Euphorics - Natural Products Chemistry: Sources, Separations, and Structures - page 86

8.5 HEROIN
Chemically, morphine can easily be converted to diacetylmorphine, known as her-
oin. Heroin is approximately 1.5 to 2 times more potent than morphine weight for
weight due to its lipid solubility. Also, due to this lipid solubility, it is able to cross the
blood-brain barrier faster than morphine. The drug is converted back to morphine by
enzymes in the body before it binds to opioid receptors. These receptors are located
in many areas of the brain, and affect the perception of pain and reward. Opioid
receptors are found also in the spinal cord and digestive tract. However, heroin is an
illicit narcotic drug.
8.6 MEDICAL USES OF MORPHINE
Morphine is used to relieve severe or agonizing pain and suffering by acting directly
on the brain. The endorphins are released in response to pain, strenuous exercise, or
excitement. In clinical settings, morphine exerts its principal pharmacological effect
on the brain. Its primary actions of therapeutic value are to reduce pain and make
patients sleepy.
HISTORICAL NOTE
Ancient peoples either ate parts of the poppy flower or converted them into
liquids to drink. By the 7th century, the Turkish and Islamic cultures of
Western Asia had discovered that the most powerful medicinal effects could
be obtained by smoking the poppy's congealed juices and the habit spread.
Whereas Indians ordinarily ate opium, the Chinese mixed Indian opium with
tobacco and pipe smoking was prevalent throughout the region.
Due to the work of Paracelsus (1490-1541), laudanum (“something to be
praised”) was created by extracting opium into brandy. By the 19th century,
vials of laudanum and raw opium were widely available in England and served
as a medicine, not a drug of abuse. The Bayer pharmaceutical company in
Germany maintained a large heroin production, as the use of opium for medi-
cine was still legal. Its use became widespread with the development of the
hypodermic syringe to allow the injection of pure heroin. There was also heavy
use of morphine in the United States by injured soldiers after the Civil War.
At the beginning of the 20th century, morphine addiction became well
understood and regulations were introduced to curtail opium as an over-the-
counter medicine. Even so, the medical profession remained largely unaware
of the potential risk of addiction for years until they noticed their patients were
consuming inordinate quantities of heroin-based cough remedies. Opium was
not the miracle cure and finally by 1913, Bayer halted production. Finally, mor-
phine became a controlled substance in the United States under the Harrison
Narcotics Tax Act of 1914.