i need at least 500mg oxycodone IVed to get by. so 8mg bupe won't touch me. i'd need 16mg i think, but there's a ceiling dose, right?
this is not "that" high. oxycodone is about the same strength as morphine when injected intravenously. i know people who inject 600, 800, 1000, 1200, 1600 and even 3200mg morphine PER DAY I.V.! i am not kidding. this is no joke. 3,2g of pure morphine-sulphate-pentahydrate. yes.
i also know someone who needs to take at least 400mg oxycodone intravenously to feel it. i take 80mg per shot. i take two shots when i'm shooting, then i wait about 6 hours, then again.
edit:
ontopic: yes, opiates have their receptors: µ, ∂, kappa,... these receptors are categorized into some more receptor-types. µ1,µ2 and even µ3 and so on...
i know what the OP means. when i'm on heroin/morphine, oxycodone barely substitutes the heroin/morphine. but when i'm on oxycodone, morphine/heroin works well to kill the withdrawal. it seems like morphine being a "wider" full-agonist than oxycodone, at least for me. oxycodone has the worst withdrawal though, speaking of myself. it was worse than morphine and heroin. pure hell.