Addiction Symposium Flashcards
What are the 2 distinct mechanisms implicated in why we use drugs?
- Tolerance (the basis of physical dependence)
- Reward centre (the basis of psychological craving)
Tolerance
reduced responsiveness to a drug caused by previous administration
What is tolerance an example of?
homeostasis
What does tolerance develop in response to?
many types of drug
- opioids, ethanol, barbiturates, benzodiazepines
What are the 2 mechanisms of tolerance?
dispositional tolerance: less drug reaches the active site
pharmacodynamic tolerance: drug has less action at the active site
What is the result of dispositional tolerance?
- decreased rate of absorption
- increased rate of metabolism to inactive metabolites
- decreased rate of metabolism to active metabolites
- increased rate of excretion
What is the result of pharmacodynamics tolerance?
- fewer drug receptors
- less efficient drug receptors
What may the development of tolerance lead to?
Withdrawal symptoms
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What is the withdrawal phenomena?
the reverse of the acute effect of the drug
What are the acute and withdrawal effect of opioids?
Acute
-Constipation
Withdrawal effect
-Diarrhoea
What are the acute and withdrawal effect of barbiturates?
Acute
-Anticonvulsant
Withdrawal effect
-Convulsions
What are the acute and withdrawal effect of cocaine?
Acute
-Elevated mood
Withdrawal effect
-Depressed mood
Describe the reward pathway.
- neurones project from the ventral tegmental area to the nucleus accumbens & prefrontal cortex
- when VTA neurones are stimulated they release dopamine is released
- this causes a sensation of pleasure/reward
Why has the reward pathway evolved?
- reward pathway activated by eating, drinking and sex
- encourages ‘healthy’ behaviours that lead to propagation of your genes
Give examples of some drugs of abuse that tap into the reward pathway and increase dopamine levels
- heroin (increases firing rate of dopaminergic neurones)
- amphetamine (increases dopamine release)
- cocaine (inhibits dopamine uptake)
- alcohol
Give 2 examples of stimulants.
- Cocaine
- Amphetamine
What has cocaine be used for in the past?
ENT surgery
What is the most potent natural stimulant?
Cocaine
How can cocaine be taken?
cocaine (powder)
crack cocaine is smoked (cocaine + base + purified)
How does the means of consumption affect the effects of cocaine?
depends on dose and rate of entry to the brain
- smoking: almost immediate
- injecting 15 to 30 secs
- snorting: 3 to 5 mins
- the effects of crack smoking are very intense but quickly over ( 15 mins)
What are the effects of cocaine?
- Stimulant and euphoriant
- Increased alertness and energy
- Increased confidence and impaired judgement
- Lessens appetite and desire for sleep
- Damage to nose and airways
- Convulsions with resp failure
- Cardiac arrhythmias and MI
- Hypertension and CVA
- Toxic confusion
- Paranoid psychosis
What are the withdrawal effects of cocaine?
- Depression
- Irritability
- Agitation
- Craving
- Hyperphagia
- Hypersomnia
What is the general amphetamine used?
Amphetamine sulphate
How is amphetamine consumed?
- sniffed
- swallowed
- injected
What are the effects of amphetamine?
effects similar to cocaine but longer lasting
toxic confusion occasionally with convulsions and death
Give examples of opiates.
- Opium
- Morphine
- Heroin (diamorphine)
- Methadone
- Codeine and dihydrocodeine
What is heroin available as?
- Diamorphine
- Diamorphine hydrochloride
How does purity of heroin vary?
Purity varies from 1%- 98% with average of 35% in US
What are other names for heroin?
- H
- Gear
- Smack
- Brown
How is heroin consumed?
- snorted
- smoked (chasing the dragon) (safest method)
- injected (most dangerous method)
What are the effects of heroin?
- analgesia
- euphoria
- pin point pupils
- itching/sweating
- constipation
- decreased libido/menstrual irregularities
- reduced cough reflex
What are the effects of heroin overdose?
- respiratory depression
- snoring
- bradycardia
- hypotension
- death
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What are the side effects of opiates?
first term: nausea/vomiting, headache
medium term: phlebitis, anorexia, constipation
longer term: tolerance, withdrawal, social/health problems
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What are the signs and symptoms of opiate withdrawal syndrome?
- craving
- insomnia
- yawning
- muscle pain and cramps
- increased salivary, nasal and lacrimal secretions
- dilated pupils
- piloerection
What are the consequences of methadone maintenance?
- decriminalises drug use
- allows normalisation of lifestyle
- reduces iv misuse
- leakage on to the illicit market
What is ecstasy?
- 3,4-methylenedioxymethamphetamine
- Half of all ecstasy contain no MDMA
- Causes a relaxed euphoric state without hallucinations
What are the effects of ecstasy?
- euphoria
- calmness
- increased sociability
- inability to distinguish between what is and isn’t desirable
What are the side effects of ecstasy?
- nausea and dry mouth
- increased blood pressure and temperature
- drug induced psychosis
- liver and brain cell damage
What is the most commonly used illicit drug?
Cannabis
What is the psychoactive agent in cannabis?
Tetrahydrocannabinol
What form of cannabis has a high THC content?
Skunk (sensimilla)
How can cannabis be presented?
- Marijuana
- Hashish (cannabis resin)
- Hash oil (produced by extracting cannabinoids from plant material with a solvent)
How is cannabis consumed?
- Eaten
- Usually smoked
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What are the psychological effects of cannabis in low doses?
- relaxing or stimulating
- euphoriant
- increases sociability and hilarity
- increases appetite
- changes in time perception
- synaesthesia
What are the psychological effects of cannabis in higher doses?
- anxiety
- panic
- persecutory ideation
- hallucinatory activity
What are the ill effects of cannabis?
- respiratory problems
- toxic confusion
- exacerbation of major mental illness
- cannabis psychosis
Give examples of novel psychoactive substances.
- NPS
- Legal highs
What are anabolic steroids?
family of drugs comprising testosterone and many synthetic analogues
What are anabolic steroids legitamely prescribed for?
- Hypogonadism
- Muscular dystrophy
- Various anaemias
- Wasting in AIDs
Why are anabolic steroids used cosmetically?
- increase muscle mass
- reduce body fat
Muscle hypertrophy from steroid use is particularly marked…
In the upper body in the pectoralis, deltoid, trapezius and bicpes
What are the side effects of anabolic steroids?
- skin: acne, stretch marks, baldness
- feminisation in males with hypogonadism and gynaecomastia (occasioning use of anti-oestrogens)
- virilisation in women including hirsutism, deep voice, clitoral enlargement, menstrual irregularities , hair thinning
- cardiovascular: increased cholesterol and hypertension
- growth deficits due to premature closure of epiphyses
- liver disease: cholestatic jaundice and liver tumours
What are the psychological side effects of anabolic steroids?
- irritability and anger (‘roid rage’)
- hypomania and mania
- depression and suicidality on withdrawal
How is the psychological component of addiction (craving) produced?
Drugs can tap into the reward centre to increase dopamine levels
How can heroin be presented?
- Powder
- Tar like substance
