Yes, I have been on 40,000 IU unit/day for over a year and tolerated it very well. I didn't have any relapses until I started to reduce the dosage to 30,000 IU/day which is when I began having these issues. This could be a coincidence and maybe not.
But I would agree that taking this much Vitamin D is not reccommended by anyone in the medical comunity. However, if you read the data published on what the upper level of Vitamin D is that cause hypercalcemia it seems that the dosage would be much greater than 40,000 IU/day.
Incidentally, here is a Phase I study in which people were put on an escalating dose of Vitamin D to a maximum level of 40,000 IU/day with an average of 15,000 IU/day for a year:http://www.ncbi.nlm.nih.gov/pubmed/20427749
There was no evidence of hypercalcemia or any ill effects due to vitamin D.
Likewise, here is another Phase I trial of high dose vitamin D (20,000 IU/day for 12 weeks):http://www.ncbi.nlm.nih.gov/pubmed/21179201
Again, no indication of hypercalcemia or any ill effects due to Vitamin D.
Here is a good video presentation of Vitamin D and toxicity by Dr. Reihold Vieth who is a leading scientist on Vitamin D:http://youtu.be/MIDWA9-cGdY
In this video he describe a case of a man who was poisoned by his wife with 1.7million IU/day for 7 months. The man survived and is fine.
Finally, here is a review of the safety of vitamin D by looking at all known past cases of people who have taken massive doses of vitamin D by accident:http://www.grc.com/health/pdf/Vitamin_D_Supplementation_25-hydroxy_D_concentrations_and_safety.pdf
So, you can see from the chart above, it takes a lot of vitamin D supplementation over a long duration of time before you start experiencing negative effects.
All of the reports of vitamin D toxicity showing the convincing evidence of hypercalcemia involve serum 25(OH)D concentrations well above 200
nmol/L (Table 5), which requires a daily intake of ³1000 mg (40 000 IU), and which could thus be conservatively considered the LOAEL (Lowest Observed Adverse Effect Level).
So, there really is no evidence that this level of Vitamin D is going to cause any adverse effects. Because of this, I was willing to give it a try to see if it helped me.
Incidentally, the Institutes of Medicine recommends the daily intake should be 600IU/day. This is reccomendation and all of the previous reccomendations are only to prevent rickets and it probaly dooms a lot of people to become afflicted with MS in the first place.http://www.grassrootshealth.org/_download/scientists'%20letter%20050508.pdf