cannabis pharmacology Flashcards
uses for medial marijuana
control nausea/vomiting, analgesic
reduce intraocular pressure, anticonvulsant, appetite stimulant, withdrawal from depressants and opioids
what are cannabinoid drugs
cannabidol– seizures
dronabinol, nabilone– nausea/vomiting in cancer
nabiximols- neuropathic pain, MS spasticity
THC vs CBD
THC: psychoactive, partial agonist, targets CB1/CB2
CBD: non-psychotropic, low affinity for CB1/CB2
___ decreases THC clearance by CYP inhibition
CBD
solubility of THC
low solubility
high lipophilicity
overdose from THC?
no documented fatalities
THC/CBD precursor
CBG
onset/duration smoked versus PO
smoked: onset 1-2 minutes, duration 4 hours
PO: onset 30 minutes, duration 6 hours
positive/negative effects
positive: euphoria, relaxation, laughing, appreciation for music
negative: anxiety, fear, paranoia, panic, hallucinations (rare)
acute effects
dry mouth, stim appetite, antiemetic at low dose, n/v at high dose, inc HR, orthostatic hypotension, red eyes (dilate blood vessels)
impairs attention, short term memory, some complex cognitive processes, motor abilities
long term effects
impaired cognition: attention, memory, problem solving, mental flexibility
altered brain function on neuroimaging: prefrontal cortex, cerebellum, hippocampus
symptoms of cannabis withdrawal
craving cannabis
sleep difficulties, irritability, anxiety
marijuana is ____ soluble
fat soluble
ADME
inhalation: absorption directly through the lungs, onset in a few minutes, peak concentrations 30-60 minutes, drug effects for 2-4 hours.
lipid soluble: deposits in tissues of fatty organs such as brain, lungs, kidneys, liver (even when blood levels of THC are zero, levels can be substantial in other organs
oral ingestion is_____ compared to inhaled
slower, inefficient: onset can take up to an hour, drug effects can be experienced for longer periods of time (4-6 hours), the dose needed to create a comparable high is 3x greater
THC is capable of crossing ____
placenta and reaching fetus
general THC concentration following ingestion
THC absorbed through lungs causes rapidly rising levels of THC in blood plasma
after peak levels reached, plasma THC levels begin to decline
metabolism by liver
accumulation of drug in fat stores
THC metabolism
metabolized twice by liver enzymes CYP2C9
when does tolerance occur
when high doses are used over extended periods of time
why can you overdose on opioids, cocaine but not marijuana
receptors for anandamide are found in several regions of the brain, but not much in the brainstem (as compared to receptors for opioids and cocaine)
mechanism
main target: presynaptic endocannabinoid CB1 receptor: presynaptic inhibition of GABA neurons, disinhibition of dopamine neurons, increase dopamine release
describe the parts of the endocannabinoid system
receptors: cannabinoid receptor 1 & 2 (CB1, CB2)
endocannabinoids: anandamide, 2-AG
enzymes: fatty acid amide hydrolase (FAAH)
where is CB1 expressed
central nervous system
where is CB2 expressed
peripheral immune cells
the psychoactive & reinforcing effects come from ___
CB1
