Vitamin D Prevention and Treatment of Deficiency in Adults 

This guidance gives a summary of how to treat adults who are at risk of or who are known to have deficient / insufficient levels of vitamin D. It is based on full guidance located on NHSGGC StaffNet / Clinical Info / Clinical Guideline Directory (link only active if accessing via NHS computer) and search for "Vitamin D Prevention and Treatment of Deficiency in Adults". 

Introduction

Deficiency of vitamin D can result in osteomalacia. The prime aim of vitamin D supplementation is to prevent this vitamin D deficiency syndrome and the long-term consequences of it i.e. osteoporosis and increased fracture risk.

In the asymptomatic general population there is no need to measure vitamin D levels although supplementation may be considered. Refer to flowchart 1 from the NHSGGC guideline, Vitamin D Prevention and Treatment of Deficiency in Adults, for advice on supplementation in the general population.

Assessment and Monitoring

When to Measure Vitamin D

• In patients with low serum adjusted calcium (<2.1mmol/L) and/or where other blood results suggest possible osteomalacia (see below)
• Patients with malabsorption syndromes
• CKD (eGFR <30ml/minute/1.73m²) - measurement of vitamin D in this context should usually be carried out by specialist clinics only.

Follow up measurements are rarely required – seek specialist advice before requesting.

Signs and Symptoms of Osteomalacia

Osteomalacia is clinically characterised by joint and bone pain and is associated with abnormal biochemistry as follows:

• high serum alkaline phosphatase 
• low/low normal serum calcium 
• high plasma parathyroid hormone
• low serum vitamin D, usually <25nmol/L.

Drug Therapy/Treatment Options

For recommended treatments and dosage regimes in patients with, or at increased risk of, osteomalacia, osteoporosis or increased risk of fracture please refer to flowchart 2 from the guideline, Vitamin D Prevention and Treatment of Deficiency in Adults, on NHSGGC StaffNet / Clinical Info / Clinical Guideline Directory (link only active if accessing via NHS computer). Wherever possible, licensed products should be used in preference to unlicensed preparations. For available licensed colecalciferol preparations see table here.

Loading Doses

For patients requiring a loading dose of 300,000 units this can be given as a single dose orally or intramuscularly (IM preparation is unlicensed), but may also be given using one of the following oral regimes (as per Royal Osteoporosis Society Guidance "Vitamin D and Bone Health"): 

• 50,000 units weekly for six weeks or
• 40,000 units weekly for 7 weeks or
• 4000 units daily for 10 weeks.

Maintenance Doses

Where daily supplementation is recommended, the patient can be offered a weekly or twice weekly regime which provides approximately the same total daily dose if preferred.

Calcium and Vitamin D supplementation

From flowchart 2, if a combined calcium and vitamin D preparation is recommended then consult the NHSGGC Adult Formulary for choice.

Content last updated October 2019.