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OPIOIDS
I.
Where do they come from?
– poppy plant: from middle east and Asia
– dried sap from plant is opium; cultivated annually BUT
plant produces drug within only 10 day window
87% of world’s opium comes from Afghanistan
(2005 U.N. report)
– major active ingredient in opium: morphine
/ synthesized in 1803
/ named after the Greek god of dreams Morpheus
/ morphine altered in late 1800s into heroin-a
“heroic” TX
(3-10x as strong as morphine)
/ Fentanyl
OPIOIDS
II.
Medical Uses
– As pain reliever (morphine, demerol, codeine, lortab,
lorcet, percodan, percocet, vicodin, oxycontin)
– with chronic pain or terminal patients
– in some cough suppressants
– treatment of diarrhea, which is dehydrating
OPIOIDS
III. Prevalence
1998: heroin + non-medical use of analgesics
– Lifetime- 6.4%
2001:
H: 1.4%
P: 9.8%
Past Year- 2%
0.2%
3.7%
Current- .9%
0.1%
1.6%
• current users: # significantly increasing
it was estimated that there were 141,000 new users of heroin in 1995
-
rate of new heroin users increasing; 90% are under age 26
and smoke, sniff or snort it rather than inject……stigma?
-
DAWN data: 14% of all drug-related episodes involve heroin
OPIOIDS
IV. Mechanisms of action
• opiates trigger our own brain chemicals,
the endorphins (short for “endogenous
morphine”) to relieve pain
• naloxone reverses and blocks effects of
opiates by blocking opiate receptor sites
OPIOIDS
V. Effects
• produces short-lived euphoria, profound
relaxation, body warmth (lowers body temp)
• tolerance develops rapidly to opiates so
increasing doses is very common
• drug taking becomes a chore to avoid withdrawal
SX - illustrates ? reinforcement
Rats:
heroin
tolerant
Received
injection of
heroin 15
mg/kg in
familiar
environment
Overdose
rate: 32%
Rats:
heroin
tolerant
Received
injection of
heroin 15
mg/kg in
unfamiliar
environment
Overdose
rate: 64%
Received
injection of
heroin 15
mg/kg for first
time
Overdose
rate: 96%
Control
rats: No
heroin
tolerance
To some degree, drug tolerance is associated with
environmental factors. Tolerance may disappear or decrease
if a drug is used in an unfamiliar environment.
A diagram of Siegel’s rat experiment
OPIOID WITHDRAWAL
• Stoppage (or reduction] in opioid use that has
been heavy and prolonged (several weeks +)
• OR administration of opioid antagonist after
period of use
• Symptoms include: (need at least 3 for DSM criteria)
–
–
–
–
–
–
dysphoric mood
diarrhea
muscle aches
insomnia
nausea or vomiting
runny eyes or nose
- yawning
- fever
- dilation of pupils, piloerection
or sweating
OPIOIDS
VI.
Treatment
- methadone TX: peak concentration occurs 2-4 hours
after taken, in contrast to effects of other opiates
which kick in right away like a hammerblow;
metabolites of methadone are inactive, unlike other
narcotics
- blood levels of methadone, when given orally, is below
ED level in tolerant patients, and is safely above the
threshold for withdrawal...so, methadone combines
safety and long action
-
LAAM, naltrexone, buprenorphine
-
TCs
OPIOIDS
• Needle exchange programs to prevent HIV:
are you pro/con?
• Should heroin be given to terminal
patients? Do terminal patients have right to
die with drugs?
• Should non-terminal pain patients be
freely medicated with morphine or even
stronger painkillers?
OPIOIDS
• Morphine treatment for pain generally
given to 2 groups of patients:
– post-surgery patients receive it on short-term basis
– cancer and burn victims given it for much longer
durations (typically given IM or under the skin)
What about potential for addiction?