Substance Misuse Flashcards
What are the mechanisms of substance misuse and what are they the basis of
Tolerance - basis of dependence
Reward - basis of craving
What is tolerance
Reduced responsiveness to drug caused by previous administration
What drugs can you become tolerant too
Opioids
Ethanol
Barbiturates
Benzodiazepine
What is dispositional tolerance
Less drug reaches active site
Decreased absorption
Increased metabolism
Increased excretion
What is pharmacodynamic tolerance
Down regulation so less efficient or fewer receptors
What does tolerance lead too
Withdrawal symptoms
Drug tries to return body to homeostasis when drug administered
When drug is stopped body’s response to combatting drug causes withdrawal symptoms
Often opposite to drug effect as body trying to do opposite
Why does tolerance cause dependance
Body becomes dependent to avoid withdraw symptoms
What is the reward pathway - where does it project
Neurones project from ventral segmental area to nucleus accumbens and cortex
What happens when VTA stimulated
Dopamine is released
Causes sense of pleasure / reward
What do drugs do
Heroin / cocaine / amphetamine
Can stimulate this pathway
Causing craving of reward feeling
What will D2 antagonist do
Treat craving as blocks reward pathway but not dependence
Why are some people more prone to addiction
Dopamine receptors can vary
What do you do for drug addiction
Hx 21 day referral to services BBV and urine drug screen Follow up Possible methadone
Who is high risk and may get faster referral
Neck injector
Pregnancy
Sex
Illness
What do you need before starting methadone
ECG
What can you say about methadone
Green liquid from pharmacy Dispensed daily Get heart tracing before Do you use any other drugs Any questions
