Intravenous injection is the fastest method for a drug to reach the brain because the “drug is delivered into a vein without any intermediary tissue. [...Although the drug reaches the brain extremely fast when injected intravenously, the] principle disadvantage, however, is that the effects of intravenous drugs are irreversible” ( Levinthal, 50). Currently I do not have any "J" words. If you can think of any please let me know! Type request in guestbook! Currently I do not have any "K" words. If you can think of any please let me know! Type request in guestbook! Licit Drugs: Drugs whose manufacture, sale, or possession is legal.