Calcifediol: a review of its pharmacological characteristics and clinical use in correcting vitamin D deficiency

In addition to the role of vitamin D in bone mineralization, calcium and phosphate homeostasis, and skeletal health, evidence suggests an association between vitamin D deficiency and a wide range of chronic conditions. This is of clinical concern given the substantial global prevalence of vitamin D deficiency. Vitamin D deficiency has traditionally been treated with vitamin D3 (cholecalciferol) or vitamin D2 (ergocalciferol). Calcifediol (25-hydroxyvitamin D3) has recently become available more widely.By means of targeted literature searches of PubMed, this narrative review overviews the physiological functions and metabolic pathways of vitamin D, examines the differences between calcifediol and vitamin D3, and highlights clinical trials conducted with calcifediol in patients with bone disease or other conditions.For supplemental use in the healthy population, calcifediol can be used at doses of up to 10 µg per day for children ≥ 11 years and adults and up to 5 µg/day in children 3-10 years. For therapeutic use of calcifediol under medical supervision, the dose, frequency and duration of treatment is determined according to serum 25(OH)D concentrations, condition, type of patient and comorbidities. Calcifediol differs pharmacokinetically from vitamin D3 in several ways. It is independent of hepatic 25-hydroxylation and thus is one step closer in the metabolic pathway to active vitamin D. At comparable doses to vitamin D3, calcifediol achieves target serum 25(OH)D concentrations more rapidly and in contrast to vitamin D3, it has a predictable and linear dose-response curve irrespective of baseline serum 25(OH)D concentrations. The intestinal absorption of calcifediol is relatively preserved in patients with fat malabsorption and it is more hydrophilic than vitamin D3 and thus is less prone to sequestration in adipose tissue.Calcifediol is suitable for use in all patients with vitamin D deficiency and may be preferable to vitamin D3 for patients with obesity, liver disease, malabsorption and those who require a rapid increase in 25(OH)D concentrations.