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
What is cocaine
A stimulant
Blocks uptake of NA, dopamine and serotonin
How is it taken
Injected
Snorted
Smoked
+ve effects
Stimulant Euphoria - dopamine Alert Energy Confidence Decreased appetite Decreased need for sleep
-ve effects
Vasoconstrictor Raised BP Resp failure Cardiac arrhythmia - QT prolonged MI due to coronary vasospasm Aortic dissection Ischaemic colitis Hyperthermia Metabolic acidosis Rhabdomyolysis Tachy or Brady Paranoid psychosis Financial / social
What does cocaine do to pupils and what are withdrawal affects
Dilate
Depression
Irritable
Craving
Desire for food and sleep
How do you Rx toxicity
Benzo = 1st line
Add GTN if chest pain then PCI if MI develops
Add sodium nitrprusside if high BP
Amphetamine
Similar to cocaine but last longer
Toxic confusion, convulsions and death
Examples of opiates
Opium Morphine Heroin Methadone Codeine
How can heroin be taken
Injected
Snorted
Smoked
What does heroin do
Analgesia Drowsy Resp depression Cough reflex depression Causes 'a rush' N+V Decreased sympathetic - Brady / hypotension Decreased body temp Constipation Viral infection - hep B / C / HIV by sharing needles Bacterial infection - IE / SA / necrotising fascitis/ sepsis VTE Social issues
What is characteristic sign of overdose
Respiratory arrest with a pulse
What are other signs
Pinpoint pupils
Resp <8
Braydcardia
Hypotension
How do you Rx overdose
Nalaxone
What are symptoms of withdrawal
Craving Insomina Muscle pain Dilated pupils Increased gland secretion
What is methadone
Long term opiate to decrease craving Can also use bupronephrine Decriminaise drug use Reduce IV Compliance monitored using urinalysis
What is ecstasy
MDMA
What does ecstasy cause
Same as cocaine / LSD Dilated pupils Tachycardia High BP Hyperthermia Hyponatraemia Dehydration Liver and brain cell damage
Rx = supportive or dantrolene if hyperthermia
What is psychoactive agent in cannabis
THC
What are affects of cannabis
Relax Increased sociable Increased appetite Change in time Merging of senses - synaesthesi
What does high THC cause
Anxiety Persecutory ideation Hallucination Rest issue Exacerbate mental illness
What are novel psychoactive substances
Legal high
When are anabolic (androgenic) steroids prescribed
Hypogonadism
Muscular dystrophy
AIDs wasting
What are SE
Muscle hypertrophy Acne Stretch marks Feminisation Hypogonadism Gynaecomastia Virilisation Growth Cholesterol BP Liver Mania
What is Virilisation
Hirsutism Deep voice Clit enlargement Menstrual irregularity Thin hair
