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OPIATES & OPIOID NARCOTICS
http://www.pharmainfo.net/files/u4145/Morphine.jpg
http://www.aurorawdc.com/ci/oxycontin.jpg
Definitions
Opiates: drugs naturally found in opium (morphine
and codeine)
Opioids: exogenous substances, natural or synthetic,
with properties similar to opium
NARCOTICS: another term for opioids
This term was originally conceived to refer to substances
that induce “narcosis” or sleep.
This term has been used more loosely in the legal
profession to refer to all illicit drugs.
Technically, many of these drugs (e.g., cocaine, marijuana)
are not narcotics according to the original definition of this
term.
Early History of Opium
Papaver somniferum
Early Egyptian and Greek cultures
India and China
Opiate Dependence
19th Century Writers and Opium
The Opium Wars
Started by outside incidents
Britain given the island of Hong Kong for winning
19th Century Discoveries
Morphine isolated and named by Sertürner, 1806
Codeine isolated in 1832
Hypodermic syringe developed in 1853 by Alexander
Wood
Heroin synthesized in 1874, marketed in 1898 by
Bayer Laboratories
http://www.pharmainfo.net/files/u4145/Morphine.jpg
Photo from erowid.org
History of Opioid Use
Before the Harrison Act
Oral opium use common, patent medicines
~ 1850, Chinese introduced opium smoking to U.S.
After 1850s, morphine administered by injection
1898, heroin introduced
After the Harrison Act
Number of oral opium users declined
I.V. heroin injection became more common form
of use among recreational users
History of Opioid Use
20th Century Developments
Changing population of opioid users
1960s
Vietnam and heroin use
1970s-1980s
Current heroin use
Abuse of prescription opioids
Neuropharmacology of Opioids
Opioid Receptors
Mu, Kappa, Delta
Endogenous Opioids (Endorphins)
Enkephalins, Dynorphin, Beta-Endorphin
The activation of opioid receptors blocks the
transmission of pain signals from the spinal
cord and brain stem.
Opioid Antagonists
Naloxone
Naltrexone
Some Synthetic Opioids
methadone (Dolophine)
meperidine (Demerol)
oxycodone (Percodan)
oxymorphone (Numorphan)
hydrocodone (Vicodin, Lortab)
hydromorphone (Dilaudid)
propoxyphene (Darvon)
pentazocine (Talwin)
fentanyl (Sublimaze)
Medical Use of Opioids
Clinical Uses
Analgesics (pain relief)
Antidiarrheals (constipating effects)
Antitussives (cough suppressants)
Side Effects
Drowsiness
Respiratory depression
Nausea, vomiting, and constipation
Inability to urinate
Drop in blood pressure
Tolerance/Dependence
Physicians frequently under-prescribe narcotics,
in fear of causing dependence.
Tolerance and Dependence
with Opioids
Tolerance
begins with initial use, but not clinically
evident until 2 to 3 weeks of frequent use.
occurs most rapidly with high doses given in
short intervals.
Physical dependence
invariably accompanies severe tolerance
Psychological dependence
common with frequent narcotic use
Effects on Human Behavior
Subjective Effects (from anecdotal reports)
Opium was commonly used among 19th century
literary figures and artists.
Effects depicted as euphoric, vivid dreamy, trancelike state.
Systematic Studies on Mood
Initial positive mood changes (anxiety reduction,
euphoria), but continued use produces more
negative mood states, social isolation, and
aggression.
Subjective effects differ between experienced and
naïve users.
Experience of pain influences subjective effects.
Effects on Human Behavior
Performance
In naïve subjects, opioids can slow performance
on psychomotor tasks; cognitive performance is
less impaired.
Tolerance develops to these effects in chronic
users.
People can maintain good health and productive
work for extended periods of opioid use.
Detrimental effects of opioids on performance
are diminished when people are experiencing
pain.
Behavioral Effects In Nonhuman
Laboratory Studies
Unconditioned Behavior
Morphine has biphasic effects on spontaneous motor
activity.
Low doses increase activity; higher doses decrease
activity.
In rats, higher doses also produce stereotypy, which is
distinct from the type of stereotypy produced by
amphetamine.
e.g., wider range of behaviors, including social behaviors
Behavioral Effects In
Nonhuman Laboratory Studies
Conditioned Behavior
Low doses of opioids increase response rates
under schedules that produce low rates of
responding (e.g., FI schedules) of positive
reinforcement, but higher doses decrease rates.
Low doses increase avoidance responding; high
doses slow avoidance responding without
disrupting escape behavior (like the depressants).
Unlike depressants, opioids do NOT have
antipunishment effects.
Self-Administration
Nonhuman animals readily acquire
morphine and heroin self-administration.
Rates and patterns of self-administration
are similar between humans and monkeys
Daily intake slowly increases over time and
there are no periods of abstinence or voluntary
withdrawal.
This is unlike patterns observed with cocaine
self-administration, involving alternating
cycles of intake and abstinence.
Drug Discrimination with Opioids
Most opioids are readily discriminated by
nonhumans (rats and monkeys).
Stimulus generalization is observed between
morphine and other mu agonists (e.g., heroin,
methadone, codeine).
Partial generalization occurs between mu agonists
and mixed agonists (e.g., cyclazocine).
Stimulus generalization generally not found
between mu agonists and kappa agonists.
Health Risks
Abuse Potential
Subjective and reinforcing effects contribute to
high abuse potential
MU agonists (e.g., morphine, heroin, fentanyl,
hydrocodone, Oxycontin) tend to have a high
abuse potential.
Mixed or partial agonists (e.g., butorphanol,
nalbuphine) generally have low abuse potential.
I.V. Heroin Use and AIDS Risks
Over 50% of I.V. heroin users have been exposed
to the AIDS virus
Opioid Dependence & Treatment
Withdrawal Symptoms (flu-like symptoms)
runny nose, tears,
minor stomach cramps, loss of appetite, vomiting,
diarrhea, abdominal cramps,
chills, fever, aching bones, and muscle spasms
Narcotic Substitution Treatments
Methadone, levo-alpha acetylmethadol (LAAM),
Buprenorphine
Maintaining dependence
Narcotic Antagonist Treatment
Naltrexone
Prevents user from experiencing high if opiates used
Compliance can be problematic.