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ATC Group: A11C Vitamin A and D, incl. combinations of the two

Anatomical Therapeutic Chemical Classification System

Hierarchical Position

Level
Code
Title
1
A
Alimentary tract and metabolism
2
A11
Vitamins
3
A11C
Vitamin A and D, incl. combinations of the two

Contents

Code
Title
A11CA
Vitamin A, plain
A11CB
Vitamin A and D in combination
A11CC
Vitamin D and analogues

Active Ingredients

Chemical substance
Description
Alfacalcidol

Alfacalcidol is Vitamin D-hormone analog (an active metabolite of Vitamin D), which performs important functions in regulation of the calcium balance and the bone metabolism and is activated by the enzyme 25-hydroxylase (converted rapidly in the liver to 1,25-dihydroxyvitamin D) for systemic and in osteoblasts for local D-hormone actions.

beta-Carotene
Calcidiol

Vitamin D3 must undergo a two-step metabolic process to be active; the first step occurs in the microsomal fraction of the liver where Vitamin D is hydroxylated at position 25 (25-hydroxycholecalciferol or calcifediol); the second step takes place in the kidney where 1,25-dihydroxycholecalciferol or calcitriol is formed due to the activity of enzyme 25-hydroxycholecalciferol 1-hydroxylase. Vitamin D increases absorption of calcium and phosphorus in the intestine and improves normal bone formation and mineralization.

Calcitriol

Calcitriol is the most active known form of vitamin D3 in stimulating intestinal calcium transport. In physiological amounts it augments the intestinal absorption of calcium and phosphate and plays a significant part in the regulation of bone mineralisation.

Doxercalciferol

Doxercalciferol is a synthetic vitamin D2 analog that requires metabolic activation to form the active 1α,25-(OH)2D2 metabolite, which binds to the vitamin D receptor (VDR) to result in the selective activation of vitamin D responsive pathways. Vitamin D and doxercalciferol have been shown to reduce PTH levels by inhibiting PTH synthesis and secretion.

Vitamin A

Vitamin A plays an important role in the visual process. It is isomerised to the 11-cis isomer and subsequently bound to the opsin to form the photoreceptor for vision under subdued light. Vitamin A also participates in the formation and maintenance of the integrity of epithelial tissues and mucous membranes.

Vitamin D2

Vitamin D2 (ergocalciferol) is a fat soluble vitamin. In conjunction with parathyroid hormone and calcitonin, it regulates calcium haemostasis. Ergocalciferol metabolites promote active absorption of calcium and phosphorous by the small intestine, increase rate of excretion and resorption of minerals in bone and promote resorption of minerals in bone and promote resorption of phosphate by renal tubules.

Vitamin D3

In its biologically active form vitamin D3 stimulates intestinal calcium absorption, incorporation of calcium into the osteoid, and release of calcium from bone tissue. In the small intestine it promotes rapid and delayed calcium uptake. The passive and active transport of phosphate is also stimulated.

Monographs

Monograph
Type
Country
ONE-ALPHA Capsules
MPI, EU: SmPC
UK
ONE-ALPHA Solution for injection
MPI, EU: SmPC
UK
ROCALTROL Soft capsules
MPI, EU: SmPC
UK