Tolerance develops quicky so that huge doses may be taken. This also encourages cyclic use. The tremendous boom in use has made pharmacologists work like mad to characterize the effects and toxicities. It is very difficult to work with as it is carried by protein, is heavily metabolized into a large number of products and the pure oil is unstable in air. It has been classified by some as a sedative-hypnotic with only mild tolerance development.
Smoking increases blood concentrations almost as fast as injections.
X. Inhalents Nitrous oxide, chloroform, ether, gasoline, methyethylketone, a variety of organic solvents act like general anesthetics. Toxicities include free radical formation, cancer, liver damage, etc. Benzene is its own little toxicological gem. Rohypnol is a drug manufactured and prescribed in Europe and Latin America. It is not an approved drug in the U.S., but is smuggled in illegally.