Addictions Flashcards
There are two sides to addiction:
Tolerance –> Physical Dependence
Reward Centres –> Psychological Craving
Define tolerance?
Reduced responsiveness to a drug due to past administration
What are the 2 main mechanisms of tolerance?
- Dispositional
- Pharmacodynamic
What’s dispositional tolerance?
LEss drug reaching the active site due to changes in absorption, metabolism, excretion etc
What’s Pharmacodynamic tolerance?
Less effect of drug at the active site due to e.g. internalisation of receptors or less efficient receptors
How does tolerance cause dependence?
Physiological changes in response to the drug use causes you to depend on the drug to maintain your normal homeostasis
When the drug’s taken away you swing too hard the other way and get withdrawal
What do withdrawal symptoms look like?
Pretty much the opposite of whatever the drug’s effect is e.g. diarrhoea when you stop opiates
Describe how the brains “reward centres” work?
The Ventral Tegmental Area projects VTA neurons to the nucleus accumbens & prefrontal cortex releasing dopamine
How do drugs cause craving?
Basically they trigger some part of our reward pathways, usually increasing dopamine, triggering it’s release or decreasing it’s reuptake
What types of cocaine are there?
Cocaine hydrochloride is what you snort and inject
Cocaine freebase aka crack is what you smoke
What are the desired and undesired effects of cocaine?
Most potent natural stimulant - monoamine reuptake inhibitor
- Euphoria
- Confidence
- Energy
- Decreased appetite/sleep
- If mixed with alcohol, cocaethylene
Dangers include:
- Airway damage
- Convulsions
- Resp failure
- Arrhythmia
- MI
- HTN
- Toxic confusion & paranoid psychosis
What happens when you withdraw from cocaine
Think the opposite of the effects:
- Low mood & irritability
- Agitation
- Craving
- Hypersomnia
- Hyperphagia
How do you take amphetamine?
- Snort, swallow or inject
- Generally amphetamine sulphate
Effects of amphetamine?
Similar to cocaine but longer.
Risks:
- toxic confusions
- convulsions
- amphetamine psychosis
What are the forms of heroin?
Diamorphine or Diamorphine Chlorine
Comes in powder or tar and can be snorted, smoked or injected
Heroin gives an intense but transient pleasure rush, what are the side effects though?
Analgesia Emotional analgesia Nausea initially Euphoria Pin point pupils Itching/sweating Constipation Decreased libido/menstrual irregularities Reduced cough reflex
What do you get when you withdraw from heroin?
Craving Insomnia & yawning Muscle pain & cramps Increased secretion from nose, lacrima and saliva Dilated pupils Piloerection (hence cold turkey)
Why do we give people methadone?
Best case scenario is they remain opiate dependant but they are able to get their life together because its normalized, regulated, reduces IV misuse and so eliminates most of the social problems
What’s the big problem with buying mandy?
only 1/2 are mdma, the others are either nothing active, lsd, amphetamine or ket etc
What are the effects of MDMA?
Euphoria, increased sociability etc
Negative effects: Nausea Dry mouth HTN & high temp Dehydration Anxiety, panic & Psychosis
What are anabolic steroids prescribed for?
Hypogonadism
Muscular dystrophy
Anaemias
Wasting in aids
What are the side effects of steroid use?
- Acne, stretch marks and baldness
- Feminisation in males with hypogonadism and gynaecomastia (occasioning use of anti-oestrogens)
- Virilisation in women – Hirsutism, deep voice, clitoral enlargement, menstrual irregularities & hair thinning
- Cholesterol & HTN
- Growth deficits (closes epiphysis)
- Cholestatic jaundice & liver tumours
What are the best known opiates?
Opium Morphine Heroin (diamorphine) Methadone Codeine and dihydrocodeine
What is heroin?
Opioid agonist
- Acts via mu (principally)
- Acts principally via Mu, Delta and Kappa receptors
- Kappa and Delta – analgesia
- Mu – mood effects, analgesia and euphoria
