It is not good idea to buy drugs using bitcoin. Because drugs is illegal and some states in tje US does not prohibit it and of you want to buy then try browsing deep web and download tor browser. But im telling you not to buy drugs using bitcoin.
I think this would be a big blunder from ones side if he buys drugs from bitcoin because drug can be easily bought by doing some extra work or a part time job but using Bitcoin for drugs will put the person in loss when he will get to know that the price of Bitcoin increased more. But I think that the drug addict would not care about the Bitcoin as he needs drugs daily to provide his body a sense of calmness and pleasurable feelings.
In some countries, drugs activity is illegal and you can be catched by the police if use or buy/sell it.
Example my country, have a payment method to keep safe and anonymous activity in criminial activity as Bitcoin is neccessary.