Treatment algorithm

Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups: see disclaimer

ACUTE

insufficiency

1st line – vitamin D

Back
ACUTE
|
insufficiency
1st line – 

vitamin D

The optimal serum concentration of 25-hydroxyvitamin D remains debated.[1]​ A child or adult may be considered vitamin D-insufficient if serum 25-hydroxyvitamin D level is between 52 and 72 nanomoles/L (21-29 nanograms/mL) or if history suggests lack of adequate daily vitamin D (400 IU/day for children aged <1 year; 600 IU/day for those aged ≥1 year; and 600-800 IU/day for adults depending on age, but possibly up to 1500-2000 IU/day) from supplements, diet, and/or adequate sun exposure.[79][85][86]​​​

These patients may be treated with vitamin D replacement following shared decision-making. Vitamin D2 (ergocalciferol) and D3 (colecalciferol) are equally effective in maintaining circulating concentrations of 25-hydroxyvitamin D.[136][137]​​​

For older adults, daily low-dose regimens are often preferred over infrequent large bolus doses. Daily low-dose regimens help reduce the risk of falls in older individuals, whereas infrequent large bolus doses may increase this risk.[67]

Data on the optimal dose for vitamin D insufficiency in pregnancy is lacking.[115]​ If deficiency of vitamin D is identified during pregnancy, supplementation with 1000-2000 IU/day of vitamin D is generally considered to be safe, according to the American College of Obstetricians and Gynecologists (ACOG).[115] Doses above 2000 IU/day of vitamin D are sometimes required, and may be recommended by the patient’s obstetrician, but are typically only used under specialist medical supervision, with appropriate monitoring for potential risks such as hypercalcaemia and toxicity.[128] Seek specialist advice before starting treatment if a woman is pregnant.

Treatment course is typically 6-8 weeks, followed by a lower maintenance dose continued throughout childhood and adulthood.

Primary options

ergocalciferol: children: 2000 IU orally once daily or 50,000 IU orally once weekly for 6-8 weeks, followed by 400-1000 IU/day (children <1 year of age) or 600-1000 IU/day (children ≥1 year of age) as maintenance; non-pregnant adults: 6000 IU orally once daily or 50,000 IU orally once weekly for 8 weeks, followed by 1500-2000 IU/day as maintenance; pregnant adults: 1000-2000 IU orally once daily

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OR

colecalciferol: children: 2000 IU orally once daily or 50,000 IU orally once weekly for 6-8 weeks, followed by 400-1000 IU/day (children <1 year of age) or 600-1000 IU/day (children ≥1 year of age) as maintenance; non-pregnant adults: 6000 IU orally once daily or 50,000 IU orally once weekly for 8 weeks, followed by 1500-2000 IU/day as maintenance; pregnant adults: 1000-2000 IU orally once daily

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Consider – calcium

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ACUTE
|
insufficiency
Consider – 

calcium

Additional treatment recommended for SOME patients in selected patient group

Because inadequate calcium intake may contribute to vitamin D deficiency or insufficiency and many patients do not meet daily calcium requirements from dietary sources alone, all patients at risk of calcium deficiency should be given calcium supplementation.[88][130]

​​There is consensus that vitamin D given in conjunction with calcium reduces fracture risk in the older population, and is recommended in this group.[67] 

Calcium supplementation should continue indefinitely or until adequate intake is achieved through dietary sources.

While some studies suggest no significant cardiovascular risk associated with calcium supplements, other research indicates potential concerns, particularly at higher doses.[131][132][133][134]

Primary options

calcium carbonate: children: 45-65 mg/kg/day orally given in 4 divided doses; adolescents/adults: 1-2 g/day orally given in 3-4 divided doses

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deficiency

1st line – vitamin D

Back
ACUTE
|
deficiency
|
disorders of vitamin D intake or absorption
1st line – 

vitamin D

The optimal serum concentration of 25-hydroxyvitamin D remains debated.[1] Some experts recommend a goal serum 25-hydroxyvitamin D concentration >75 nanomoles/L (>30 nanograms/mL), particularly in older adults, in order to maximise vitamin D effects on the skeleton and on calcium and phosphate metabolism.​[117][118][83][84][3][119]​​​​

Vitamin D2 (ergocalciferol) and D3 (colecalciferol) are equally effective in maintaining circulating concentrations of 25-hydroxyvitamin D.[136][137]​​​

Some patients, for example those with intestinal or fat malabsorption syndromes (including liver failure), or who have a history of gastric bypass surgery, often require higher doses of vitamin D under specialist supervision. Patients taking anticonvulsants, glucocorticoids, or other drugs that activate the steroid and xenobiotic receptors (e.g., antiretroviral therapy [ART], rifampicin, St. John's wort) may also require higher doses of vitamin D.

The threshold at which vitamin D becomes toxic is not well defined. The National Academy of Medicine sets the tolerable upper intake level (UL) for vitamin D at 4000 IU/day for healthy adults and children aged 9-18 years.[79] The UL is lower for infants and children up to 9 years, varying by age. In some cases, patients may need doses exceeding the National Academy of Medicine's UL to correct deficiency, requiring specialist (endocrinology) oversight and close monitoring to avoid toxicity (e.g., people with malabsorption syndromes).

For older adults, daily low-dose regimens are often preferred over infrequent large bolus doses. Daily low-dose regimens help reduce the risk of falls in older individuals, whereas infrequent large bolus doses may increase this risk.[67]

Data on the optimal dose for vitamin D deficiency in pregnancy is lacking.[115]​ If deficiency of vitamin D is identified during pregnancy, supplementation with 1000-2000 IU/day of vitamin D is generally considered to be safe, according to the American College of Obstetricians and Gynecologists (ACOG).[115] Doses above 2000 IU/day of vitamin D are sometimes required, and may be recommended by the patient’s obstetrician, but are typically only used under specialist medical supervision, with appropriate monitoring for potential risks such as hypercalcaemia and toxicity.[128] Seek specialist advice before starting treatment if a woman is pregnant.

Dosing regimens have been recommended.[3]​​ Treatment course is typically 6-8 weeks, followed by a lower maintenance dose continued throughout childhood and adulthood.​

Primary options

ergocalciferol: children: 2000 IU orally once daily or 50,000 IU orally once weekly for 6-8 weeks, followed by 400-1000 IU/day (children <1 year of age) or 600-1000 IU/day (children ≥1 year of age) as maintenance; non-pregnant adults: 6000 IU orally once daily or 50,000 IU orally once weekly for 8 weeks, followed by 1500-2000 IU/day as maintenance; pregnant adults: 1000-2000 IU orally once daily

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OR

colecalciferol: children: 2000 IU orally once daily or 50,000 IU orally once weekly for 6-8 weeks, followed by 400-1000 IU/day (children <1 year of age) or 600-1000 IU/day (children ≥1 year of age) as maintenance; non-pregnant adults: 6000 IU orally once daily or 50,000 IU orally once weekly for 8 weeks, followed by 1500-2000 IU/day as maintenance; pregnant adults: 1000-2000 IU orally once daily

More

Consider – calcium

Back
ACUTE
|
deficiency
|
disorders of vitamin D intake or absorption
Consider – 

calcium

Additional treatment recommended for SOME patients in selected patient group

Because inadequate calcium intake may contribute to vitamin D deficiency and many patients do not meet daily calcium requirements from dietary sources alone, all patients at risk of calcium deficiency should be given calcium supplementation.[88]

There is consensus that vitamin D given in conjunction with calcium reduces fracture risk in the older population, and is recommended in this group.[67] 

Calcium supplementation should continue indefinitely or until adequate intake is achieved through dietary sources.

While some studies suggest no significant cardiovascular risk associated with calcium supplements, other research indicates potential concerns, particularly at higher doses.[131][132][133][134]

Primary options

calcium carbonate: children: 45-65 mg/kg/day orally given in 4 divided doses; adolescents/adults: 1-2 g/day orally given in 3-4 divided doses

More

1st line – vitamin D

Back
ACUTE
|
deficiency
|
disorders of vitamin D metabolism
1st line – 

vitamin D

The optimal serum concentration levels of 25-hydroxyvitamin D remains debated.[1] Some experts recommend a goal serum 25-hydroxyvitamin D concentration >75 nanomoles/L (>30 nanograms/mL), particularly in older adults, in order to maximise vitamin D effects on the skeleton and on calcium and phosphate metabolism.​[117][118][83][84][3][119]​​​​

Vitamin D2 (ergocalciferol) and D3 (colecalciferol) are equally effective in maintaining circulating concentrations of 25-hydroxyvitamin D.[136]

For older adults, daily low-dose regimens are often preferred over infrequent large bolus doses. Daily low-dose regimens help reduce the risk of falls in older individuals, whereas infrequent large bolus doses may increase this risk.[67]

Data on the optimal dose for vitamin D deficiency in pregnancy is lacking.[115]​ If deficiency of vitamin D is identified during pregnancy, supplementation with 1000-2000 IU/day of vitamin D is generally considered to be safe, according to the American College of Obstetricians and Gynecologists (ACOG).[115] Doses above 2000 IU/day of vitamin D are sometimes required, and may be recommended by the patient’s obstetrician, but are typically only used under specialist medical supervision, with appropriate monitoring for potential risks such as hypercalcaemia and toxicity.[128] Seek specialist advice before starting treatment if a woman is pregnant.

Treatment course is typically 6-8 weeks, followed by a lower maintenance dose continued throughout childhood and adulthood.​

Primary options

ergocalciferol: children: 2000 IU orally once daily or 50,000 IU orally once weekly for 6-8 weeks, followed by 400-1000 IU/day (children <1 year of age) or 600-1000 IU/day (children ≥1 year of age) as maintenance; non-pregnant adults: 6000 IU orally once daily or 50,000 IU orally once weekly for 8 weeks, followed by 1500-2000 IU/day as maintenance; pregnant adults: 1000-2000 IU orally once daily

More

OR

colecalciferol: children: 2000 IU orally once daily or 50,000 IU orally once weekly for 6-8 weeks, followed by 400-1000 IU/day (children <1 year of age) or 600-1000 IU/day (children ≥1 year of age) as maintenance; non-pregnant adults: 6000 IU orally once daily or 50,000 IU orally once weekly for 8 weeks, followed by 1500-2000 IU/day as maintenance; pregnant adults: 1000-2000 IU orally once daily

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Plus – 1,25-dihydroxyvitamin D3 or active analogue

Back
ACUTE
|
deficiency
|
disorders of vitamin D metabolism
Plus – 

1,25-dihydroxyvitamin D3 or active analogue

Treatment recommended for ALL patients in selected patient group

Given that acquired or inherited conditions of vitamin D metabolism adversely affect the metabolism of 25-hydroxyvitamin D to 1,25-dihydroxyvitamin D, or the recognition of 1,25-dihydroxyvitamin D, vitamin D replacement alone is not usually sufficient but should be given together with 1,25-dihydroxyvitamin D3 (calcitriol) or one of its active analogues (e.g., paricalcitol, doxercalciferol).

Patients with chronic kidney disease who have a GFR of <50% of normal usually require 1,25-dihydroxyvitamin D3 or one of its active analogues in conjunction with vitamin D to treat and prevent secondary hyperparathyroidism. This is due to a decreased capacity to produce 1,25-dihydroxyvitamin D, which causes secondary hyperparathyroidism.

Primary options

calcitriol: children and adults: consult specialist for guidance on dose

OR

paricalcitol: children and adults: consult specialist for guidance on dose

OR

doxercalciferol: children and adults: consult specialist for guidance on dose

Consider – calcium

Back
ACUTE
|
deficiency
|
disorders of vitamin D metabolism
Consider – 

calcium

Additional treatment recommended for SOME patients in selected patient group

Because inadequate calcium intake may contribute to vitamin D deficiency and many patients do not meet daily calcium requirements from dietary sources alone, all patients at risk of calcium deficiency should be given calcium supplementation.[88]

There is consensus that vitamin D given in conjunction with calcium reduces fracture risk in the older population, and is recommended in this group.[67]

Furthermore, patients with chronic kidney disease have high-normal or elevated serum phosphate levels and a decreased capacity to produce 1,25-dihydroxyvitamin D, which causes secondary hyperparathyroidism. Therefore, they need to maintain a serum 25-hydroxyvitamin D of between 75-250 nanomoles/L (30-100 nanograms/mL), which can independently reduce parathyroid hormone levels, and control their serum phosphorus level by using a phosphate binder such as calcium carbonate.[14][138]

Calcium supplementation should continue indefinitely or until adequate intake is achieved through dietary sources.

While some studies suggest no significant cardiovascular risk associated with calcium supplements, other research indicates potential concerns, particularly at higher doses.[131][132][133][134]

Primary options

calcium carbonate: children: 45-65 mg/kg/day orally given in 4 divided doses; adolescents/adults: 1-2 g/day orally given in 3-4 divided doses

More

Consider – phosphate

Back
ACUTE
|
deficiency
|
disorders of vitamin D metabolism
Consider – 

phosphate

Additional treatment recommended for SOME patients in selected patient group

Phosphate supplementation is not usually necessary unless there is an acquired or inherited disorder causing phosphate wasting in the kidneys, such as hypophosphataemic rickets or oncogenic osteomalacia.​[8][9] These patients require phosphate supplementation in addition to vitamin D replacement and 1,25-dihydroxyvitamin D3 or one of its active analogues.

Caution should be exercised when giving phosphate supplements because high-dose phosphate multiple times a day causes a reduction in ionised calcium, resulting in an increase in parathyroid hormone production and tertiary hyperparathyroidism. Therefore, smaller doses of phosphate should be taken more frequently throughout the day to maintain a normal serum phosphate level without causing significant hyperparathyroidism.

Phosphate supplementation should be avoided in patients with chronic kidney disease, due to their already high-normal or elevated serum phosphate levels.

Primary options

sodium phosphate/potassium phosphate: children and adults: consult specialist for guidance on dose

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Please note that formulations/routes and doses may differ between drug names and brands, drug formularies, or locations. Treatment recommendations are specific to patient groups. See disclaimer

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