Addiction Flashcards
Define Tolerance
Reduced responsiveness to a drug caused by previous administration.
What are the two mechanisms of tolerance?
- Dispositional
- Less drug reaches the active site
- Pharmacodynamic (aka tissue or functional tolerance)
- Site of action is less affected by the drug
Describe the dispositional mechanism of tolerance.
- less drug reaches the active site, eg
- decreased rate of absorption
- increased rate of metabolism to inactive metabolites
- decreased rate of metabolism to active metabolites
- increased rate of excretion
Describe the pharmacodynamic mechanism of tolerance.
- site of action is less affected by the drug, eg
- down-regulation or internalisation of drug receptors
- reduced signalling down stream of drug receptors
- some other compensatory mechanism
What is the withdrawal phenomena?
The withdrawal effect of the drug is usually the opposite of the acute effect.
Examples of stimulants.
- Cocaine
- Amphetamine
Cocaine desireable effects
- Stimulant and euphoriant
- Increased alertness and energy
- Increased confidence and impaired judegment
- Lessens appetite and desire for sleep
Cocaine damaging effects
- Damage to nose and airways
- Convulsions with respiraotry failure
- Cardiac arrhythmias and MI
- Hypertension and CVA
- Toxic confusion
- Paranoid psychosis
Cocaine withdrawal effects
- Depression
- Irritability
- Agitation
- Craving
- Hyperphagia
- Hypersomnia
Amphetamine effect
Similar to cocaine but longer lasting
Examples of opiates
- Opium
- Morphine
- Heroin
- Methadone
- Codeine and dihydrocodeine
Heroin is taken by:
- Snorting
- Smoking
- Injection
Smoking is the safest and injecting is the most dangerous method of use.
Effects of heroin:
- Analgesia
- Drowsiness and sleep
- Mood change (euphoria, intense pleasure)
- Respiratory depression
- Cough reflex depression
- Sensitisationof the labyrinth with nausea and vomiting
- Decreased sympathetic outflow (bradycardia and hypotension)
- Lowering of body temperature
- Pupillary constriction
- Constipation
Effects of heroin overdose
- Respiratory arrest with a pulse
- Pinpoint pupils unreactive to light
- Snoring giving way to shallow respiration
- (<8 breaths/min)
- Bradycardia and hypotension
- Varying degree of reduced conciousness/coma
Side effects of opiates
- First time
- nausea/vomiting
- headache
- Medium term -
- phlebitis
- anorexia
- constipation
- Longer term
- tolerance
- withdrawal
- social and health problems
Opiate withdrawal syndrome
- Craving
- Insomnia
- Yawning
- Muscle pain and cramps
- Increased salviary, nasal and lacrimal secretions
- Dilated pupils
- Piloerection
Benefits of methadone maintainance
- Decriminalises drug use
- Allows normalisation of lifestyle
- Reduces IV misuse
Ecstasy (MDMA) - Effects
- Euphria followed by a feeling of calm
- Increased sociability
- Inability to distingush between what is and isn’t desireable
- Effects after 20 minutes lasting 2-4 hours
Ecstasy (MDMA) - side effects
- Nausea and dry mouth
- Increased blood pressure and temperature
- Large doses can cause anxiety and panic
- Drug induced psychosis
What is the psychoactive agent in cannabis?
Tetrahydrocannabinol (THC)
Psychological effects of cannabis
- Relaxing or stimulating
- Euphoriant
- Increases sociability and hilarity
- Increases appetite
- Changes in time perception
- Synaesthesia
Psychological effects of higher doses of cannabis.
- Anxiety
- Panic
- Persecutory ideation
- Hallucinatory activity
Cannabis - side effects
- Respiratory problems as with tobaco
- Toxic confusion
- Exacerbation of major mental illness
Physical side effects of steroids
- Skin - acne, stretch marks, baldness
- Feminisation in males with hypogonadism and gynaecomastia
- 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, liver tumours
Pschological side effects of steroids
- Irritability and anger - roid rage
- Hypomania and mania
- Depression and suicidality on withdrawal
