M3s3 Cannabis Flashcards
Cannabis
-aka THC
term refers to drug-containing forms of the hemp plant, Cannabis sativa, which an herbaceous annual
-60 chemical compounds found only in Cannabis sativa, and these compounds referred to as cannbinoids (CB)
-of these compounds I-trans-delta-9-tetrhydrocannabinol (THC), is the most potent psychoactive agent in cannabis and accounts for most, but not all of the psychoactive effects
History of cannabis
2700 BCE - 1800 CE -> cannabis plants used for manufacturing rope. Used for mild intoxicating effects
1920s -> public concern raised in North America over the effects of cannabis on individual and society. Legislation was enacted to outlaw the use of cannabis, which considered a narcotic
1960s -> use decreased, this is purported to be driven by Cold War and changing political and cultural climate
1978 -> USA-sponsored project using herbicide paraquat was initiated in an attempt to destroy cannabis crops in Mexico. It failed. USA citizens were smoking cannabis products containing paraquat, which can produce lung toxicity
1997 -> Ontario court dismissed charges related to possession and cultivation of cannabis on the basis that the individual was using it to control epilepsy that was not controlled by conventional drug therapy. Canada changed the law to allow the cultivation of some varieties of cannabis that contain very small amounts of THC for the use in the manufacture of rope, clothing and other hemp products. Farmers must obtain special license to grow hemp
2005 -> health Canada supported trails on the medical use of cannabis
2012 -> recreational use of cannabis legalized in Washington
2018 -> in fall, recreational cannabis legal in Canada
Narcotic
A drug that affects behaviour or mood, consumed for non-medical reasons
Classification of cannabis
Pharmacological - cannabis classified as CNS depressant, euphoriant, hallucinogen (although the hallucinogenic properties only occur at high doses)
Legal - as of October 17, 2018, cannabis became legal in Canada
Administration of cannabis
-cannabis is a dried flowering plant that typically smoked or inhaled
-extracts containing concentrated amounts of cannabinoids, typically in oil, can be administered by vaping or through oil consumption
Mechanism of action of cannabis
-not fully understood
-well known that THC binds specifically to receptors located in the brain and spinal cord called type 1 cannabinoid receptors (CB)
-anandamide is an endogenous ligand for CB receptors involved in learning and memory processes
-The CB receptors, when activated by anandamide or THC, inhibits the release of excitatory neurotransmitters
-this explains the reduction in cognitive function and CNS depressant effects seen with THC
*refer to goodnotes
Cannabinoid receptors
-2 types, found in specific locations of body
CB1 RECEPTORS:
-large number in brain, more than any other receptor
-THC is not very effective agonist but as a large miner of receptors, it does produce a response
-> CB1 receptors in cerebral cortex mediate the distortions of time, colour, sound and taste, decrease in cognitive function and concentration
-> CB1 receptors in hippocampus may account for changes in memory and learning
-> no CB1 receptors are present in brain stem, thus, cannabinoids do not depress respiration, explaining the relative non-lethality of drug
CB2 RECEPTORS:
-only found outside CNS
-do not appear to be involved in the psychoactive effects of THC, but may be involved in inflammation
-binding of THC to CB2 receptors on lymphocytes (white blood cells) is thought to be responsible for immunesuppressive properties of THC
*refer to goodnotes for images
ADME of THC
-THC primary component in cannabis causing psychoactive effects
1. Absorption
-commonly inhaled or ingested
Inhaled -> from smoke, rapid and the onset of action almost immediate, effects last 3-4 hours
Ingested -> when absorbed from oral administration, absorption occurs slowly and incomplete, onset of action delayed 30 to 60 minutes. Effect is less than that from smoking cannabis
- Distribution
-following inhalation, THC rapidly distributes throughout body, especially to tissue with high blood perfusion like lungs, heart, brain and lover
-THC also rapidly crosses the placenta
-these processes much slower following organ ingestion given the slow absorption of the route of administration
-THC highly lipid soluble and over time will be stored in adipose tissues - Metabolism
-slow
-metabolites can be measured in drug tests, so those communing cannabis chronically may test positive for the metabolites weeks after use has stopped - Excretion
-THC half-life approximately 30 hours
-elimination of THC from adipose tissue may take longer
Effects of short-term cannabis use
CNS
-relaxation and drowsiness
-feeling of well-being and euphoria
-impaired motor coordination
-increased appetite
As dose increases, person may experince pseudo-hallucinations (person knows its a hallucination), a running together of senses and impaired judgement and coordination. In some cases, a toxic psychotic reaction may occur
Cardiovascular system
-increased heart rate
-increased blood flow to the extremities
-postural hypotension (acute low blood pressure when standing or sitting up which can cause dizziness or fainting) may occur
GI tract
-increased appetite
-dryness of the mouth and throat
Other
-reduction of sex drive in males, as THC may reduce testosterone levels
-distraction of the ovarian cycle by THC in females
-hangover, similar to that with alcohol, when drug wears off
Effects of long-term cannabis use: psychological
-involve multiple body systems and range from easily reversible to serous
Psychological
Occasional low-dose: no harmful psychological effects
High doses: short-term memory loss, lack of concentration, loss of ability to abstract think. A motivational syndrome is characterized by these psychological problems, and loss of ambition and emotional flatness. Syndrome usually disappears upon cessation of drug use, suggesting that it represents chronic intoxication
Permanent effects: currently unknown. Some data suggests that structural changes do occur in the brain and may be associated with impairment of memory and learning
Effects of long term use of cannabis: cardiovascular
-usually reversible
-changes in blood pressure don’t appear to be serious but an increase in heart rate can be a potential problem for those with heart disease
Effects of long term cannabis use: respiratory
-bronchitis, asthma, sore throat, chronic irritation of and damage to membranes of respiratory tract (symptoms additive with simultaneous use of tobacco and cannabis)
-smoking cannabis can be damaging in long-term cause higher concentrations of tars and carcinogens present in cannabis smoke compacted to tobacco smoke
-cannabis typically inhaled deeply and head in lungs in order to maximize absorption of THC and other cannabinoids, plus enhances the amount of Tars and carcinogens absorbed
-the incidence of lung cancer and chronic obstructive pulmonary disease (COPD) are both increased with long-term use of smoked cannabis (most serious effects of long-term use)
Effects of long term use of cannabis: fertility
Males: lead to decrease sperm count
Females: can cause follicle stimulating hormone and luteinizing hormone to be reduced, and cycles can potentially occur without ovulation (ie. no release of an egg from ovary)
Pregnancy: THC freely crosses the placenta and can cause developmental delays leading to cognitive deficits, impulsiveness, and inattention and hyperactivity. Difficult to distinguish effects of THC from concurrent drug use, diet and poor prenatal care
Medical use of cannabis
-as more information is obtained on the functions of anandamide and its receptors, likely that drugs that bind to CB1 and CB2 receptors will be developed that are more effective and less toxic than THC
-challenge for pharmacological use is to separate the beneficial effects (ex. Analgesia (pain due to interruption of nervous system pathways between sense and organs and the brain) from the psychotropic effects
Authorized medical use of cannabis
-not health Canada approved therapeutic product yet healthcare practitioners may authorize the use of cannabis for the relief of a number of symptoms which have not responded to conventional medical treatments
Ex. Medical cannabis can be prescribed for the prevention of nausea and vomiting associated with anticancer drugs. That being said, synthetic THC derivatives are generally more selective than cannabis in treating nausea, so more effective and generally used instead of cannabis
Cannabis: potential for misuse and SUD
-misuse low to moderate as euphoria and reinforcement are less compared to some other drugs like cocaine
-inherent harmfulness of cannabis is low, especially with infrequent use
-greatest concern is automobile accidents, accidental exposure to children, and the lung effects associated with smoking
Tolerance:
Occurs to->
-the psychoactive properties of THC
-the effects on the cardiovascular system
-the impairment of performance and cognitive function
Withdrawal:
Upon termination of long-term high dose use, a mild withdrawal syndrome occurs, characterized by ->
-sleep disturbances
-irritability
-loss of appetite
-nervousness
-mild agitation
-upset stomach
-sweating
Addiction:
-develops as a persistent craving for the drug.
-risk of addiction is more evident in those who use cannabis to control psychological stress
