Drugs of Abuse Flashcards
What is the fastest route of drugs going to the brain? Why?
Inhalation because pulmonary circuit is very short and IV must do the systematic circuit before entering the brain
What are different classifications of drugs?
- narcotics
- depressants
- stimulants
- miscellaneous (have effects from multiple classes)
What is the order of onset of euphoria of a drug according to their administration method?
- inhalation
- IV
- intranasal
- oral
What is the difference between cannabis, hashish/resin and hash oil?
Cannabis is the plant, hashish/resin is the trichomes, hash oil is the solvent extract
What is the most potent cannabinoid?
Delta9 THC
What are the positive aspects of smoking weed from?
Cannabidiol
What is the difference between doses of THC between now and the 60/70s?
In the 60/70s it was ~10mg THC but now it’s 150-300mg
Cannabidiol potency would also have increased proportionally
What are routes of administration of cannabis? How much THC is delivered by this route?
Oral - 5-15% THC
Inhalation - 25% THC
Why and how does cannabis accumulate in the body?
It is very lipid soluble so builds up as fatty acid conjugates
How is cannabis metabolised in the body?
Liver converts THC to 11 OH THC which is more potent, then GIT excretes 65% of it - much of THC undergoes enterohepatic recycling due to lipid solubility and urine excretes 25%
What is the correlation between plasma concentration of cannabis and the degree of intoxication and why?
THC is more concentrated in brain matter than in blood as the blood is very lipid soluble, leading to a poor correlation
What receptors in the brain respond to cannabis and where in the brain are they
CB1R in:
Hippocampus, cerebellum, cortex, and basal ganglia
What receptors in the peripheral respond to cannabis and where are htey
CB2R in
Immune cells
What causes the euphoric affects of cannabis?
Stimulation of the Gi CB1 receptor inhibits the release of DABA - disinhibition leading to an increase in the release of dopamine by inhibiting DA release
What is CBR?
An inhibitory gpCr linked to Adenylate Cyclase
What is the body’s natural version of THC
endogenous anadamide
What is the anterior cingulate cortex in the brain involved in?
Performance monitoring with behavioural adjustment eg driving a car whilst talking to a friend then it starts raining so you stop talking to focus on the road
What is cannabis’ affect on the anterior cingulate cortex?
hypoactivity which can lead to psychosis and schizophrenia
How does cannabis affect food intake?
- presynaptic inhibition of GABA leading to an increase in MCH (melanin concentrating hormone) neuronal activity
- increase orexin production
which increases hunger
What is cannabis’ affect on the immune system and how does it do this?
Immunosuppressant bu agonising CB2Rs on:
mast cells, macrophages, b cells, t cells and natural killer cells
What are central affects of cannabis?
Psychosis, schizoprenia, food intake - lateral hypothalamus, memory loss, decreased psychomotor performance