10 - CNS Depressants Flashcards
What are the effects of CNS depressants?
- slow brain activity
- calm and soothe -> decrease anxiety, panic attacks & seizures
- treat insomnia
Name five examples of CNS depressants
Alcohol
Cannabis
Benzodiazepines
Opioids
GHB
What do analgesics do?
Distort sensory perception, emotion, judgement and thinking
What is the main effect of cannabinoids?
Decrease pain
What do hallucinogens do?
Cause hallucinations
Change perception & awareness
Cause psychotic-like behaviour
What does THC stand for?
Delta tertrahydrocannabinol
What is THC responsible for?
Mind altering affects of cannabis
- Euphoria
- Heightened senses
- Relaxation
- Increased libido
Is THC water or lipid soluble?
High lipid solubility (allows for passive diffusion across cellular membranes)
What are the side effects of THC?
Physiological & neurological
Increased HR
Increased pain tolerance
Induces cell-death
Shrinks neurons
Causes DNA fragmentation in hippocampus
What are endocannabinoids?
NT that is naturally produced by body
How do endocannabinoids work on the synaptic level?
- Bind to cannabinoid receptors on neurons producing/facilitating release of GABA
- Inhibit GABA, preventing GABA from inhibiting dopamine production -> increased dopamine production
How does THC work on the synaptic level?
- Has similar structure to endocannabinoids
- Competes with endocannabinoids & binds to cannabinoid receptors
- Inhibits & reduces GABA production -> increase in dopamine
What are the long-term effects of THC on the brain?
- THC binds to various endocannabinoids throughout the brain
- Results in alteration to brain communication with body -> affects emotions, movement, memory, decision making
- Frequent use in adolescence rewires brain, can lower IQ and cause addiction
What are the different cannabinoid receptors and where are they located?
CB1 - Hippocampus, cerebellum, striatum
CB2 - Peripheral tissues - spleen
Where can THC be detected and for how long?
t1/2 in fats - 8 days. detected days-weeks
Urine - infrequent 3-4 days, heavy 10 days, chronic/high fat% up to 30 days
Blood - 2-3 days, heavy up to 2 weeks
Saliva/Oral fluid - 2-24 hours
Hair - up to 90 days
Name the presumptive tests for THC
- DL (Duquenois-Levine) - Violet/black
- Fast blue B - red/blue
- Microscopy - identity confirmation for bulk samples
Opioids are CNS depressants and analgesic’s. True or false?
True
How many alkaloids are in opium? Give an example
20+
Morphine
What is the route of pain?
Nocicereseptors respond to potentially damaging stimuli
Nocicereceptors stimulated -> release excitatory NTs -> signals send to thalamus -> pain perception -> somatosensory cortex -> feel pain
What are the different opioid receptors?
Mu, delta, kappa
What are the two variations of mu receptor?
u1 - analgesia
u2 - respiratory depression & constipation
What shape is the structure of opioids?
T shaped
What are the identifying groups in opioids?
Phenolic group
Aromatic ring
Amine group
What is the t1/2 of morphine?
2-4 hours
What is morphine’s affinity at each opioid receptor?
Mu & delta - high affinity
Kappa - low affinity
Why is morphine fast-acting?
Crosses blood-brain barrier quickly
What is morphine’s major metabolite, and what process is used to create it?
Morphine-6-glucuronide
Glucuronidation
What is heroin metabolised to, and how?
- Diacetylmorphine via acetylation of morphine
- 6-monoacetylmorphine (6-MAM)
Heroin is completely illegal. True or false? Give an example
False
Legally prescribed as diamorphine
What is the white-crystalline form of heroin?
Diacetylmorphine hydrochloride
What is 6-MAM’s affinity to each opioid receptor?
High affinity at mu
What are the effects of 6-MAM?
Similar and greater to/than morphine
Is 6-MAM addicting? Explain
Yes
Has extremely rapid affect
Why is 6-MAM lipid-soluble? Explain the benefit of this
Has acetyl groups
Allows the drug to pass through membranes with ease
What is the effect of the mu receptor?
Inhibits GABA release which is responsible for dopamine inhibition, results in dopamine high
What is the body’s response to opioid use?
Reduce natural opioid peptides (endorphins) creating dependence
What are the withdrawal symptoms of opioids?
Anxiety
Depression
Cramps
Vomiting
Diarrhoea
Severe sense of pain not caused by anything
What is the effect of codeine? How is this useful in medicine?
Causes respiratory depression, and depressed cough
Useful in cough medicine
What is the affinity of codeine to each opioid receptor?
Low affinity to all
Is codeine analgesic?
No, it is only analgesic when it is converted to morphine
How is codeine converted to morphine?
When orally administrated, 10% is O-demethylated and then converted to morphine in the liver by P450 enzymes
Why is codeine a drug of abuse? Give some effects
Mixed with alcohol to create lean
- Euphoria
- Dissociative feeling from parts of body
What is methadone’s medicinal use?
Treats heroin addiction
Reduces physical dependence
What is the t1/2 of methadone?
24-48 hours
What is the effect of pethidine use?
Analgesic effects at kappa receptor
Cause dependence -> drug abuse
Less likely to cause addiction
What receptor does fentanyl work at?
mu, specifically u
How much stronger is fentanyl compared to morphine?
1000x
How is fentanyl used medicinally?
Patches
Flavoured lollipop - fentanyl citrate
What is the use of opioid antagonists?
Treat opioid addiction
Name the two opioid antagonists
Naloxane and naltrexone
Describe what naloxane does
- acts on mu receptor, competitive inhibition
- intravenous administration
- produces opioid withdrawal symptoms
Describe what naltrexone does
- alcohol addiction treatment
- mechanism unknown - just works
- more potent than naloxane
