Vitamin D2

Everyone should know the importance of vitamins to our health. In daily life, people increase their vitamin intake by using some vitamin-rich foods or fruits. However, due to different individual constitutions, some people suffer from vitamin deficiency, which in turn leads to a series of health problems. They need additional vitamin supplements, but they cannot be used indiscriminately.

Everyone knows the importance of vitamin D2, but no one knows how to use it correctly. In response to this situation, we ask professionals to introduce in detail how to use vitamin D2 and what issues should be paid attention to during use.

【Drug name】

Common name: Vitamin D2 Trade name: English name: Vitamin D2 Tablets Chinese pinyin: Weishengsu D2 Pian

The main ingredient of this product is vitamin D2.

Its chemical name is: 9,10-secoergoster-5,7,10(19),22-tetraen-3β-ol.

Molecular formula: C28H44O Molecular weight: 396.66

[Properties] This product is a sugar-coated tablet, which is white after removing the coating.

【Pharmacology and Toxicology】

This product is a vitamin medicine. Vitamin D2 promotes the absorption of calcium by the brush border of the small intestinal mucosa and the reabsorption of phosphorus by the renal tubules, increases blood calcium and phosphorus concentrations, synergizes with parathyroid hormone (PTH) and calcitonin (CT) to promote the release of calcium phosphate from old bones, and maintains and regulates normal plasma calcium and phosphorus concentrations. Vitamin D2 promotes calcium deposition at the site of new bone formation, deposits citrate in the bone, promotes bone calcification and osteoblast function and bone-like tissue maturation. After vitamin D2 is ingested, it is catalyzed by the 25-hydroxylase system in the cell microsomes to produce calcifediol (25-OHD3), which is then catalyzed by the 1-hydroxylase system in the proximal tubular cells of the kidneys to produce biologically active calcitriol [1-25-(OH)2D3]. In animal experiments, after the parathyroid glands of mice were removed, the activity of 1-hydroxylase was lost and calcitriol could not be synthesized. In hypercalcemia, CT secretion increases and 1-hydroxylase activity is inhibited, which reduces the conversion of calcidiol to calcitriol. This confirms that calcitriol metabolism is regulated by PTH and CT, and that phosphate and calcium can also regulate the activity of 1-hydroxylase.

【Pharmacokinetics】

It is absorbed by the small intestine, and its absorption requires bile salts to be bound to special α-globulins and then transported to other parts of the body and stored in the liver and fat. Metabolism and activation first pass through the liver, and then the kidneys. The onset of action is 12 to 24 hours, and the therapeutic effect takes 10 to 14 days. The half-life (t1/2) is 19 to 48 hours, and it can be stored for a long time in adipose tissue. The duration of action is up to 6 months, and repeated administration has a cumulative effect.

【Indications】

1. Used for the prevention and treatment of vitamin D deficiency. Such as: absolute vegetarians, patients with parenteral nutrition, pancreatic insufficiency with malabsorption syndrome, hepatobiliary diseases (liver damage, cirrhosis, obstructive jaundice), small intestinal diseases (fatty diarrhea, localized enteritis, long-term diarrhea), gastrectomy, etc. 2. Used for the treatment of chronic hypocalcemia, hypophosphatemia, rickets, osteomalacia associated with chronic renal insufficiency, familial hypophosphatemia and hypoparathyroidism (postoperative, idiopathic or pseudohypoparathyroidism). 3. Used to treat acute, chronic and potential postoperative tetany and idiopathic tetany.

【Usage and Dosage】

1. Vitamin D-dependent rickets: Adults take 0.25-1.5 mg (10,000-60,000 units) orally per day. The maximum dose is 12.5 mg (500,000 units) per day. For children, the daily dose is 0.075-0.25 mg (3000-10,000 units). The maximum daily dose is 1.25 mg (50,000 units).

2. Familial hypophosphatemia: Adults take 1.25-2.5 mg (50,000-100,000 units) orally per day. 3. Hypoparathyroidism: Adults take 1.25-3.75 mg (50,000-150,000 units) orally per day. Children:

1.25～5mg (50,000～200,000 units).

4. Renal insufficiency: Adults take 1-2.5 mg (40,000-100,000 units) orally per day.

5. Renal bone atrophy: The starting dose for adults is 0.5 mg (20,000 units) per day, and the maintenance dose is 0.25-0.75 mg (10,000-30,000 units) per day; for children, it is 0.1-1 mg (4,000-40,000 units) per day.

【Adverse Reactions】

1. Constipation, diarrhea, persistent headache, loss of appetite, metallic taste in the mouth, nausea and vomiting, thirst, fatigue, and weakness; 2. Bone pain, turbid urine, convulsions, hypertension, increased eye sensitivity to light stimulation, arrhythmia, occasional mental abnormalities, itchy skin, myalgia, severe abdominal pain (sometimes misdiagnosed as pancreatitis), polyuria at night, and weight loss.

[Contraindications] It is contraindicated for patients with hypercalcemia, hypervitaminosis D, hyperphosphatemia and renal rickets.

【Notes】

1. Before treating hypocalcemia, the serum phosphorus concentration should be controlled first, and relevant indicators such as blood calcium should be checked regularly; unless prescribed by a doctor, avoid the simultaneous use of calcium, phosphorus and vitamin D preparations. Aluminum carbonate or aluminum hydroxide gel can be used to control blood phosphorus concentration during hemodialysis. The absorption of phosphorus increases during vitamin D2 treatment, and the dosage of aluminum preparations can be increased as appropriate. 2. Due to individual differences, the dosage of vitamin D2 should be adjusted based on clinical responses. 3. Interference with diagnosis: Vitamin D2 can reduce the concentration of serum phosphatase, and the concentrations of serum calcium, cholesterol, phosphate and magnesium may increase, and the concentrations of calcium and phosphate in urine will also increase. 4. It should be used with caution in the following situations: arteriosclerosis, heart failure, hypercholesterolemia, hyperphosphatemia; high sensitivity to vitamin D and renal insufficiency; when vitamin D2 is used to treat non-renal diseases, if the patient is abnormally sensitive to vitamin D2, renal toxicity may also occur. 5. During the treatment, the following examinations should be performed: serum urea nitrogen, creatinine and creatinine clearance, serum alkaline phosphatase, blood phosphorus, 24-hour urine calcium, ratio of urine calcium to creatinine, blood calcium (regular monitoring should be performed when using therapeutic doses of vitamin D2 to maintain a blood calcium concentration of 2.00-2.50 mmol/L), and bone X-ray examination, etc.

[Use in pregnant and lactating women] Pregnant women with hypercalcemia may be sensitive to vitamin D2 and should pay attention to dosage adjustments.

[Use in Children] Infants have large individual differences in sensitivity to vitamin D2, so the dosage should be determined carefully. The product of serum calcium and phosphorus concentrations [Ca] × [P] (mg/dl) should not be greater than 58.

[Use in elderly patients] Not yet clear.

【Drug Interactions】

1. The magnesium in antacids used together with vitamin D can cause hypermagnesemia, especially in patients with chronic renal failure. 2. Barbiturates, phenytoin sodium, anticonvulsants, primidone, etc. can reduce the effect of vitamin D2. When taking anticonvulsants for a long time, vitamin D should be supplemented to prevent osteomalacia. 3. The combined use of calcitonin and vitamin D can offset the therapeutic effect of the former on hypercalcemia. 4. There is a risk of hypercalcemia when large doses of calcium or diuretics are used together with normal doses of vitamin D. 5. Cholestyramine, colestipol, mineral oil, sucralfate, etc. can reduce the absorption of vitamin D by the small intestine. 6. Be cautious when using digitalis and vitamin D2 together, because vitamin D2 causes hypercalcemia and can easily induce arrhythmias. 7. Using large amounts of phosphorus-containing drugs together with vitamin D can induce hyperphosphatemia.

【Overdose】

1. Taking large doses of vitamin D2 in a short period of time or taking excessive doses of vitamin D2 for a long time can lead to serious poisoning reactions. 2. Hypercalcemia caused by vitamin D2 poisoning can cause systemic vascular calcification, renal calcium precipitation and other soft tissue calcification, leading to hypertension and renal failure. The above adverse reactions often occur when hypercalcemia is accompanied by hyperphosphatemia. Children may experience growth stagnation, which is often seen after long-term use of 1800 units of vitamin D2 per day. The toxic dose may vary due to individual differences. Even if 10,000 units are used daily for more than several months, it can cause toxic reactions in normal people. Vitamin D2 poisoning can cause death due to renal and cardiovascular failure. 3. In addition to discontinuing the use of vitamin D2, the patient should be given a low-calcium diet, drink plenty of water, keep the urine acidic, and carry out symptomatic and supportive treatment. For example, in the event of hypercalcemia crisis, intravenous sodium chloride injection is required to increase urinary calcium excretion. If necessary, diuretics, corticosteroids or calcitonin, or even hemodialysis, should be used. Sun exposure should be avoided until the blood calcium concentration returns to normal before changing the treatment plan.

After the above introduction, everyone should know how to use vitamin D2, but I hope everyone will not use vitamins blindly without authorization. Be sure to read the vitamin instructions in detail. At the same time, decide whether to use it according to the guidance of a professional doctor. I hope everyone can stay healthy.