Methylcobalamin 5000 mcg is a high dose of vitamin B12 used for conditions such as nerve damage or confirmed deficiency. Vitamin B12 is water soluble and is not known to harm the kidneys or increase creatinine levels, even when kidney function is mildly reduced. A creatinine level of 1.52 mg per dL may suggest reduced kidney function, but it should be interpreted along with eGFR and clinical context. Since this is a high dose and may not be necessary for everyone, it should only be taken if prescribed by a doctor after proper evaluation of your kidney function and overall health.