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OPIATES & OPIOID NARCOTICS
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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
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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.