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List some opioid drugs; which are used therapeutically, and for what purpose, primarily?
- Opium: was primarily used as an analgesic (pain relieving)
- Codeine: Pain relief
- Morphine: Pain Relieving
- Heroin: cough suppressant and pain reliever
- Heroin, coke, morphine, fentanyl, methadone, meperidine, buprenorphine, nalbuphine, codeine
- Heroin, coke, morphine, fentanyl, methadone, meperidine, buprenorphine, nalbuphine, codeine
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Briefly describe the history of opioid use (and legislation in the U.S.).
- Opium comes from poppy plant, used medicinally and recreationally almost as long as alcohol, 6000BC in Mid-east.
- 1800s-1900s very popular in france, many writers and poets.
- Hypodermic syringe created, pre-civil war. Morphine addiction increased in the US, “soldiers disease” (highest rate of opioid use in US).
- 1914- ban of non-medical use of opium, morphine, coke in the US.
- 1950s-2000s- 600,000 opioid addicts in the US, mostly heroin. Heroin comes from southeast Asia, mid-east, South America
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What are common routes of administration for opioids? Describe differences in pharmacokinetics of the various opioids.
- orally
- i.v.
- inhalation
- intranasal
- transdermal (patches)
The most common routes of administration for is intravenously, inhalation, and intranasally. Heroin is more lipid soluble thus more readily penetrates the blood brain barrier. Excretion of the opiates is fairly rapid with 90% excretion within a day after taking the drug.
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What is the cellular mechanism of action of opioids?
Cellular mechanism of action- opioid antagonist, bind to opioid receptors,mimic endogenous opioid’s nt’s. opioid receptors, high density in spinal cord, hindbrain, PAG, mesolimbic pathway, thalamus and hypothalamus
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Describe the major psychophysiological effects of opioids; what parts of the nervous system are altered that contribute to these effects?
- Acute Psychological effects: analgesia, drowsiness, heavy feeling limbs
- Acute Physiological effects: respiratory depression, lower body temperature, nausea and vomiting occur immediately after taking opiates Pin Point Pupils (pupil contraction)
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Does tolerance develop to all effects of opioids during chronic use? What is cross-tolerance? What are the 3 primary symptoms of opioid overdose?
- Opioid tolerance develops rapidly. Tolerance to analgesic and euphoric effects develop faster than consumption and respiratory depressant effects, no tolerance to pupil constriction.
- Cross-tolerance is tolerance to a drug that has never been taken before due to the consumption of an alike drug.
- 3 symptoms of opioid overdose- stupor or coma, pinpoint pupils, respiratory depression
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Describe the typical withdrawal syndrome from opioids in dependent users. Is opioid withdrawal typically life-threatening relative to withdrawal from others types of drugs (e.g., alcohol)?
- Opioid withdrawl symptoms- depression, irritability, light sensitivity, increased respiration, diarrhea, violent yawning, spontaneous orgasm (men), restlessness, tremors, flu-like symptoms.
- These can begin 6-12 hrs after last dose, peaks 2-3 days and can last 7-10 days, withdrawal not life threatening
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What is the typical pattern of intake in an opioid-dependent person (relative to a methamphetamine/cocaine-dependent person)?
Typical pattern of intake in an opioid dependant person starts out slowly increasing then remains steady, unlike stimulants, more of a crash and binge cycle
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Describe pharmacological treatments used to help opioid-dependent individuals wean themselves from heroin or other opioid agonists. What are the advantages and disadvantages of the various treatments?
- Opioid treatments- replacement therapies: methadone, must be taken daily, w/drawal prolonged
- LAAM (levo alpha acetylmethadol): orally active, lasts 48-72 hrs don’t have to take daily
- Blockade therapies: naloxone, naltrexone, block agonist effects (disadvantages are increasing withdrawal and daily use necessary)
- Buprenorphine “blocks and replaces”, blocks high efficacy agonists(advantages for this are wide margin of safety)
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