Loading dose of 300,000 IU of vitamin D does not last long – March 2014

Is the response to high dose oral vitamin D replacement predictable?

Society for Endocrinology BES 2014 – Liverpool UK, March POSTER
Deepak Chandrajay, Marina Milic, Gwen Al-Khaili, Afroze Abbas & Stephen Orme

In our institution, an observed loading dose of oral colecalciferol (D3) 300 000 units is used for treatment of vitamin D deficiency (Vit D <30 nmol/l), with subsequent re-evaluation at 6 weeks and 3 months. We evaluated the follow-up of all the patients who received loading dose colecalciferol against adherence to this protocol.

Method: All patients who received observed loading dose of colecalciferol for a 1-year period were included. Demographic, clinical, and biochemical data was collected from existing databases and clinical notes.

Results: A total of 256 patients had observed loading dose colecalciferol (female 179 and male 77). The age range was 18–91 years old. The median age was 54.62 years. Basal Vit D at time of loading ranged between <20 and 43.5 nmol/l.

Vit D was repeated at 6 weeks and 3 months, as per protocol in only 63 and 48% of cases respectively. Of those who did have Vit D rechecked at 6 weeks, 87% (n=140/161) improved their Vit D concentration >50 nmol/L, 9.3% (n=15) had levels between 20–50 nmol/l and only 3.7% (n=6) had Vit D <20 nmol/l. Vitamin D concentrations fell to <50 nmol/l in 48% (74/154) of the patients within 12 months.

18.75% (n=48) patients required oral reloading within 12 months and seven were switched to i.m. ergocalciferol. Four of these patients were known to have malabsorption problems. There was no correlation between BMI and the response to high dose Vit D or need for further oral reloading. There were no episodes of toxicity or adverse events. There was no significant hypercalcaemia.

Conclusion: Observed loading dose colecalciferol was safe and efficacious in this heterogeneous group of patients. Problems with adherence to the protocol were identified which led to need for reloading in a large group of patients. BMI had no impact on response to high dose Vit D.


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See also VitaminDWiki

Overview Loading of vitamin D contains the following

Loading dose: 200 studies at VitaminDWiki

Vitamin D loading dose (stoss therapy) proven to improve health overview
If a person is or is suspected to be, very vitamin D deficient a loading dose should be given

  • Loading = restore = quick replacement by 1 or more doses
  • Loading doses range in total size from 100,000 IU to 1,000,000 IU of Vitamin D3
    • = 2.5 to 25 milligrams
  • The size of the loading dose is a function of body weight - see below
    • Unfortunately, some doctors persist in using Vitamin D2 instead of D3
  • Loading may be done as quickly as a single day (Stoss), to as slowly as 3 months.
    • It appears that spreading the loading dose over 4+ days is slightly better if speed is not essential
  • Loading is typically oral, but can be Injection (I.M,) and Topical
  • Loading dose is ~3X faster if done topically or swished inside of the mouth
    • Skips the slow process of stomach and intestine, and might even skip liver and Kidney as well
  • The loading dose persists in the body for 1 - 3 months
    • The loading dose should be followed up with on-going maintenance dosing
    • Unfortunately, many doctors fail to follow-up with the maintenance dosing.
  • About 1 in 300 people have some form of a mild allergic reaction to vitamin D supplements, including loading doses
    • it appears prudent to test with a small amount of vitamin D before giving a loading dose
    • The causes of a mild allergic reaction appear to be: (in order of occurrence)
    • 1) lack of magnesium - which can be easily added
    • 2) allergy to capsule contents - oil, additives (powder does not appear to cause any reaction)
    • 3) allergy to the tiny amount of D3 itself (allergy to wool) ( alternate: D3 made from plants )
    • 4) allergy of the gut to Vitamin D - alternative = topical
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