Vitamin D, Alfacalcidol, Calcitriol, what are the differences, how to choose?

Can I take Vitamin D3 while taking Calcitriol? There is also a drug called Alfacalcidol. Does it have the same effect? ​​Which one is the most suitable?

These three drugs can supplement vitamin D and are the "three musketeers" commonly used in clinical D supplementation. They have the same effect and can promote calcium absorption. The main difference is that the activity is different and the requirements for liver and kidney function are also different. You should choose according to your own health conditions.

◆ Activation process of vitamin D

There are two sources of vitamin D in the human body. One is that the skin synthesizes vitamin D3 under sunlight; the other is the intake of vitamin D2 (mainly in plant foods) and vitamin D3 (mainly in animal foods) through food.

Vitamin D2 and vitamin D3 have the same effect and are collectively called vitamin D, but they still need two steps of activation process to play a physiological role. The first step of activation is mainly completed in the liver, and the second step of activation is mainly completed in the kidneys, and it will eventually be converted into active vitamin D.

There are active vitamin D receptors on the intestinal mucosal cells of the human body, which can greatly promote the absorption rate of calcium ions; active vitamin D can also act on cells on bones to promote differentiation and increase activity; it is also used in the treatment of hypoparathyroidism.

◆ The "Three Musketeers" of vitamin D supplementation

• Vitamin D: Vitamin D2 and D3 have the same effect, but the human body absorbs vitamin D3 better, so the commonly used drug form is vitamin D3, which needs to be activated by the liver and kidneys before it can work.
• Alfacalcidol: It has no direct activity after absorption and needs to be activated by the liver and converted into active vitamin D to work, but it does not need to be activated by the kidneys. It is mainly used for patients with renal insufficiency, but not for those with poor liver function.
• Calcitriol: It is the main active form of vitamin D. After absorption, it does not need to be converted by the liver and kidneys. It can directly act on related receptors and target organs to work. It is mainly used for people with liver and kidney insufficiency.

◆ Choose medication according to health conditions

For those who need to supplement vitamin D, if the liver and kidney function is normal, you can choose vitamin D, which is cheap and has the best cost-effectiveness; if the kidney function is not good, but the liver function is normal, you can choose Alfacalcidol; if the liver and kidney function are not good, or if you are an elderly person, you can choose Calcitriol.

Vitamin D, Alfacalcidol, and Calcitriol are similar drugs. It is generally not recommended to use them together. If you need to use them together, you must pay attention to the total amount not exceeding the standard. If you take too much, it may cause drug accumulation and cause adverse reactions such as hypercalcemia and hypercalciuria. Especially when taking Calcitriol, because it is an active form, it acts quickly and strongly, and adverse reactions are more likely to occur.

Alfacalcidol and vitamin D will act slower than Calcitriol, but accumulation may still occur. This type of drug has individual differences. When taking it, it is recommended to monitor the calcium and phosphorus levels in the blood and adjust the dosage according to the results. If it exceeds the standard, stop the drug and seek medical treatment in time.

To sum up, vitamin D, Alfacalcidol, and Calcitriol can all be used for various diseases caused by vitamin D deficiency.

However, the activation processes of the three are different:

• Vitamin D requires two steps of activation in the liver and kidneys;
• Alfacalcidol requires one step of activation in the liver;
• Calcitriol can work without activation.

The drug must be used under the guidance of a doctor. If you have any questions about the use of the drug, please consult a doctor or pharmacist.