Pharmacodynamics and pharmacokinetics
Pharmacodynamics
Is a provitamin D3 . Its structure is similar to vitamin D2 . With a decrease in the function of the parathyroid glands, it increases the absorption of calcium in the intestine, enhances its transport from bone tissue, which leads to an increase in the level of calcium in the blood. Reduces the activity of alkaline phosphatase , prevents the development of osteoporosis . Has a weak antirachitic effect.
The drug is used for a long time without developing an overdose or addiction. The action appears quickly (from several days to 1-2 weeks), less long-lasting than that of vitamin D , therefore the risk of accumulation and development of hypercalcemia . At the end of the course of treatment, the effect lasts up to 9 weeks. Toxic effects appear at a dose of 25 mg per day and are manifested by hypercalcemia .
Pharmacokinetics
Rapidly absorbed in the small intestine. Binds to alpha globulins . Deposited in adipose tissue and liver. Metabolized in the liver. Excreted in bile and urine.
Dihydrotachysterol drops for oral administration in oil 1 mg/ml 10 ml
Dihydrotachysterol drops for oral administration in oil 1 mg/ml 10 ml N 1
Release form
Drops for oral administration
Compound
- 1 bottle contains:
- Active substance: dihydrotachysterol - 1 mg;
- Excipients: refined deodorized sunflower oil or refined deodorized soybean oil up to 1 ml.
Package
In bottles of 10, 15, 20 or 30 ml.
pharmachologic effect
Dihydrotachysterol is a drug that regulates metabolic processes. Regulator of calcium and phosphorus metabolism. Dihydrotachysterol increases the absorption of calcium in the intestine, thereby increasing its level in the blood. The drug also increases the excretion of inorganic phosphorus by the kidneys. Dihydrotachysterol can be used for long periods of time without developing overdose or tolerance effects.
The effect of the drug appears faster at the beginning of treatment and less long after the end of the course than that of vitamin D, thereby reducing the risk of accumulation of the drug in the body and the development of hypercalcemia. Dihydrotachysterol can exhibit toxic effects at doses of about 25 mg per day, resulting in symptoms of hypercalcemia. Does not cause addiction.
Dihydrotachysterol, indications for use
Hypoparathyroidism (idiopathic and postoperative), pseudohypoparathyroidism, tetany (muscle cramps caused by hypocalcemia), bone diseases caused by vitamin D deficiency.
Contraindications
Hypercalcemia, hypervitaminosis D, hypersensitivity to dihydrotachysterol and other vitamin D preparations.
Directions for use and doses
When taken orally, the daily dose is 0.25-1.5 mg. The frequency of use depends on the indications and concentrations of calcium in the blood and urine.
Side effects
From the digestive system: anorexia, nausea, vomiting, diarrhea; when used in high doses - biliary dyskinesia.
From the cardiovascular system: palpitations; rarely - heart rhythm disturbances.
Metabolism: thirst, tissue calcification.
From the urinary system: with long-term therapy - impaired renal function.
Other: pale skin, headache.
special instructions
Use with caution in patients with urolithiasis.
Concomitant use with other D vitamins, calcium supplements, and parathyroid drugs is not recommended.
Dihydrotachysterol should not be used in patients with allergic reactions to nuts (including groundnuts).
When used during thyroid hormone replacement therapy, adjustment of the dosage regimen of dihydrotachysterol may be required.
Drug interactions
When taking dihydrotachysterol simultaneously with vitamin D, as well as with drugs and nutritional supplements containing calcium, hypercalcemia may develop. When taking dihydrotachysterol simultaneously with thiazide diuretics and rifampicin, hypercalcemia may occur. Dihydrotachysterol enhances the effect of cardiac glycosides and calcium antagonists. When taking cardiac glycosides or calcium antagonists with dihydrotachysterol, the dose of the latter may be reduced. Barbiturates (phenobarbital), antiepileptic drugs [phenytoin (diphenin), carbamazepine (finlepsin), primidone (hexamidine)], anion exchange resins (colestyramine, colestipol) and petroleum jelly weaken the pharmacological effect of dihydrotachysterol. If treatment with thyroxine is carried out simultaneously while taking dihydrotachysterol, then after its withdrawal hypercalcemia may develop.
Storage conditions
In a place protected from light, at a temperature of 0–15 °C.
Best before date
2.5 years
Contraindications
- increased sensitivity;
- hypercalcemia;
- tetany with hyperventilation ;
- hypervitaminosis D;
- pregnancy;
- lactation;
- decompensated heart diseases.
It is prescribed with caution for kidney stones , atherosclerosis , hyperphosphatemia , pulmonary tuberculosis , renal failure , granulomatosis , in children and the elderly.
Dihydrotachysterol, instructions for use (Method and dosage)
Take orally after meals. Dihydrotachysterol drops are dosed with an eye pipette or using a dropper plug. There are 33 drops in 1 ml, one drop is 0.03 mg of dihydrotachysterol . The dose depends on the level of calcium and phosphorus, and the condition of the patient.
The daily dose is 0.5 - 1.5 mg, which corresponds to 17-50 drops taken daily. After a week, with positive changes (judged by the level of calcium and phosphorus), they switch to maintenance treatment of 17-50 drops per day, but take it from one to three times a week. Treatment takes a long period from 3 months to a year. If calcium supplements are additionally prescribed, smaller doses of dihydrotachysterol .
For tetany, 0.75-2.5 mg per day is prescribed for 3 days in a row, then the dose is reduced to 0.25-0.5 mg and taken for another 3 days. The maintenance dose is 0.25 mg once a week.
For renal osteodystrophy, 0.1-0.25 mg per day is prescribed, with a transition to a maintenance dose of 0.2-0.75 mg. During treatment, the level of calcium and phosphorus in the blood must be monitored once or twice a month at the beginning of treatment, then once a quarter. Long-term hypercalcemia leads to the development of urolithiasis . Additional preparations containing calcium and vitamin D are used with extreme caution for the same reason.
Dihydrotachysterol
Treatment should be carried out under the control of Ca2+ and phosphorus levels in the blood (before treatment, 5-7 days from the start of treatment and then 1-2 times a month).
It is recommended to follow a diet high in Ca2+ and low in phosphorus.
When prescribed during pregnancy, the development of premature ossification in the fetus is possible.
The effect of the drug can last up to a month after its discontinuation.
1 mg of the drug is equivalent to 3 mg (120 thousand IU) of ergocalciferol.
In high doses it has a teratogenic effect.
In renal osteodystrophy with hyperphosphatemia, there is a high risk of metastatic calcification, so vitamin D is prescribed only when the concentration of phosphates in the blood is normalized.
Due to the short T1/2, overdose symptoms can be corrected more easily than when taking vitamin D analogues with a long T1/2.
Since the drug has a narrow therapeutic range, the blood concentrations of Ca2+, phosphates, creatinine, urea nitrogen, and alkaline phosphatase activity should be determined first once a week, then periodically throughout the entire period of taking the drug in therapeutic doses. The Ca2+/creatinine index is recommended to be determined every 1-3 months until the patient’s condition is stabilized. The concentration of Ca2+ in the blood should not exceed 8.8-10.3 mg/100 ml. The product of Ca2+ concentration and phosphate concentration (Ca x P) should not exceed 60 mg/dl.
Every 3-6 months (more often in case of familial hypophosphatemia, hypoparathyroidism), an X-ray examination of the skeletal system should be performed.
It should be borne in mind that sensitivity to vitamin D varies from patient to patient, and even therapeutic doses can cause hypervitaminosis.
To prevent hypovitaminosis D, a balanced diet is most preferable.
Breastfed newborns, especially those of mothers with dark skin and/or insufficient sun exposure, are at high risk of vitamin D deficiency. Newborns' sensitivity to vitamin D varies, and some may be sensitive to even very low doses. Children who receive vitamin D over a long period of time have an increased risk of stunted growth.
Maternal hypercalcemia (associated with prolonged overdose of vitamin D during pregnancy) can cause increased sensitivity to vitamin D in the fetus, suppression of parathyroid function, specific elf-like appearance syndrome, mental retardation, and aortic stenosis.
In old age, the need for vitamin D may increase due to a decrease in the absorption of vitamin D, a decrease in the skin's ability to synthesize provitamin D3, a decrease in sun exposure, and an increase in the incidence of renal failure.
Overdose
Overdose is manifested by early symptoms caused by hypercalcemia : dry mouth, constipation or diarrhea , thirst, headache , nocturia , pollakiuria , polyuria , lack of appetite, “metallic” taste, vomiting, nausea, severe fatigue, asthenia . Late symptoms of overdose include bone pain, increased blood pressure , changes in urine ( proteinuria , hyaline casts , leukocyturia ), skin itching, conjunctival hyperemia, drowsiness , arrhythmia muscle pain, pancreatitis , stomach pain, weight loss, mood changes.
The drug is immediately discontinued. It is recommended to take large quantities of liquids, eliminate calcium from food, and Vaseline oil. Long-term hypercalcemia leads to deterioration of renal function. Subsequently, calcification (kidneys, blood vessels, heart, lungs), nephrolithiasis and renal failure . In hypercalcemic crisis, saline with loop diuretics, citrates and corticosteroids are administered intravenously. Hemodialysis is indicated .
Interaction
When taken together with vitamin D and calcium supplements, there is a high risk of developing hypercalcemia . Its development is also possible when taken with rifampicin and thiazide diuretics . Simultaneous administration of thyroxine after its withdrawal also causes the development of hypercalcemia .
Dihydrotachysterol enhances the effects of calcium antagonists and cardiac glycosides, so it is necessary to reduce their dose.
The effect of the drug is weakened by taking phenobarbital , phenytoin , carbamazepine , primidone , petroleum jelly, cholestyramine and colestipol .
special instructions
Calcium levels should be monitored in elderly patients with sudden changes in diet and physical activity.
Hypercalcemia or hypercalciuria can be corrected by discontinuing the drug and reducing calcium intake until serum calcium concentrations normalize. Typically this period is 1 week. Therapy can then be continued, starting with half the last dose used.
The effects of dihydrotachysterol may continue for 1-2 months after discontinuation of use.
No data have been identified on the negative effects of dihydrotachysterol when driving vehicles and working with moving mechanisms.
Dihydrotachysterol analogues
Level 4 ATX code matches:
Etalfa
Oksidevit
Tevabon
Alpha D3-Teva
Ergocalciferol
Aquadetrim
Vigantol
Drug A.T.10 , Alpha D3-Teva , Alfadol-Sa , Vigantol , Oksidevit , Etalfa .
Reviews of Dihydrotachysterol
In patients with hypoparathyroidism , calcium absorption in the intestine is reduced and monotherapy with calcium preparations does not maintain its level in the blood, therefore vitamin D in the form of dihydrotachysterol , cholecalciferol , ergocalciferol , which promotes the absorption and absorption of calcium. This drug increases the permeability of the intestinal mucosa to calcium and increases the excretion of phosphates by the kidneys. For patients with hypoparathyroidism, this remedy must be taken constantly, as evidenced by reviews. Everyone notes the effectiveness of the drug and its strict use as prescribed by the doctor after checking the level of calcium in the blood.
- “... I had my thyroid gland removed, I take this drug constantly in a maintenance dose. I constantly do tests. If I stop taking it, I get numbness in my face and cramps.”
- “... I drink constantly after the removal of the gland. When I took A.T.10 everything was fine, but when I switched to this drug, after 10 hours the seizures began.”
- “... This medicine is a very good thing and I need it. After surgery to remove the thyroid gland, I had muscle pain, my arms were stiff, and my mouth muscles were so tight that even my speech was slow. Cramps and all troubles ended when taking this remedy. Now drink constantly under the control of calcium in the blood.”
- “...No thyroid gland - low calcium, calcium D3 and Dihydrotachysterol were prescribed according to the regimen. It helps me prevent stiffness and cramps.”
pharmachologic effect
A synthetic analogue of vitamin D. Increases the concentration of calcium in the blood both by increasing its absorption in the intestines and by mobilizing calcium from the bone. In addition, it stimulates the absorption of phosphate from the small intestine, and also increases the excretion of inorganic phosphorus by the kidneys. Regulates bone mineralization. The effect of the drug appears faster than that of vitamin D2 (ergocalciferol) and vitamin D3 (colecalciferol).
Unlike vitamins D2 and D3, dihydrotachysterol can be used for severe kidney damage, in particular for renal osteodystrophy, since it does not require activation in the kidneys.
