Is it possible to apply to US university and be admited when you already admitted in another country?

I’m a first year student of Tajik State Medical University named after Abuali ibni Sino (Avicenna University). Located in Tajikistan, Central Asia. I’ve made a mistake in choosing an university. Could you tell me, CAN I apply and be admited to the universities in US now when already studying???. IF no, WHY??? THANK YOU!