Yes there are some medical admin courses like MPH or Ph D in public health which do not require USMLE. You can try Ph D in pharmacology as well.But there are requirements for admission such as TOEFL and GRE where you have to excel,But, USMLE is the best way of furthering your medical studies in USA.
Tulasi Sitaula, Professional Engineer, P.E. at Freelancers (1989-present)
Source: Quora Digest