drugs and addiction lect 1 Flashcards
what is the most widely consumed drug
caffeine
what is the most harmful drug
alcohol
what is the most addictive drug in animal research
cocaine
what drug has caused the most deaths from overdose in uk
heroin
what is the most commonly used illegal drug
cannibis
what is addiction
a social construct
can only be measured in a clinical way by asking people or families about a patient’s symptoms
what is considered an addiction
when a drug has substantial LT neg effects on the life of an indiv
what is psychopharmacology
-study of drug induced changes in mood, cog and behaviour
what are drugs
prescribed medications, legal recreational substances or illegal recreational substances
what are the sources of drugs
natural or synthetic
how do drugs impact psychopharmacology
-act on receptors in neurons to induce physiological/ psychological changes
what is drug action
specific interaction between drugs and target sites or receptors
what is drug effect
action of drug on brain and body and the changes in psychological/ physiological function
examples of routes of administration
ingested
ocular
oral
nasal
inhalation
intravenous
what is the significance of diff routes of administration
-pharmacokinetics graph shows quickest administration method to hit brain and which method lasts the longest
-inhalation is the quickest, followed by injection (fast high)
-the slower the onset of the drug, the longer the effects will last as the build up is more gradual
-ingestion is the slowest method to peak but lasts the longest (slower high, less peak, slower to build up and then build down)
differing administration methods for cocaine
-duration of crack cocaine is much shorter than nasal/intravenous
-administration method important for duration/ intensity of effects
what may effect the choice of administration
-chemical characteristics of the drug (unprocessed drug e.g cannabis cannot be injected, only smoked and snorted etc
-personal preference e.g disliking injections
-speed which the drug acts
what does ROA mean
route of administration
ROA rural vs urban drug users in USA
Young et al 2010
-212 rural users vs 111 urban users
-prescription drug abuse
-urban users more likely to swallow drugs
-alternative routes used in rural populations
-linked to drug problem severity- higher in rural populations
effect of ROA of heroin on transition to regular use
Hines 2017
-395 heroin users in london
-looked at difference in speed of transition from first use to daily use according to ROA (injecting, snorting, smoking)
-those injecting were almost 5x more likely to progress to daily use within 1-3 weeks of first use than other methods
ROA and culture
-cultural norms and local legal policies can effect ROA
-changing views on cannabis and tobacco have affected ROAs
-changes in technology e.g vaping
cross cultural differences in cannabis
Hindocha 2016
-33,000 pp from 12 countries
-66% smoked cannabis with tobacco globally (method most used in europe but uncommon in USA)
-using non tobacco ROAs associated with desire and motivation to use less tobacco
-consistent with image of smoking in USA (implications for health and interventions)
differences in cannabis ROAs according to legalisation
Borodovsky (2016)
-2800 pp surveyed form USA
-in some states cannabis was legal for medical purposes (MML: medical marijuana laws), but illegal in others
-vaping and edibles higher in MML states
-the longer the duration of the MML, the higher the incidence of vaping and edibles, maybe bc of higher no. of dispensaries
how does absorption into bloodstream account for a difference in pharmacokinetics
-more barriers drug has to cross to reach brain, the slower the effect and drug likely to be degraded
–depends on degree to which drug is lipid soluble
–degree of ionisation: ionised forms less likely to cross cellular membrane than deionised forms
–size of molecule: smaller = faster
–diff in drug conc across mem, greater diff = faster crossing
absorption and ROAs
-intravenous = no absorption, straight to bloodstream and to site of drug action
-inhalation = chemical conc from lungs to blood is high so rapid, high lipid solubility and small particles
-mucus mem = several layers of cells to cross, aided by conc diff
-oral = very slow, often poor bc of degration by stomach and enzymes
distribution of drug through body
-journey through body
-stored in body tissue
-remains in blood stream
-metabolised
-needs to cross blood brain barrier (BBB)
-all properties that lead to rapid absorption can lead to more distribution and less drug getting to brain
what is the ultimate barrier
BBB
-highly defensive
-prevents damaging molecules entering brain
-drugs of abuse can cross BBB
heroin vs morphine
-both opiates
-heroin is derivative of morphine
-heroin more lipid soluble, crosses BBB more easily
-heroin can only last couple mins in body and is then converted to morphine when entering brain
oxycontin
-potent opioid with strong effects
-developed by purdue pharma 1996
-$48 million in 1996, $1.1 billion in revenue in 2000 due to oxycontin
-
what was the controversy surrounding oxycontin
-marketed as a safer, more acceptable drug
-no advantage over other potent opioids
-randomised double blind studies comparing oxycontin given every 12 hrs with immediate release
-oxycodone given 4x daily showed comparable efficacy and safety for use with chronic back pain (hale 1999)
-animal number of deaths rose after intro of oxycodone changed
-argument for oxycontin was it was less dangerous than heroin
-actually heroin use increased with rise of oxycontin (quadrupled heroin overdoses!!!)
why did heroin use go up with rise of oxycontin
-if people cannot get hold of oxycontin/codone they accessed heroin
-heroin is more street drug used
-oxycontin acts as a gateway drug to heroin and heroin is accessed in the streets
why is oxycontin abused
-slow release formula thought to lower abuse of this drug
-people changed ROA to eliminate the slow response: used chewing or crushing
-massive marketing in the US (private healthcare so diff to NHS in UK)
-misleading claims about addiction (less than 1%)
-high incentives for drug reps and doctors to sell oxycontin including a pay rise, rewards, bonuses etc
-in USA you can get coupons for oxycontin, oxycontin stuffed toys
-allow advertisement of psychoactive drugs on TV!!
USA vs europe health care systems
-private vs public
-in europe there is higher control on doctor shopping e.g changing surgery means your notes are passed on etc
-europe = less availability of opioids
-in usa they have online pharamcy for sales of unregulated medication
-doctor in europe will not reach for opiate until the last chance for the patient
-in europe there is tighter control over prescriptions
-in usa a high no of people use prescribed drugs
what are opiates
very effective pain relief that must be monitored
opioids in the UK
-330,000 high risk opioid users (0.5% of pop)
-over 2000 deaths from opioids in 2021 in england
what is an opiate
naturally derived drug from opium poppy e.g heroin, morphine, codeine
what is an opioid
any drug natural or synthetic which binds to endogenous opioid receptors
opioids in USA
-deaths from opioids = over 80,000
-in USA, 1 in 5000 use opioids, vs 1 in 30,000 across england and wales use opioids
drug elimination
-as soon as drug enters body, body tries to counter act it and get rid of it
-it is metabolised in liver and excreted by lungs, sweat, urine etc
-its the reverse of absorption
metabolism and excretion
-rate of metabolism and excretion is initially faster due to high drug conc on either side of kidney membrane but then rate slows
-alcohol is an exception, it is metabolised at a constant rate
(enzyme availability is limited)
what is drug half life
-length of effect/intoxication
-plasma conc of drug in blood is halved after one elimination half life
-in each succeeding half life, less drug is eliminated
-after 1 half life amount of drug in body is 50%
-2 half lives = 25% in body
-4 half lives = 6.25% in body etc etc
what does the drug half life reflect
-time for drug to be metabolised and excreted
-time interval to avoid withdrawal
-amount of drug ingested does not affect half life
e.g caffeine half life is 3-7hrs
-alcohol is the exception, it takes 1 hr to remove 1 unit of alcohol
e.g cannabis half life = 20 hrs (occasional use), 13 days for regular users
e.g heroin half life = 3-15 mins
