Vitamin D Deficiency - Advice on the Management of Adults over 18 years with Vitamin D Deficiency or Insufficiency in Primary and Secondary Care

Publication: 23/08/2013  
Next review: 02/10/2023  
Clinical Guideline
ID: 3399 
Approved By: Leeds Area Prescribing Committee 
Copyright© Leeds Teaching Hospitals NHS Trust 2020  


This Clinical Guideline is intended for use by healthcare professionals within Leeds unless otherwise stated.
For healthcare professionals in other trusts, please ensure that you consult relevant local and national guidance.

Advice on the Management of Adults over 18 years with Vitamin D Deficiency or Insufficiency in Primary and Secondary Care

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1. Background

This pathway is intended for use by healthcare professionals who see patients at risk of vitamin D deficiency. It is not a screening pathway and Vitamin D testing is not a screening tool. The aim of this guidance is to give recommendations on when measuring of vitamin D levels may be appropriate and how to proceed when abnormal vitamin D levels are seen.

Vitamin D is essential for good bone health but there is still uncertainty around its role in other diseases such as cancer, heart disease and diabetes1.

The main manifestation of vitamin D deficiency is osteomalacia in adults and rickets in children, which the Scientific Advisory Committee on Nutrition (SACN) suggests are generally associated with increased risk at plasma 25-hydroxyvitamin D (25(OH)D) concentrations below 20-25 nmol/L. Less severe vitamin D deficiency, sometimes termed vitamin D insufficiency, may lead to secondary hyperparathyroidism, bone loss, muscle weakness, falls and fragility fractures in older people 2.

The term vitamin D is used for a range of compounds. Vitamin D2 is known as ergocalciferol. Vitamin D3 is known as colecalciferol. 1microgram colecalciferol / ergocalciferol are equivalent to 40units.

Colecalciferol (vitamin D3) is considered the preferred form of vitamin D for treatment. It has been reported that colecalciferol raises vitamin D levels more effectively than ergocalciferol (vitaminD2) and has a longer duration of action.2

The following guideline is based on the references cited and aligns local practice with recent NOS2 and NICE3 guidance, where possible.

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2. Symptoms of vitamin D deficiency4

  • Bone discomfort or pain (often throbbing) in lower back, pelvis, and lower extremities.
  • Muscle aches/ weakness -usually proximal, difficulty rising from sitting and waddling gait.
  • Chronic widespread pain.

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3. Diagnosis

Vitamin D status is monitored by measuring serum 25-hyroxyvitamin D (25(OH)D) concentration. Based on the performance of the local Vitamin D assay, we recommend the following: 

Serum 25(OH)D conc

Vitamin D status


<25 nmol/l


Musculoskeletal pain + weakness in adults (osteomalacia).

25 – 49 nmol/l


Possibly associated with increased risk of disease

50 – 100 nmol/l



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4. Who to test?

There is currently a lack of evidence to support routine screening of vitamin D levels in general practice1 and NICE recommend that Health professionals should not routinely test people's vitamin D status unless they have symptoms of vitamin D deficiency, they are considered to be at particularly high risk of deficiency (for example, they have very low exposure to sunlight) or there is a clinical reason to do so2.


Testing criteria: Patient should meet (A), (B) or (C)

  • Confirmed or suspected bone disease e.g. low bone mineral density, osteomalacia, osteoporosis, Paget’s disease of bone, hyperparathyroidism osteopenia
  • Other conditions as specified by secondary care specialist guidelines e.g. melanoma, fertility

The patient has one or more of the following symptoms:


  • Unexplained widespread or localised bone pain and tenderness
  • Unexplained muscle weakness and pain.
  • Exclude other causes e.g. inflammatory arthritis, polymyalgia rheumatica or hypothyroidism.


The patient is deemed high risk for deficiency and has one or more RISK FACTORS:

  • Reduced exposure to sunlight e.g. due to being housebound, having skin covered when outside or routine use of high factor sunscreen.
  • Dark skin.
  • Over 65s, (particularly with a history of falls or in care home not already prescribed Ca + Vit D)
  • Pregnant + breastfeeding women, especially teenagers and younger women
  • Obese people i.e. BMI>30.
  • Those who may have fat malabsorption e.g. CF, Crohns or bariatric patients.
  • Those taking medication that may increase vitamin D catabolism e.g. anti-epilepsy drugs, glucocorticoids, systemic anti-fungal drugs such as ketoconazole, cholestryramine, rifampicin, HIV drugs.



  • Particularly IV zoledronic acid or SC denosumab

It is worthwhile encouraging all patients with risk factors – even those not exhibiting symptoms – to make lifestyle changes in order to achieve adequate amounts of vitamin D, but it is not necessary to measure their levels, e.g. patients over 65years in care homes should be encouraged to go or be taken outdoors regularly.

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5. What baseline tests are required?

  • Vitamin D (25OHD)
  • Adjusted Calcium (to exclude hypercalcaemia and provide a baseline for monitoring)
  • U+Es

Note parathyroid hormone (PTH) may be elevated in deficiency states but routine testing is not required.

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6. What monitoring is required?

If loading dose vitamin D correction is used then adjusted calcium levels should be checked at baseline and within 4 weeks 2.

If adjusted calcium is elevated at baseline seek advice from endocrinology before commencing vitamin D supplementation.

In most cases, at recommended doses, routine monitoring of 25(OH) vitamin D after replacement is NOT necessary.

The exceptions to this for repeat testing are:

  • People with ongoing symptoms likely attributable to continued vitamin D deficiency
  • Vitamin D replacement is part of the treatment (usually bone diseases)
  • Unmodifiable major risk factors for continued low 25(OH) vitamin D which may alter normal vitamin D metabolism (e.g. malabsorption, medication).
  • Higher than standard recommended vitamin D3 supplementation
  • Intramuscular vitamin D injections
  • Anti-resorptive therapy (particularly, zoledronic acid and denosumab)
  • Hypercalcaemia
  • Symptoms suggestive of vitamin D toxicity

Steady state levels of 25 (OH) vitamin D may not be reached for up to 6 months.

If repeat testing and monitoring is indicated, check:

  • Adjusted Calcium
  • Vitamin D (25OHD)
  • U+Es

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7. Lifestyle Advice and Prevention

80-90% of the body’s vitamin D requirement is obtained from ultraviolet B sunlight exposure, with only a minimal amount obtainable from food. It follows that adequate exposure to sunlight is essential for good health.

During the summer two or three exposures of 20 minutes (of at least the face and arms without sunscreen and not behind glass) each week should provide adequate amounts of vitamin D for most fair skinned individuals 5. In the UK, from October to April sun exposure is not adequate for synthesis of vitamin D and levels must be maintained by using tissue stores and dietary sources.

NB. Patients with melanoma and fertility issues should seek specialist advice.

Department of Health Recommendations 6,7

All children, aged 4 years and over, and adults, including pregnant and breast feeding women, should consider taking a supplement, particularly during autumn and winter.

10 micrograms (400units) vitamin D per day

High risk groups should consider taking a supplement throughout the year.
High risk groups are:

  • People with little sun exposure e.g. those in institutions such as care homes, or who always cover their skin when outside.
  • People with dark skin

10 micrograms (400units) vitamin D per day

Lifestyle advice should be reinforced with people at risk of deficiency.

Prescribing of nutritional supplements on the NHS to these groups is not recommended.

Routine testing in these groups in theabsence of symptoms is not recommended.

Food sources which can contribute to vitamin D status are:

  1. Oily fish such as herring, sardines, mackerel, salmon, tuna, pilchards, trout, kippers and eel.
  2. Egg yolk, meat, offal, milk and meat contain small amounts but this varies during seasons. Liver is also a rich source of vitamin A and consumption should be limited to once a week to avoid toxicity and avoided in pregnancy.
  3. Vitamin D fortified foods such as margarines and cereals & powdered milk (check product labels).

Suitable supplements are available to buy from pharmacies, health food shops and supermarkets. Patients should consult their community pharmacist if they are unsure which product to buy.

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8. Safety Issues

UK Scientific Advisory Committee on Nutrition (SACN) reviewed the evidence and concluded that an upper limit of 4,000 units (100μg) per day is safe for adults and children over 11 years of age including pregnant and lactating women 8. (NOS84)

Research suggests up to 10,000 units can be taken daily by healthy people for up to 16 weeks without toxicity. Excessive intake can rarely lead to hypercalcaemia; symptoms include muscle weakness, apathy, headache, anorexia, nausea and vomiting.2

High dose, intermittent vitamin D supplementation has been associated with falls and increased fracture risk and should be avoided, unless there is an urgency to replace vitamin D 2, 9.

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9. Interactions 10,11

Vitamin D3 (colecalciferol) can interact with other medications as this may result in serum 25(OH) levels not improving despite adequate loading.

The following is a list of medications which frequently interact with colecalciferol.

It is not exhaustive. The BNF and SPC should be consulted for further information.

Drug or Class


Thiazide and thiazide-like diuretics

Increases risk of hypercalcaemia


Decreases effect of colecalciferol


Decreases absorption of colecalciferol

Triazole antifungals

Decreases exposure to colecalciferol


Colecalciferol increases risk of digoxin toxicity


Decreases absorption of colecalciferol


Decreases effect of colecalciferol


Decreases effects of colecalciferol


Decrease activation of vitamin D

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10. When to seek advice and when to refer to secondary care?

ADVICE - Seek advice from secondary care if:

Use usual ‘advice and guidance’ route.

  • Chronic liver or kidney disease (CKD 4 or above)
  • Primary hyperparathyroidism
  • History of renal stones
  • Hypercalcaemia / metastatic calcification
  • Patient with chronic granuloma forming disorders (sarcoidosis or TB), chronic fungal infections or lymphoma.

Please note standard high dose vitamin D replacement doses in these patients may cause harm, particularly hypercalcaemia.


If testing in appropriate patients (see section 4), consider referral to Endocrinology if:

  1. Patients with known METABOLIC BONE PROBLEMS, including osteoporosis, are unable to achieve 25 (OH) vitamin D levels of 50 nmol/L or greater despite appropriate loading and maintenance therapy for more than 6 months.
  2. Patients with RISK FACTORS (as below) and are unable to achieve 25(OH) vitamin D levels of 50 nmol/L or greater despite appropriate loading and maintenance therapy for more than 6 months.
    1. Malabsorption (short-bowel syndrome, pancreatic issues, gastric bypass surgery, coeliac disease etc)
    2. OR medication interference (see section 9)
    3. OR elevated BMI >40kg/m2
  3. Patients who are UNABLE TO TOLERATE oral vitamin D3 (colecalciferol) preparations.
  4. Patients with symptoms of OSTEOMALACIA and are unable to achieve 25(OH) vitamin D levels of 50 nmol/L or greater despite appropriate loading and maintenance therapy for more than 6 months.

If the patient does not meet criteria for referral but continues to be symptomatic with insufficient vitamin D levels despite 6 months of maintenance treatment, then evaluate adherence issues, consider a loading dose or consider increase in maintenance dose within parameters described below (section 11).

Please note it would be unusual for a patient to be symptomatic from vitamin D deficiency with 25 (OH) vitamin D levels greater than 50 nmol/L.

Advice can be sought from Endocrinology for patients who do not meet the referral criteria, where it is appropriate to be rechecking vitamin D levels.

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11. Treatment Regimes for NON-PREGNANT Adults


Should follow correction of deficiency or insufficiency combined with food and lifestyle advice.

NHSE recommends maintenance therapy for vitamin D deficiency should NOT routinely be prescribed in primary care 12.

  • Colecalciferol tablets 800-2000 unit tablets ONCE daily individualised to patient circumstances.
    • Start at lower doses within this range.
    • Higher doses (within this range) may be required in Winter months compared to Summer months.
    • 25(OH) vitamin D levels may take up to 6 months to reach steady state and rapidly fall once supplementation is ceased. Therefore maintenance therapy may need to be long-term.
    • If the patient continues to be genuinely symptomatic despite 6 months of maintenance treatment, then evaluate adherence issues.
    • If no adherence issues after 6 months of treatment, then check Vitamin D levels and if still insufficient consider increase in maintenance dose within parameters described or loading dose followed by maintenance if appropriate.
  • Advise to purchase a supplement suitable to supply 20 – 50micrograms (800 to 2000 units) daily.
  • Available in supermarkets and pharmacies: ask community pharmacist for latest advice. 


  • Calcium + vitamin D (calcium as maximum calcium carbonate 2.5g [equivalent to 1.5g calcium]) and 1000 units daily vitamin D3 when given as combined preparation) for frail, institutionalised people to prevent falls and for those with osteoporosis/osteopenia if daily recommended intake of calcium not met.

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12. Treatment Regimes in Pregnancy 13, 14

Vitamin D use in human pregnancy is not associated with an increased risk of congenital malformation, although the data are insufficient to confirm that there is unequivocally no risk. In the general population, an upper physiological limit of 10,000units of vitamin D/day has been suggested. Above this daily dose, adverse effects are theoretically more likely so bolus injections or oral doses of more than 10,000units per day should be avoided and very high single bolus doses (i.e. 300,000 - 500,000units) should NOT be used in pregnancy.

Safety data relate to use in the second or third trimesters and given lack of data use of high dose vitamin D in the first trimester is therefore usually avoided.

Supplementation is recommended for ALL pregnant women in accordance with department of health guidance. They should be signed posted to the healthy start programme for further information if eligible.

Supplements are available free of charge to qualifying pregnant or breastfeeding women and children via the Healthy Start scheme – see website for eligibility criteria,

Healthy Start Vitamins are not available on prescription.

Testing: Criteria for vitamin D testing in pregnant women should follow the standard adult guidance (section 4).

Preparations: A number of licensed oral vitamin D products are available in a variety of strengths and formulations such as tablets, capsules, drops and solutions. Examples of licensed products which enable recommended dosing regimens of 1000units to 4000units/day and do not strictly contraindicate use in pregnancy include: Aviticol D3 1000unit capsules, Invita D3 800unit capsules, Fultium D3® 3200unit capsules or 2740unit/mL drops, Desunin® 4000unit tablets and Stexerol-1000unit D3® tablets 14.

Lifestyle advice during pregnancy and breastfeeding:


For all pregnant women: Vitamin D3 (colecalciferol) tablets 400 units once a day

For at risk pregnant women: Vitamin D3 (colecalciferol) tablets 1000 units a day

Higher Risk pregnant women include;

  • Increased skin pigmentation,
  • Reduced exposure to sunlight,
  • Socially excluded
  • Obese BMI ≥ 30kg/m2

For pregnant women at risk of pre-eclampsia a Calcium + vitamin D combination is recommended.

The optimal dose to correct vitamin D deficiency safely in pregnancy is not still clear from the available data. We base the following advice on UKMi information (January 2019)14 and RCOG guidance13.

Treatment of INSUFFICIENCY in PREGNANCY: 25(OH) vitamin D 25-49 nmol/L

Only use this regime in SECOND or THIRD trimester

Vitamin D3 (colecalciferol) capsules: 2000 units DAILY for 10 weeks


Vitamin D3 (colecalciferol) capsules: 20,000 units ONCE WEEKLY for 8 weeks**

  • Monitor adjusted calcium at baseline and 4 weeks after commencing treatment.
  • Follow loading dose with MAINTENANCE vitamin D3 (800-2000 units daily)
  • Repeat testing of 25(OH) vitamin D levels is NOT usually necessary unless patient remains symptomatic, or has other risk factors for remaining vitamin D deficient (see sections 4 and 6)

**Note this is unlicensed in pregnancy



Only use this regime in SECOND or THIRD trimester

Can use RAPID CORRECTION regime in the following scenarios:

  • 25(OH) vitamin D levels <25 nmol/L
  • Third trimester of pregnancy and rapid correction required

Vitamin D3 (colecalciferol) capsules: 4000 units DAILY for 8 weeks

(If more rapid correction than this is required seek advice from Endocrinology)


Vitamin D3 (colecalciferol) capsules: 20,000 units ONCE WEEKLY for 14 weeks**

If liquid required prescribe:

Colecalciferol 25,000units/1ml oral solution unit dose ampoules sugar free, 1 ampoule once a week for 6 weeks 

  • Monitor adjusted calcium 4 weeks at baseline and after commencing treatment.
  • Follow loading dose with MAINTENANCE vitamin D3 (800-2000 units daily)
  • Repeat testing of 25(OH) vitamin D levels is NOT usually necessary unless patient remains symptomatic, or has other risk factors for remaining vitamin D deficient (see sections 4 and 6)

**Note this is unlicensed in pregnancy


SAFETY NOTE:  Errors continue to occur due to confusion between monthly, weekly and daily regimes and of high dose supplements being left on repeat prescription. Loading doses for treatment of deficiency and insufficiency should not be added to repeat and stop dates should be added to prescriptions where appropriate.


Record: 3399
Clinical condition:

Vitamin D Deficiency or Insufficiency

Target patient group:
Target professional group(s): Primary Care Doctors
Secondary Care Doctors
Adapted from:

Evidence base


  1. Consensus Vitamin D position statement.
  2. Pearce SHS, Cheetham TD. Diagnosis and management of vitamin D. BMJ 2010; 340: 142‐147.
  3. DOH .
  4. UKMI Q+A What dose of Vitamin D should be prescribed for the treatment of vitamin D deficiency?

Grateful thanks to Dr S Orme, Dr A Abbas and Nicola Butler at Leeds Teaching Hospitals for their invaluable help writing this guideline.

Approved By

Leeds Area Prescribing Committee

Document history

LHP version 2.0

Related information

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