My son (12 yo) has been on Dasatinib 70mg for the last year, after having switched over from Imatinib. His Vit D3 levels has been persistently low, which we address through monthly dose of 60k supplement. However, his magnesium levels seem to be rising over the past few months (now at 2.53). From what i have read, low Vit D3 goes together with LOW mg. Combination of low D3 and high mg seems unlikely. His renal functions are fine.
Anyone here has any such experience?
Hi. I was diagnosed with cml in 2015 had similar issues check this out
You’re right to be paying attention to this—your observations are sharp. Typically, low vitamin D3 and low magnesium often occur together because magnesium is essential for vitamin D metabolism. However, in your son’s case, you’re seeing low vitamin D3 and elevated magnesium (2.53 mg/dL), which is somewhat unusual.
Here’s a breakdown and possible explanations:
⸻
Normal Ranges & Your Son’s Magnesium
• Normal serum magnesium: 1.7 – 2.3 mg/dL (values may vary slightly depending on the lab).
• Your son’s level: 2.53 mg/dL – this is mild hypermagnesemia.
⸻
Possible Explanations for High Magnesium
1. Supplementation or hidden sources:
• Is he taking any magnesium supplements, multivitamins, or medications with magnesium (e.g., laxatives like milk of magnesia or antacids)?
• Some protein powders or fortified foods (especially for kids) may contain magnesium.
2. Dasatinib effect:
• While dasatinib typically doesn’t cause hypermagnesemia, tyrosine kinase inhibitors (TKIs) in general can subtly affect electrolyte handling by the kidneys, including calcium, phosphate, and magnesium.
• Renal tubular handling of magnesium might be impaired—not enough to affect overall renal function tests, but enough to reduce excretion of magnesium.
• There’s sparse but occasional mention in case reports of TKI-induced electrolyte disturbances, although hypermagnesemia is rare.
3. False elevation or lab variation:
• If hemolysis occurred during the blood draw (breaking open of red blood cells), it can falsely elevate serum magnesium.
• It’s worth rechecking the value to confirm it’s consistently high.
4. Low Vitamin D and Magnesium—paradox?
• You are correct that magnesium is necessary to convert vitamin D into its active form. Low D3 with high Mg is not common—but:
• The monthly 60,000 IU dose might not be enough, or not well absorbed/metabolized, even if magnesium is present.
• Dasatinib may interfere with vitamin D metabolism or absorption, or affect liver enzyme activity that converts vitamin D.
• Vitamin D resistance or alteration in VDR (vitamin D receptor) expression is also possible under certain medications or chronic disease states.
