I am not sure which antiseizure drug is blocking your calcium. Not sure what your dexa levels are or if you have fractured. Nor am I sure if your doctor is monitoring your vit d levels, test to monitor calcium levels, or markers of bone formation. If all of this is being done then the best question is why was the problem not caught and what else needs to be done to monitor and keep me safe.

Just some background on the condition:
It is my understanding that these medicines accelerate the liver's metabolism of Vitamin D, reducing its active levels. Since active Vitamin D is essential for calcium absorption in the intestines, this leads to lower calcium levels, triggering bone resorption (calcium withdrawal from bones) to compensate.

A higher amount of vitamin D is usually prescribed to offset this problem.
Plus, Key Tests to Monitor Levels:
Serum 25-hydroxyvitamin D [25(OH)D]: The standard test for measuring Vitamin D deficiency.
Serum Calcium & PTH: To monitor calcium balance.
Bone-specific alkaline phosphatase (bALP): A marker of bone formation.

Vitamin D, whether from food, sun, or drops, must undergo 25-hydroxylation in the liver to become 25(OH)D, and then activation in the kidneys. The issue with Antiseizure medications is that they speed up this liver metabolism too much, breaking down 25(OH)D faster than it can be used. Therefore, higher doses of oral vitamin D are required to compensate for this accelerated metabolism.