In the Body, What Is the Role of Thyroxine?

Thyroxine is a product of cells and is a gray-white needle-like crystal. Mp231-233 ° C (decomposed). Soluble in alkali hydroxide or carbonate solution, insoluble in water, ethanol and other organic solvents, but soluble in ethanol solution of inorganic acid or alkali.

1. Molar refractive index: 125.44

2. Molar volume (cm3 / mol): 294.7

3. Isotonic specific volume (90.2K): 880.4

4. Surface tension (dyne / cm): 79.6

5. Polarizability (10-24cm3): 49.73 ^[3]

1. Hydrophobic parameter calculation reference value (XlogP): 2.4

2.Number of hydrogen-bonded donors: 3

3.Number of hydrogen bond acceptors: 5

4.Number of rotatable chemical bonds: 5

5.Number of tautomers: 2

6. Topological molecular polar surface area 92.8

7.Number of heavy atoms: 24

8.Surface charge: 0

9.Complexity: 420

10.Number of isotope atoms: 0

11. Determine the number of atomic stereocenters: 0

12. Uncertain number of atomic stereocenters: 1

13. Determine the number of chemical bond stereocenters: 0

14. Uncertain number of chemical bond stereocenters: 0

15. Number of covalent bond units: 1 ^[3]

That is tetraiodothyronine. There are DL, L, and D types. Type L is white crystal. Decomposes at 235 ~ 236 ° C. Optical rotation -4.4 ° (3% at 0.13mol / L NaOH in 70% ethanol). Form D is a crystal and decomposes at 237 ° C; Form DL is a needle-like crystal and decomposes at 231 to 233 ° C. Soluble in alkaline solution, insoluble in water, ethanol and

Thyroxine is formed through six processes: synthesis, storage, iodination, reabsorption, decomposition and release:

1,

1. Promote the metabolism of substances and energy in the body, which is mainly to promote the oxidative decomposition of energy substances in the body, namely sugars, proteins and fats, so that oxygen consumption is increased and energy is released at the same time. ^[6]

This product is a thyroid hormone medicine. Can promote metabolism, maintain normal growth and development, and improve body sensitivity. It is mainly used in the treatment of cretinism, myxedema and other hypothyroidism. ^[5]

Oral absorption is only 40%, and the effect is slow and long-lasting (appears after 7 to 10 days, and the effect disappears after 4 to 5 weeks. Repeated medication is easy to accumulate poisoning. ^[4]

(1) Cirrhosis ^[7]

Overdose can cause hyperthyroidism, angina pectoris and myocardial infarction can occur in the elderly and heart disease. Soothing can counteract its effects. It can also be seen that bone decalcification causes osteoporosis, increased calcium and phosphorus excretion, and reduced neuromuscular excitability. ^[7]

Sodium thyroxine, 0.1mg is equivalent to 60mg of thyroid tablets (thyroid tablets are crude dry products of domestic thyroid, mainly containing thyroxine, but also a small amount of T ₃ ), oral: 0.1 0.2mg / d, intravenous injection: 0.3 0.5mg / d . ^[5]

Poisoning is usually caused by taking too long, taking too much or increasing the dose too quickly. ^[8]

Clinical manifestations of thyroxine

1. Hypermetabolism performance ^[8]

Fear of heat, sweating, palpitations, insomnia, agitation, increased appetite, weight loss, etc.

2. Mental and nervous system ^[8]

Nervous or mental disorders; tremor of hands, eyelids and / or tongue.

3. The musculoskeletal system ^[8]

May have myalgia, muscle fibrillation, calf painful spasm, occasional muscle weakness or flaccid paralysis, and even acute respiratory muscle paralysis.

4. Cardiovascular system ^[8]

Tachycardia, increased systolic blood pressure, increased pulse pressure, enlarged heart, apical first heart sound hyperthyroidism, smell of systolic or diastolic murmur and pre-systolic, paroxysmal or persistent atrial fibrillation, atrioventricular block Arrhythmia.

5. Endocrine disorders ^[8]

Women may have amenorrhea, amenorrhea, or menstruation earlier, and their menstrual flow increases; men may have impotence, with occasional breast development.

6. Few patients have liver damage ^[8]

Elevated aminotransferase or jaundice.

Thyroid hormone laboratory test

Examination of vomitus, gastric juice, urine, and blood can prove poison. ^[8]

Thyroxine diagnosis

The main points of diagnosis of thyroxine poisoning are: ^[8]

1. Medical history has a history of application of thyroid hormone preparations.

2. Clinical manifestations

(1) In mild cases, fever, sweating, urination, headache, irritability, hand tremor, insomnia, fear and weight loss may occur.

(2) In severe cases, there are nausea, vomiting, diarrhea, high fever, weight loss, myalgia, muscle fibrillation, calf pain spasm, neurosensitivity or mental disorder; occasionally muscle weakness or relaxation paralysis, and even acute respiratory muscle paralysis.

(3) Endocrine disorders may also occur. A few patients have cardiac changes such as liver damage, enlarged heart, angina, heart failure or arrhythmia.

3. Drug analysis of vomit, gastric juice, urine, blood and poisons.

Thyroxine measures

The main points of treatment for thyroxine poisoning are: ^[8]

Remove poison

When symptoms of poisoning occur, immediately stop medication, induce vomiting, lavage the stomach with a medicinal charcoal suspension or a 1: 5 000 potassium permanganate solution, and use diarrhea to relieve diarrhea.

2. Symptomatic treatment and supportive therapy

(1) Supplement enough energy and vitamins to maintain water and electrolyte balance.

(2) Give sedatives, physical cooling and oxygen therapy.

(3) When the symptoms of hyperthyroidism appear, antithyroid hormones can be used, and the dose of thyroid tablets can be adjusted under the monitoring of T ₃ and T ₄ levels.

(4) Patients with elevated basal metabolic rate and mild symptoms without heart failure may be given beta blockers such as propranolol (propranolol).

(5) Those with heart failure may use digitalis as appropriate.

(6) When angina pectoris appears, the drug should be discontinued immediately, and -blockers (such as propranolol and betaxelol) should be used to counteract it.

(7) When atrial fibrillation occurs, ventricular rate should be actively controlled to restore sinus heart rate.

(8) In case of myocardial infarction or cardiac arrest, appropriate medical emergency treatment should be given.

(9) For severe poisoning reactions, hydrocortisone 200-300mg / d can be applied.

(10) Handle other complications, pay attention to protect liver and kidney function and prevent infection.

(11) Severe dialysis treatment or plasma exchange treatment. ^[4]