Opiod Analgesics Flashcards
Define Analgesics
Analgesics can be defined as drugs that relieve pain by acting on the CNS or peripheral nerves without majorly affecting consciousness
State the difference between analgesic and anaesthetics.
Both can relieve pain, what differentiates them is that Analgesics does not induce loss of consciousness
while Anesthetics does
State the classification of Analgesics
✓Opioid analgesics aka narcotics
✓Non-opioid analgesics aka non-narcotics
Briefly describe Opiod Analgesics and Non Opiod Analgesics
✓Opioid analgesics aka narcotics:These act in the CNS and are related to the body’s own opiate receptors. Example; Morphine
✓Non-opioid analgesics aka non-narcotics
These also have anti-inflammatory and antipyretic (i.e dever-reducing) properties. They usually act on peripheral nervous system. Examples; Aspirin
Give a well detailed introduction to Opiods
Opium is a dark brown resinous substance obtained from the poppy plant (Papaver somniferum
•Resinous: having the texture or appearance of resin, which is a thick, sticky substance produced by some plants
Opium is made up of various naturally occurring substances called alkaloids, which are classified into two groups based on their chemical structure and effects. These includes
- Phenanthrene Derivatives E.g
•Morphine: which is an Analgesic and which makes up 10% of opium’s total weight
•Codeine; which is an Analgesic and which makes up 0.5% of opium’s total weight
•Thebaine; which is a Non-analgesic And which makes up 0.2% of opium’s total weight
2. Benzoisoquinoline Derivatives
These are generally Non-analgesics. Examples includes
•Papaverine which makes up 1% of opium’s total weight
•Noscapine which makes up 6% of opium’s total weight
Differentiate between Opiods and Opiates
✓Opiates : Naturally occuring Compounds that are derived directly from opium.
✓Opiods: This is a broader term that includes all drugs with morphine-like effects, regardless of their origin (natural, synthetic, or semi-synthetic) and chemical nature.
In order words , if a drug is not derived from opium but is chemically similar to morphine (such as synthetic opioids), it falls under opioids, not opiates.
•Opioids” is the preferred medical term today because it includes both natural opiates and synthetic drugs that act like morphine.
All Opiates are Opiods but not all Opiods are opiates
True or False
True
Opiods are one of the oldest drugs in the world
True or false
True
Define Opioids
Opioids are a class of drugs that derive from
opium poppy plant (i.e opiates recall that all opiates are Opiods) or mimic natural substances found in the opium poppy plant
What are endogenous opiods
Opiods were described as peptides that have morphine-like effects and are produced in the body
Briefly describe a brief history of Opiods
In the mid-1970s, scientists identified peptides within the mammalian brain, pituitary, spinal cord, and gastrointestinal tract that exhibited morphine-like effects.
These peptides were found to be active in small amounts, blocked by the opioid antagonist naloxone, and bind with high affinity to opioid receptors
State the 3 main families of opioid peptides
1.Endorphins
2.Enkephalin
3.Dynorphins
N:B
Nociceptin/orphanin FQ (N/OFQ) is also an opiod peptide but it’s not usually included
Briefly describe Endorphins
There are various types of endorphin, however the most significant Endorphin is β-endorphin (β-END).
•Location: located primarily in the hypothalamus and pituitary gland,
•Receptors: β-END is primarily a µ agonist, but also has δ activity.
• Effects
When injected directly into the brain is 20–40 times a more potent analgesic than morphine
It decreases the release of LH and FSH, and increases the release of GH and prolactin.
The effects of naloxone on these hormones are opposite, suggesting that the system is always active
What are the most important enkephalins
The most important enkephalins are ✓methionine-enkephalin (met-ENK) and ✓leucine-enkephalin (leu-ENK).
State the receptors for which
Met-ENK and leu-ENK have affinity the
Met-ENK has equal affinity for µ and δ sites, while leu-ENK prefers δ receptors
What are the most important dynorphins
The most important Dynorphin are
✓Dynorphin A (DYN-A)
✓ Dynorphin B (DYN-B)
State 7 Functions Of Endogenous Opiods
✓ pain perception
✓ mood
✓pleasure
✓motor behaviour
✓vomiting
✓release of pituitary hormones
✓ gastrointestinal motility
Define Opiate receptors
Opiod receptors are proteins found on the surface of neurons. They act as binding sites for opioid molecules i.e both endogenous and exogenous Opiods
Briefly describe the discovery of Opiod receptors
Discovery
They were first discovered in 1973, leading to the identification of natural opioid-like substances i.e endogenous opiods in the body.These were involved in the regulation of pain.
State some locations of Opiod receptors
✓ Brain
✓ Spinal cord
✓ Gastrointestinal tract and other parts of the body
State the examples of the protein receptors these opiod peptides binds to
Examples of the protein receptors these opiod peptides binds to includes ;
✓Mu (µ) opioid receptor (MOR)
✓Delta (δ) opioid receptor (DOR
✓Kappa (κ) opioid receptor (KOR
✓Nociceptin/Orphanin FQ (NOP) receptor
State some effects associated with the activation of Mu (µ) opioid receptor (MOR)
• Analgesia
• Euphoria
• Respiratory depression
• Pupil constriction (miosis)
• Bradycardia and
• Physical dependence.
• Muscular rigidity
State some effects associated with the activation of Delta (δ) opioid receptor (DOR)
• Spinal-level pain relief i.e they act on receptors
in the spinal cord to cause Analgesia (major
action)
• Respiratory depression
•Affective behavior
• Reinforcing actions of the drug ( see adverse drug effects)
•Reduced GI motility
• proconvulsant
State some effects associated with the activation of Kappa (κ) opioid receptor (KOR)
When activated, they cause
• Analgesia
• Sedation
• Respiratory depression
• Miosis i.e pupil constriction and
• Dependence.
•Dysphoria
• psychomimetic
• Reduced GIT motility
