Drugs of Pain Relief Flashcards
Lecture Outcomes
1) Describe key steps and processes involved in opium production
2) List significant historical and scientific events throughout the discovery,
development, and human use of opium
3) Describe the action of morphine on the human body and the main receptor
involved
4) Describe the harmful effects accompanying morphine abuse, the modern opioid
epidemic and its impact on society and individuals
5) Discuss the challenges involved in finding a balanced approach to opioid use
Aim of Lecture
To explore the historical and
scientific factors surrounding
the discovery and human usage
of the powerful pain-relieving
drug morphine.
History of Morphine – the Oldest Drug?
Derived from resin of opium poppy (papaver somniferum)
Distinct from common poppies
Long history of human usage
2100 BC
Sumerian clay tablet, one of the oldest lists of prescription
medicines
Hul Gil, the ‘joy plant.’
1500 BC
Greek statue with poppy seeds in hair and closed eyes
suggesting sedation
300 BC to 100 AC
Recommended for use before surgery by Greco-Roman
physicians such as Theophrastus, Celsus, Galen
History of Morphine – Modern
Harvesting Opium – A Specialist Task
Wait 2 weeks after petals fall
When pod turns dark & crown sticks up it is
lanced with a special knife (3-4 blades – cut
1-1.5 mm)
Timing on the day is crucial & resin or sap
is allowed to seep overnight
Pharmacological activity takes a few hours
to emerge
Wait for sap to turn brown & sticky
Scraped using a blunt knife (up to 5-6 times)
History of Morphine – Heroin
1874
Heroin - diacetylated morphine
Invented in a UK pharmacy (Wright)
Distasteful to his dogs!
1897
Felix Hofmann prepared heroin at
Bayer (German company)
Heinrich Dreser fanatically promoted
heroin as safe alternative to
morphine
Widely sold OTC in USA, Europe, etc
(e.g., cough mixture, “soothing syrups” for
children)
History of Morphine – The Opium Wars
17th Century - British took control of Indian
opium-producing areas
1750 - Opium became main commodity of
British trade with China (1767:2000 chests/yr)
1839-1842 (First Opium War)
Begins after Lin Zexu, a Chinese commissioner,
confiscates illegal foreign opium imports
(Britain sent warships in response)
1856-1860 (Second Opium War)
Britain & France vs. China
Early 20th C
Heroin Products
(USA)
soothing syrup
History of Morphine – Military
1843
Dr Alexander Wood (Scottish) invents
hypodermic syringe
Pioneers i.v. morphine use (his wife fatally
overdosed!)
1859-1865 (US Civil War)
≈ 400,000 troops opium addicted
“The returning veteran … had a leather thong around
his neck and a leather bag (with) Morphine Sulfate
tablets, along with a syringe and a needle issued to
the soldier on his discharge…This was called the
“Soldier’s Disease.” (Gerald Starkey)
History– The Opium Craze
17 and 18th Century Britain, etc
Opium mainly prized for its analgesic effects
(presurgical and pre-antibiotic era - many people
lived with chronic painful ailments)
High prevalence of tuberculosis (painful lung condition
– opium helped control pain)
Also, toothache (widespread before modern dentistry)
Its euphoric effects also made opium popular
for recreational purposes
Especially among elites - literati, intellectuals
1821, Confessions of an English Opium Eater, Thomas
de Quincey
Types of Opioid Receptors photo
The Scale of 18th C Indian Opium Production [Dormandy (2012)]
it was fucking high
19th C British Parliamentarian – William Wilberforce
Pioneering antislavery politician, social
activist, philanthropist (1759-1833)
1807 passage of his antislavery Bill “one of
the turning events in the history of the
world”
Took opium for 45 years (addicted)
Struggled with its hallucinatory powers
and its depressions
Took opium before addressing British
House of Lords
”To that I owe my success as a
public speaker.”
Types of Opioid Receptors
Inhibitory G-protein coupled receptors – contain around 400 amino acids and
7 transmembrane domains
3 major classes (90% of amino acids are identical in each)
Heroin History – The US Experience
Early 20th century – major US epidemic
1914, Harrison Narcotic Act (federal
regulation and taxation of opioids)
New York, 1915 -1920s, heroin black
market began (compact drug)
Emergence of i.v. heroin abuse
Addicts began collecting & selling scrap
metal (“junkies”)
1922: NY, heroin linked to 260 murders
1924, Congress banned heroin production
The Science of Morphine: Pain Relief
Morphine is the prototypical opiate and
our best analgesic (pain-relieving drug)
Binds to opioid receptors in brain & spinal
cord (strong agonist)
Inhibits transmission of pain signals
from periphery
↓ brain’s perception/awareness of pain
Also causes euphoria (contentment &
wellbeing - major reason for abuse)
This is different to analgesic NSAIDS (e.g.,
aspirin, ibuprofen) that suppress the
production of pain signalling molecules in
inflamed tissues (e.g. prostaglandins)
Opioid Receptors are Mainly Located in the CNS, GI-Tract and
Nerve Endings in Peripheral Tissues
Opioid Addiction
Definition: Compulsive use of drugs for
nonmedical reasons; it is
characterized by a craving for mood
altering drug effects, not pain relief.
Morphine and related drugs have very high
addiction potential:
Physical dependence and tolerance occur readily (i.e.
user needs higher doses to achieve euphoric
response)
Also a high capacity for psychological dependence
Withdrawal symptoms can be incapacitating
(but rarely fatal)
Opioid addiction is damaging to individuals,
families, communities, etc
Societal attitudes swing between libertarianism and
prohibition
Morphine Mimics the Effects of Naturally-Occurring Endorphins
Endorphins (from endogenous & morphine) =
small neuropeptides
Made in CNS by controlled digestion of protein
precursor (pre-POMC)
Released during pain, pleasure & stress
An important family member is β–endorphin
Agonist at µ- & δ-opioid receptors
Suppress pain transmission but also cause
euphoria (e.g., exercise, etc)
Short duration of effect
Quickly broken down by metabolism
Morphine has longer a duration of action
morphine side effects
Chemists have Created many Morphine-like Narcotic Analgesics photo