Introduction Flashcards
psychoactive drug use in Canada has….
decreased but alcohol use has increased
opiate toxicity deaths in Canada has….
increased over the years. might have a covid related impact
one of the first mentions of substances is in the
bible (noah)
what were used for recreation and pain relief in the 18th and 19th century?
opium and laudanum (opium in alcohol). there were 2 opium wars (biritsh and european won)
2 important advances that allowed widespread use of morphine and heroin?
mid 19th century = chemical and technical advancements created more powerful substances produced cheaply and more available
heroin developed from opium as a less addictive form of morphine - inhibits coughing reflex
what was used to treat fatigue and other issues?
cocaine. very efficient as a local anaesthetic.
psychostimulant drugs were used in armies to…
stimulate soldiers and reduce anxiety. this is the reason why the soldiers acted like nothing can stop them since they were pumped with methamphetamine.
Pure Food and Drug Act (1906)
most impact on reducing drug addiction in US. all medicine bottles had to have all ingredients clearly labelled. reduced amount of substances available over the counter and the number of dependent people
Harrison Act (1914)
addressed mostly opioids and cocaine, it was a tax. even though it was really cheap to produce there was a tax put on it so it wasn’t cheap to produce due to the tax
Would get charged not for having drugs on you but for tax evasion
18th Constitutional Amendment ( Alcohol prohibition)
amendment banned the dispensing of anything with more than 0.55 alcohol. there was an immediate drop but when the amendment was removed, the numbers rose again. organized crime became more organized to smuggle alcohol better. even before the amendment, there was a reduction in the consumption of alcohol.
Marijuana Tax Act (1937)
In canada, possession of cannabis became illegal in 1961. cannabis that wasnt for medicinal use was prohibited. the new federal bureau of narcotics found no evidence of marijuana being a dangerous drug so this act was declared non-constitutional in 1969
Opium Act of 1908
first act against drugs that prohibited selling but not using.
tolerance
- 2 definitions: reduced effect of the same dose(lower impact over repeated exposure) or increase the dose to get the same effect
- higher dose and higher frequency causes tolerance to develop faster
- LSD has rapid tolerance and barbiturates have very little tolerance
- tolerance develops to particular effects of the substance (pain reducing effects of morphine, nausea and vomiting effects of opiates)
- inhibition of breathing centre develops tolerance = reason for opiate overdose
- constipation does not develop tolerance
- tolerance is almost reversible for almost every drug
mechanisms of tolerance
3 mechanisms
Metabolic (dispositional), physiological (pharmacodynamic), behavioural (conditioned)
Metabolic (dispositional) tolerance
related to half life. drugs are removed from circulation by enzymes (ex: p450). The more enzymes there are, the quicker it will be removed. With repeated exposures, more of the enzyme is being produced meaning the drug will be cleared quicker. That’s why it seems when you take more of the drug there is less of an effect since there is less drug reaching the target area
physiological (pharmacodynamic) tolerance
changes in the target area. interacts with special proteins called receptors - involves cellular and molecular changes. the body learns how to deal with this repeated exposure by changing the targets. there is a change receptors - a reduction of density at the surface.
behavioural (conditioned) tolerance
learning mechanism, conditioning effect. classical conditioning, operant conditioning leading to tolerance. sensitive to context - increases the risk for overdose if taking drug in a new environment
sensitization
increases the impact of the drug. repeated exposure to the substance shows an increase of the effect of the substance. easiest to show locomotor sensitization. if the dose is too large, get the opposite effect which is tolerance. once sensitization develops, not easy to reverse (stays for a long time). there is cross sensitization between drugs like cocaine and amphetamine and stress.
sensitization mechanisms
2 mechanisms = physiological adaptation and conditioned effects
physiological adaptation (cellular and molecular)
the brain adapts - it changes. in extreme cases, 1 exposure is enough to cause long term changes at the molecular and cellular level
conditioned effects
impact of the environment. exposing subject to psychostimulant in home environment is difficult to show sensitization. sensitization procedure works bests in a novel environment.
experiment showing sensitization
the effects of repeated administration of amphetamine on locomotor activity in rats was tested to show sensitization. exposing amphetamine through IV (remove any other cues - animals dont know theyre getting drug). had a saline control group. there was 7 days of repeated exposure followed by 7 untreated days. amphetamine challenge showed that the group that got amphetamine in novel environment had a higher impact when re-exposed to amphetamine showing sensitization in the novel group.
withdrawal symptoms
physiological and psychological changes that occur when drug use is stopped or dose decreased. intensity is different depending on the drug. heroin and alcohol has severe withdrawal symptoms. withdrawal from alcohol can kill you. withdrawal from marijuana has mild to no symptoms.
DSM opioid use disorder criteria
need only 2 of the presented symptoms within 12 months. many combinations possible. both tolerance and withdrawal are not sufficient for substance use disorder. impaired control, social impairment, risky use of drug, pharmacological criteria.
