Mavenclad Does Not Affect Vitamin B12 Levels
There is no evidence that Mavenclad (cladribine) affects vitamin B12 levels. The provided evidence exclusively discusses metformin's well-established association with vitamin B12 deficiency, not cladribine or any other disease-modifying therapies used in multiple sclerosis.
Why This Question May Arise
The confusion likely stems from the fact that metformin, an antidiabetic medication, is definitively associated with vitamin B12 deficiency 1, 2. However, this is a completely different medication class with a different mechanism of action than Mavenclad.
What We Know About Metformin and B12 (Not Mavenclad)
For context on drug-nutrient interactions that do exist:
Metformin reduces serum vitamin B12 levels by 19-29% compared to controls, with deficiency occurring in 5.8% of metformin users versus 2.4% of non-users 2
The American Diabetes Association recommends periodic measurement of vitamin B12 levels in metformin-treated patients, especially those with anemia or peripheral neuropathy 1, 2
The mechanism involves malabsorption due to bacterial overgrowth and disruption of calcium-dependent ileal receptors 1
Clinical Bottom Line for Mavenclad
Routine monitoring of vitamin B12 levels is not indicated for patients taking Mavenclad based on available evidence. If a patient on Mavenclad develops symptoms suggestive of B12 deficiency (fatigue, peripheral neuropathy, cognitive changes), investigate other causes including: