Standard dose :  Vitamin D3: Route: IM, Standard dose: 50,000 iu , Max dose: 50,000 iu; 50,000 iu/wk x 4 weeks then once a month thereafter 

Acceptable routes :  IM ONLY

Pharmacologic category: Vitamin, Fat Soluble

Pregnancy: Safe to use during pregnancy in recommended doses

Indications: Anyone living in UT  (given the way Utah sits on the equator, even sitting outside all day is likely not enough sunlight to maintain optimal levels) without contraindications for treatment.. Certain medications have been found to contribute to deficiency of vitamin D, including some anti-seizure medications, bile acid sequestrants, oral corticosteroids, and weight loss medications, which bind fats. Certain hormones can be affected by Vitamin D levels and testosterone levels can decrease as much as 25% with inadequate vitamin D levels.

Basic Information

Vitamin D is crucial to the building and maintenance of healthy bones and teeth.  Calcium, the primary component of bone, is only properly absorbed by your body when vitamin D is present. Vitamin D is created within the body when direct sunlight converts a chemical in your skin into an active form of the vitamin. There are not many foods that contain vitamin D, but you can find it in fortified milk, fortified cereals, and fatty fish, like salmon, mackerel, and sardines. Unfortunately, most people do not get the necessary amount of vitamin D. Therefore, supplementation is needed. Vitamin D3 is the perfect supplement as it is the natural form of vitamin D that your body makes from sunlight. Vitamin D can come in several forms. The two major forms are vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). The recommended form of vitamin D for supplementation is cholecalciferol. Cholecalciferol is metabolized to its active form, calcitriol, which increases the body’s absorption of calcium and phosphorus. Some evidence suggests calcitriol plays a role in the immune system and may inhibit cancer growth and stimulate cell differentiation. Receiving vitamin D3 injections can treat and prevent the symptoms of vitamin D deficiency, including fatigue and bone pain. Vitamin D deficiency has been associated with an increased risk of death from cardiovascular disease, cognitive impairment in the elderly, severe childhood asthma and cancer.Vitamin D is a fat-soluble vitamin. Very few foods naturally contain vitamin D (fatty fish livers are the exception), so dermal synthesis is the major natural source of the vitamin. Vitamin D from the diet or dermal synthesis is biologically inactive and requires enzymatic conversion to active metabolites. Vitamin D is converted enzymatically in the liver to 25-hydroxyvitamin D (25[OH]D), the major circulating form of vitamin D, and then in the kidney to 1,25-dihydroxyvitamin D, the active form of vitamin D. Vitamin D and its metabolites have a significant clinical role because of their interrelationship with calcium homeostasis and bone metabolism. Rickets (children) and osteomalacia (children and adults) due to severe vitamin D deficiency are now uncommon except in populations with unusually low sun exposure, lack of vitamin D in fortified foods, and malabsorptive syndromes. Subclinical vitamin D deficiency, as measured by low serum 25(OH)D, is very common. In the National Health and Nutrition Examination Survey (NHANES) 2005 to 2006, 41.6 percent of adult participants (≥20 years) had 25(OH)D levels below 20 ng/mL (50 nmol/L). This degree of vitamin D deficiency may contribute to the development of osteoporosis and an increased risk of fractures and falls in older adults. Vitamin D may also regulate many other cellular functions.

Absorption: Dietary vitamin D is incorporated into micelles, absorbed by enterocytes, and then packaged into chylomicrons. Disorders associated with fat malabsorption, such as celiac disease, Crohn disease, pancreatic insufficiency, cystic fibrosis, short gut syndrome, and cholestatic liver disease, are associated with low serum 25-hydroxyvitamin D (25[OH]D) levels.

Deficiency:

Vitamin D deficiency or resistance is caused by one of four mechanisms 

• Impaired availability of vitamin D, secondary to inadequate dietary vitamin D, fat malabsorptive disorders, and/or lack of sunlight (photoisomerization)

• Impaired hydroxylation by the liver to produce 25-hydroxyvitamin D (25[OH]D)

• Impaired hydroxylation by the kidneys to produce 1,25-dihydroxyvitamin D (vitamin D-dependent rickets type 1, chronic renal insufficiency)

• End-organ insensitivity to vitamin D metabolites 

Several studies have shown suboptimal serum levels of 25(OH)D and vitamin D intake in the United States and other countries. Lack of vitamin D activity leads to reduced intestinal absorption of calcium and phosphorus. Early in vitamin D deficiency, hypophosphatemia is more marked than hypocalcemia. With persistent vitamin D deficiency, hypocalcemia occurs and causes secondary hyperparathyroidism, which leads to phosphaturia, demineralization of bones, and, when prolonged and severe, to osteomalacia in adults and rickets and osteomalacia in children.Subclinical vitamin D deficiency occurs even in developed countries and is associated with osteoporosis, increased risk of falls, and possibly fractures.

Glucocorticoids, when used chronically in high doses, inhibit intestinal vitamin D-dependent calcium absorption, which is one of the mechanisms whereby chronic glucocorticoid excess leads to osteoporosis and fractures. 

Vitamin D stores decline with age, especially in the winter. Controlled trials have demonstrated that vitamin D and calcium supplementation can reduce the risk of falls and fractures in older adults.

Benefits:

Endocrine Health/Metabolism:Plays an important role in the synthesis of many vital hormones-deficiency can cause a 25% reduction in testosterone production. Insufficient hormone levels can lead to numerous issues, including weight gain.

Musculoskeletal Health:May help protect older adults from osteoporosis. Adequate levels are needed for bone growth and dental health.Cholecalciferol is metabolized to its active form, calcitriol, which increases the body’s absorption of calcium and phosphorus.

Mood Health:Deficiency can lead to several mood disorders, including anxiety and depression. 

Cardiovascular Health: Vitamin D3-calcitriol helps strengthen cardiomyocyte function, vascular smooth muscle cells, and the vascular endothelium.

Immune health :Boosts Immune activity by up-regulating specific genes that increase cellular production of natural compounds that protect us against pathogens, promotes normal inflammatory balance.  Studies show it may inhibit cancer growth and stimulate cell differentiation.