D.3: OPIATES
INTRO: https://www.youtube.com/watch?v=8iaYksFXoZQ (OPIATES – PERIODIC TABLE OF VIDEOS)
UNDERSTANDINGS
- The ability of a drug to cross the blood-brain barrier depends on it chemical structure and solubility in ________ and ________.
- Opiates are natural narcotic ___________ that are derived from the opium __________.
- Morphine and codeine are used as _____________ analgesics. Strong analgesics work by temporarily binding to receptor sites in
the _____________, preventing the transmission of pain impulses without depressing the central nervous system.
- Medical use and addictive properties of opiates are related to the presence of opioid receptors in the brain.
APPLICATION AND SKILLS
- Explanation of the synthesis of codeine and diamorphine from morphine.
- Description and explanation of the use of strong analgesics.
- Comparison of the structures of morphine, codeine, and diamorphine (heroin).
- Discussion of the advantages and disadvantages of using morphine and its derivatives as strong analgesics.
- Discussion of side effects and addiction to opiate compounds.
- Explanation of the increased potency of diamorphine compared to morphine based on their chemical structure and solubility.
NATURE OF SCIENCE
- Data and its subsequent relationships – opium and its many derivatives have been used as a painkiller in a variety of forms for
thousands of years. One of these derivatives is diamorphine.
1. INTRO: STRONG ANALGESICS - OPIUM AND OPIATES (e.g. codeine, morphine, heroin)
- Opium is harvested from the naturally occurring opium ____________.
- The primary active ingredients in opium, _____________ and _____________, occur naturally in the opium poppy.
- Morphine, codeine, and heroin are examples of _____________.
- Semi-synthetic _______________ is a derivative (i.e. synthesized from) ________________.
- ______________ is a totally synthetic opiate.
- Opiates are also known as ______________ analgesics or strong analgesics.
- Strong analgesics block the transmission of _______ impulses by temporarily binding to opioid receptors in the ____________.
- Opiates are used to treat ____________ pain. (e.g., severe injuries, surgical procedures, heart attack, chronic disease)
OPIATE ADDICTION:
- Highly addictive - especially _____________.
- Addicts develop ______________ / “chasing the dragon” scenario
- Heroin is responsible for nearly _____% of all drug-related deaths (e.g. via overdose) around the globe.
- Legal use is banned, or restricted to use by terminally-ill patients, in most countries.
- Withdrawal symptoms occur within 6 to 24 hours for addicts if supply of drug is stopped.
- _______________ is a milder analgesic used to wean addicts off heroin use.
2. EFFECTS OF OPIATES
SHORT-TERM EFFECTS
- induced feeling of ______________
- dulling of _______________
- depress _______________ system
- slow _____________ and ___________ rate
- ____________ reflex inhibited
- ____________ and __________ (first-time users)
- high doses lead to ______ and / or __________
LONG-TERM EFFECTS
- constipation
- loss of _____ drive
- disrupts ____________ cycle
- poor ____________ habits
- risk of AIDS, hepatitis etc. through ___________
needles
- ____________ problems (e.g. theft, prostitution,
job loss)
3. STRUCTURES OF MORPHINE, DIAMORPHINE (HEROIN) & CODEINE
4. POTENCY OF HEROIN COMPARED WITH MORPHINE
CROSSING THE BLOOD-BRAIN BARRIER
-Nonpolar lipophilic cell membranes coat the blood vessels in the brain. Polar molecules do not readily enter the CNS, as a result.
*____ POLARITY OF THE OPIATE = ____ POTENCY
OPIATE
RELATIVE
POLARITY
EXPLANATION / FACTS
*MORPHINE
- ______________ and two ______________ groups make it sufficiently soluble in
water
- low solubility in _____________, lipid-based environment of the _____________
limits its ability to reach ____________ receptors
*CODEINE
(“________-morphine”)
- polarity ______________by replacing the phenolic _____________ group with the
less polar _____________ group (-OCH3)
- readily crosses blood-brain barrier BUT does not bind to opioid receptor because of
the steric effect of the ‘bulky’ ether group
- codeine, however, is __________ metabolized into ______________
- approximately _____ times less potent an analgesic than morphine
- _________ therapeutic window / ____________ potential for abuse
- most widely used opiate in the world
*HEROIN
(“diamorphine”)
- polarity greatly decreased by the substitution of both hydroxyls on the morphine
molecule with ____________ groups
- heroin is _____________ metabolized into morphine
- approximately ____ times more potent than morphine
- synthesized in the same way that aspirin is prepared from salicylic acid and ethanoic
anhydride