Most medical colleges in the US are 4 years in length after university; there are however, some which offer 6-7 year programs right out of high school.
Most US medical schools require the following courses at the university level for admission:
1 year General Chemistry with lab
1 Year Organic Chemistry with lab
1 Year General Biology with lab
1 Year General Physics with lab
1 Year English
Others may additionally require Biochemistry, Calculus, etc. The vast majority of US medical students have a Bachelor's degree when they matriculate into a 4 year program.
I am unsure as to whether you are inquiring about continuing your studies in the US as an undergraduate medical student or as a resident. Both routes are rather difficult although the latter is less difficult than the former. The cost of a medical education in the US varies, but international students are only accepted in any significant numbers at private colleges which generally charge upwards of $20,000 USD per year in tuition. Some schools require international students to set up a trust fund with 4 years of tuition and living expenses because you are not eligible for US governmental aid. Obviously this can be a substantial sum of money.
Bear in mind that the ability to transfer into a 4 year US college of medical education as an upperclassman (ie, 3rd year) will be exceedingly difficult if not impossible for an international, non-US citizen student. Most schools restrict entry to US citizens, those with significant ties to the university or other strong reasons for being at that school.
Because this topic has been discussed at length, I'll direct you to do a search of this forum to find further information on the subject.
Best of luck to you.
