Opiates
OpiumMorphine
The most effective painkiller known is morphine (C17H19NO3H2O),
isolated from the juice obtained from unripe seed pods of the opium poppy.
Apparently morphine changes the perception of pain even when the pain itself is
not much diminished. For this reason, the drug is valuable in medicinal
practices. Unfortunately, it is addictive, and the body builds up a tolerance to
it, so larger and larger doses may be necessary to provide the same relief from
pain. The drug also depresses the function of the brain center that controls
respiration; large doses of morphine (or of heroin, a very similar molecule) can
kill by causing respiratory arrest.
Codeine
An alkaloid drug (C18H21NO3)
derived from opium. A narcotic with effects like those of morphine, codeine is
prescribed as an analgesic, cough suppressant and hypnotic.
Papaverine
A nonaddictive opium derivative (C20H21NO4)
used medicinally to relieve spasms of smooth muscle.