Either benzos or opiates. Mind you both are very addictive and have terrible withdrawal symptoms, esp. benzos. It also depends if you already have a tolerance to one of the two or hopefully not both.
If you have a tolerance to opiates i would say use a intermediate acting benzodiazepine like valium or xanax. They both have quick onsets of action and the plus with Valium (diazepam) is that it has an incredibly long half life due to its metabolites and it retains the best muscle relaxant properties of all the benzos, which i think helps with a coke comedown. Clonazepam (klonopin) would also be a good choice because it has muscle relaxant qualities and also has a nice half life, though no were near that of diazepam. Finally i might suggest lorazepam aka ativan as it also is an intermediate benzo and will help as well. In my experience the best benzos that work for me are clonazepam and xanax (in that order). Though clonazepam takes about 1 and a half hours to peak i have to time it out and take it when i know that at about the time it reaches peak blood levels is when i will be out of coke, which is extremely hard to do lol.
Now if you have a tolerance to benzos then i would suggest trying to get some hydrocodone and take around 15-20mgs if weight is between 90 to 125lbs. If weight is 126 to 175 i would begin with 20 to 25. it also depends on your sex as well as Genetics. I am keeping the dosages low to prevent someone from overdosing, as this is a harm reduction site. If you cant get hydro but can get oxycodone and for the sake of not writing an essay i will assume OP is male, I would take 15 to 20 mgs. I would stay away from heroin unless you trust your source and the purity he or she is claiming. If its fairly good a nice small line will suffice. Any other pharms like hydromorphone (dilaudid), to Oxymorphone (opana) are all more and more potent in a sense of weight to potency. They also depend on ROA and i would recommend swallowing only, as pills are meant to be in the first place.
To sum up lol, and i know you are done with the whole drug thing which is great, is the potency of cocaine. Good cocaine wont actually make you fiend for it to the point of doing something stupid. It produces a euphoric uplifting high in which you want to either conversate if with friends, or do something and do it damn well lol. They dont call it Peruvian Marching Powder for nothing lmao. GOOD SHIT stopping the yayo. Not the greatest thing for the heart. As for Opies and Benzos plz stay away, they trouble in the long run if once again you have an addictive personality, which it seems you dont. You are the lucky few, pce bro
