MTW - Vitamin D Guidance

Vitamin D preparations are widely available and cheap to buy over the counter, where patients require maintenance doses if possible encourage the use of over the counter products.

To treat vitamin D insufficiency (>30 - <50nmol/L), doses of 800 - 2000 units daily (or equivalent given intermittently) are required.

In severe deficiency, (levels vitamin D₃ <30nmol/L), much higher doses are needed up to 50,000 units. A total dose of 300,000units of vitamin D is suggested, split into daily or weekly doses over several weeks, (e.g. 50,000 units weekly for 6 weeks given as Stexerol D3^®tablets or InVita D3^® liquid), or 50,000 units daily for 6 days, (unlicensed dose used for inpatients), then...

For maintenance treatment, Adcal-D₃® can be used if dietary calcium is inadequate. If calcium intake is adequate, colecalciferol tablets/capsules can be prescribed; usual dose is 1000 units daily but occasionally higher doses are needed. If switching products from community, then give the nearest dose in units, (e.g 800 units ≈ 1000 units). Adcal-D3® is also prescribed for patients requiring calcium in addition to vitamin D in the management of osteoporosis.

InVita D3® is a high strength liquid vitamin D preparation which is suitable for all ages. It is available in 1ml ampoules for oral administration. Dosage schedules vary according to age and the treatment or maintenance regimen being prescribed. It does not need to be taken daily and this may be an advantage for patients. Adult dose for the prevention of vitamin D deficiency is 25,000 units (1ml) once a month.

Alfacalcidol: patients with severe renal impairment requiring vitamin D therapy should be prescribed alfacalcidol as hydroxylation of calciferol occurs in the kidney.

Ergocalciferol is only for use if the oral route is unavailable