Symposium 3 - Addictions Flashcards
What mechanisms are involved with substance misuse?
Tolerance (dependence) Reward centre (cravings)
What is tolerance?
Reduced responsiveness to a drug caused by previous administration
Form of homeostasis
What are the mechanisms for dispositional drug tolerance?
Decreased absorption
Increased metabolism to INACTIVE metabolites
Decreased metabolism to ACTIVE metabolites
Increased excretion
What are the mechanisms for pharmacodynamic drug tolerance?
Down-regulation of drug receptors
Reduced signalling of drug receptors
What are the main mechanisms of tolerance?
Dispositional tolerance - less drug reaches active site
Pharmacodynamic tolerance - drug has less action at site
What is the mechanism of withdrawal?
Reverse of the acute effect of a drug
What is physical dependence?
Avoidance of withdrawal effects of a drug
What is the reward pathway?
Neurones project from ventral tegmental area to nucleus accumbens & prefrontal cortex
VTA neurones release dopamine
Leads to pleasure
What is the function of the reward pathway?
Reward the individual for eating, drinking and sex to encourage healthy behaviours
How does heroin effect the reward pathway?
Increases firing of dopaminergic neurones
How does amphetamine effect the reward pathway?
Increase dopamine release
How does cocaine effect the reward pathway?
Inhibits dopamine reuptake
How long do the modalities of cocaine take to onset?
Smoking - immediate
Injecting - 15-30s
Insufflating - 3-5mins
What are the recreational effects of cocaine?
Stimulant and Euphoriant Alertness and energy Confidence Impaired judgement Lessens appetite & desire for sleep
What are the harmful effects of cocaine?
Damage to nose/airways Convulsions Arrhythmias and MI HTN Toxic confusion Paranoid psychosis
What are the withdrawal effects of cocaine?
Depression Irritability Craving Agitation Hyperphagia Hypersomnia
What are the harmful effects of amphetamines?
Toxic confusion
Convulsions
Death
Amphetamine psychosis
What are the recreational effects of heroin use?
Analgesia
Drowsiness
Euphoria
Decreased sympathetic outflow
What are the harmful effects of heroin use?
Respiratory depression Cough reflex suppression N+V Hypothermia Pupillary constriction Constipation
What are the overdose effects of heroin use?
Respiratory arrest with pulse Unreactive pupils Bradycardia Hypotension Coma
What are the side effects of opiates?
First time - N+V, headache Medium term: - phlebitis - anorexia - constipation Long term: - tolerance, withdrawal
What are the withdrawal effects of heroin use?
Craving Insomnia Yawning Muscle pain Increased parasympathetic secretions Dilated pupil Piloerection
How is heroin addiction managed?
Methadone maintenance
What are the pros/cons of methadone maintenance?
Decriminalises drug use
Normalises lifestyle
Reduces IV misuse
Leaks to black market
What are the recreational effects of MDMA?
Relaxed euphoric state without hallucinations
Sociability
2-4hrs duration
What are the side effects of MDMA?
Nausea Dry mouth HTN Hyperthermia Dehydration risk Anxiety and panic Psychosis
How has THC content of cannabis changed over time?
1% in 70s
17% now
What are the psychological effects of cannabis?
Relaxing/stimulating
Euphoriant
Increased sociability, appetite
Synaesthesia
What are the high dose effects of cannabis?
Anxiety Panic Persecutory ideations Hallucinations Exacerbation of mental illness
What are the legitimate indications for anabolic steroids?
Hypogonadism
Muscular dystrophy
Anaemias
Muscle wasting in AIDS
Marked muscle mass increase is seen where in anabolic steroids use?
Pectoralis
Deltoids
Trapezius
Biceps
What are the general side effects of anabolic steroids?
Acne Stretch marks Baldness Cholesterol Hypertension Growth deficits Liver disease Roid rage, mania Depression and suicidality in withdrawal
What are the male side effects of anabolic steroids?
Hypogonadism
Gynocomastia
What are the female side effects of anabolic steroids?
Virilisation Hirsutism Deep voice Clitoral enlargement Menstrual abnormalities Hair thinning
How can D2 antagonists be used in addiction?
D2 receptors are blocked which stops addiction, but causes lethargy and low mood
Amphetamine psychosis may present similar to what?
Schizophrenia
Heavy chronic amphetamine use can lead to what?
Amphetamine psychosis
How does the route of heroin use change over the course of addiction?
Starts with smoking (often) which is more expensive, leads to injection over time due to losing money
