We don't say "using A dope" because DOPE is uncountable. We say USING or TAKING DOPE. But that's somewhat archaic now - it's from the hippies in the 60's and 70's. Now we say DOPING when we refer to athletes taking performing enhancing drugs. Nowadays we just say TAKING DRUGS for использование наркотика.

https://books.google.com/ngrams/graph?content=taking+dope%2Ctaking+drugs%2C+using+dope%2C+using+drugs&year_start=1800&year_end=2000&corpus=15&smoothing=3&share=&direct_url=t1%3B%2Ctaking%20dope%3B%2Cc0%3B.t1%3B%2Ctaking%20drugs%3B%2Cc0%3B.t1%3B%2Cusing%20dope%3B%2Cc0%3B.t1%3B%2Cusing%20drugs%3B%2Cc0

Thanks!

My pleasure!

О, я как-то не задумывалась, откуда взялось русское слово "допинг", хотя оно явно английского происхождения. Спасибо, Ули!