Whenever a vitamin D level of less than 50 nmol/L is discovered there should be a review of the patient’s past medical history including drug history. The BMI should be measured as well as checking renal function (including urinalysis for nephrotic syndrome), calcium and phosphate, liver function, thyroid function, full blood count, ferritin, ESR and CRP. The medical history should consider the possibility of autoimmune disease as well as malabsorption and if appropriate tests for these conditions should be undertaken as well. A PTH level should be considered according to calcium levels.
Treatment should be Colecalciferol (vitamin D3) unless the patient is a vegan when Ergocalciferol (vitamin D2) can be used. Vitamin D3 is available as Fultium-D3 capsules at either 800, 3,200 or 20,000 IU (N.B. excipients include peanut oil). Vitamin D2 is available as either 10,000 or 50,000 IU tablets.
If the vitamin D level is less than 30 than a fixed loading dose of 300,000 IU over 6 – 10 weeks should be prescribed. Schedules may be according to patient preference as daily 4,000 IU for ten weeks, once weekly 50,000 IU for six weeks, or twice weekly 20,000 IU for seven weeks. This should be followed by 1,000 IU daily for life although this should be discontinued if the patient is breastfeeding.
If the vitamin D level is 30 – 50 nmol/L then the dose is 1,000 IU daily for life without a loading dose.
The management in chronic renal failure or severe liver disease or in the presence of an elevated parathyroid hormone should be with specialist assistance.
The parathyroid hormone should be checked six months after starting treatment.
The dietary calcium intake should be calculated and addressed by diet using the calculator available at www.cgem.ed.ac.uk/research/rheumatological/calcium-calculator. If dietary change is not possible then a supplement should be given but this should not be Calcichew D3.
All residents in the UK are currently advised to take a vitamin D supplement of 400 IU daily.
Dr Sophia Khalique