Drug Misuse Flashcards
What is tolerance?
Reduced responsiveness to a drug caused by previous administration
What drugs cause tolerance?
Opioids
ethanol
barbiturates
benzodiazepines
What are the two types of tolerance?
Dispositional tolerance
Pharmacodynamic tolerance
What is dispositional tolerance?
This concerns the part between the drug entering the body and reaching its receptor (active site).
Less of the drug actually gets to the active site.
What are some causes of dispositional tolerance?
Increased rate of excretion
Decreased rate of absorption
Increased metabolism - to inactive metabolites
Decreased metabolism - to active metabolites
What is pharmacodynamic tolerance?
When the same amount of drug reaches the receptor (active site) but it has less of an effect.
What are some mechanisms of pharmacodynamic tolerance?
Fever drug receptors
Same amount of drug receptors but less secondary messengers (that don’t produce as much cyclic AMP)
Down regulation of internalised drug receptors
What is the physiology of tolerance which leads to dependence?
Drug is given - produces a specific response
Body counteracts this by producing an ‘adaptive’ response
Tolerance is achieved
Drug is removed which takes away its action on the body
Body is still producing the ‘adaptive’ response - might produce withdrawal symptoms
What withdrawal effect does a drug have?
Usually the opposite of the acute effect.
Write an example where an acute effect is constipation and write the withdrawal effect?
Person takes medication - gets constipation
Adaptive response is to make stools easier to pass
Homeostasis is maintained
Person comes off medication - body is still producing adaptive response.
since theres no constipation, easier passing stools results in diarrhoea.
What are the acute and withdrawal effects of opioids?
Acute - constipation
Withdrawal - diarrhoea
What is the acute and withdrawal effect of barbiturates?
Acute - anticonvulsant
Withdrawal - convulsion
What is the acute and withdrawal effect of barbiturates?
Acute - anticonvulsant
Withdrawal - convulsion
What is the acute and withdrawal effect of cocaine?
Acute - elevated mood
Withdrawal - Depressed mood
What is the main neurotransmitter involved in the reward pathways?
Dopamine
How does the reward pathway work?
Neurones in the VTA are stimulated and dopamine is released - this causes sensation of pleasure and reward.
How is the reward pathway usually activated?
Eating
Drinking
Sex
How is a psychological craving developed?
By activation of the reward centre/pathway.
How does heroin affect the reward pathway?
Increases firing of dopaminergic neurones
How does amphetamine affect the reward centre?
Increases dopamine release
How does cocaine affect the reward pathway?
Inhibits dopamine uptake.
Which gene has been found to be associated with an addictive personality?
A1 allele
What are the two main components of drug addiction?
Psychological - stimulation of the reward pathways
Physical - build up of tolerance
How long do the effects of cocaine last for?
15-90 minutes
how does cocaine work?
it blocks the reuptake of dopamine, norepinephrine and serotonin. (mostly dopamine).
What are the effects of cocaine?
euphoria vasoconstriction high blood pressure tachycardia hyperthermia confidence dilated pupils increased energy suppress appetite less desire for sleep anaesthetic effect
What are the withdrawal symptoms of cocaine?
depression anxiety cravings hunger sleeping vivid dreams (increase in REM sleep) fatigue reduced concentration
More serious: Suicical ideations nausea vomiting sensation of insects crawling over body
How long does cocaine take to be metabolised?
1hr by the liver.
How is a cocaine overdose treated?
Sedative + keep cool
What is a mixture of cocaine and alcohol called?
Cocaethylene - has a much longer half life
How long does cocaine take to work via the different routes of entry?
Injection - almost instantly
Inhalation - 3-5 mins
Smoking - almost immediately
How long do the effects of crack smoking last for?
Very intense - only last 15 mins.
What complications can cocaine cause?
Nasal and airway damage Hypertension Toxic confusion Paranoid psychosis Colvunsions with respiratory failure Cardiac arrhythmia MI
Which organ can cocaine affect the most?
Heart - very cardiotoxic.
What are some types of opiates?
Heroin Methadone Morphine Codeine Dihydrocodeine
How do opioids work?
They bind to opioid receptors - this blocks pain pathways and cause euphoria.
What are the 3 main types of opioid receptors?
Mu (main) - mood, analgesia and euphoria
Kappa - analgesia
Delta - analgesia
How long is the half life of heroin?
30 minutes
What are the effects of heroin?
Analgesia Emotional analgesia Initially nausea Euphoria Pin point pupils itching sweating constipation reduced libido menstrual irregularities reduced cough reflex Reduced heart rate Reduced blood pressure Wakefulness decreases
Which medication is given in an opioid overdose?
Naloxone - opiate antagonist - binds to the opioid receptors so that heroin can’t
How can heroin be ingested?
Snorting
Smoking
Injecting
What are the main effects of heroin in overdose?
Respiratory depression
Bradycardia
Hypotension
Death
What other substances taken with an opioid increase chances of death?
Other respiratory depressants:
Alcohol
Benzodiazepines
Which blood borne virus are IV heroin users at the biggest risk of?
Hepatitis C
What are the withdrawal symptoms of heroin?
Tachycardia Increased saliva, lacrimal and nasal secretions Yawning Insomnia Cravings Muscle pain Tremor Dilated pupils Goose Bumps (cold turkey) Diarrhoea Sneezing Sweating
How long does ecstasy take to have an effect and how long does it last for?
20 mins to căușe effect
last 2-4hrs
What are the main side effects of ecstasy?
nausea dry mouth hypertension hyperthermic dehydration anxiety and panic (in large doses) drug induced psychosis
How many people are legal cannabis users?
1 in 7
What are the two components which make up cannabis?
THC - tetrahydrocannabinol
CBD - Cannabidiol
What effects does THC from cannabis cause?
Psychedelic (trip) Hallucination everything is exaggerated funny jokes affects your mental state
What effect does the CBD part of cannabis do?
Anxiolytic - reduced anxiety
Antipsychotic
What ratio of ingredients is best in cannabis?
Cannabis with higher CBD and lower THC is safer.
what are the effects of high doses of cannabis?
Anxiety
Panic
Persecutory ideation
Hallucinatory activity
What does cannabis as a whole do at normal doses?
Relaxes or stimulates Causes euphoria Increases sociability and hilarity Increased appetite Changes in time perception Synaesthesia (blending of senses)
What are the negative effects of cannabis?
Respiratory problems
Toxic confusion
Exacerbation of major mental illness
Cannabis psychosis
What is an example of an injectable tanning agent?
Melotan
What are the side effects of anabolic steroids?
Acne stretch marks baldness feminisation in males - gynaecomastia Maleisation in females - deep voice, clitoral enlargement, menstrual irregularities, hair thinning, hirsutism Increased cholesterol and hypertension growth deficits liver disease irritability and anger hypomania mania depression or suicidality on withdrawal
