Can I get admitted to Master in mathematics program if I only have a medical degree?
The question is whether you have enough background to be likely to pass the first-semester courses in such a program.  For instance, if you have never studied real analysis, complex analysis or differential equations at the level of a senior undergraduate course, you may find yourself completely lost in graduate courses.  I think it will be very difficult to convince an admissions committee that you would survive the first semester.