Potassium Iodide, KI
• Pramlintide
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• Primidone
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• Rabeprazole
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• Rosiglitazone
• Saxagliptin
• Secobarbital
• Semaglutide
• Sevelamer
• Simethicone
• Simvastatin; Sitagliptin
• Sitagliptin
• Sodium Ferric Gluconate Complex; ferric pyrophosphate citrate
• Sodium Iodide
• Sodium Polystyrene Sulfonate
• Somatropin, rh-GH
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• Sulfonylureas
• Sympathomimetics
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• Theophylline, Aminophylline
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