Drug Dependence and tolerance Flashcards Preview

Physiology & Science: Pharmacology > Drug Dependence and tolerance > Flashcards

Flashcards in Drug Dependence and tolerance Deck (18)
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1
Q

What is a drug?

A

Any chemical compound

2
Q

What is the ICD 10 criteria for diagnosis of substance dependence?

A
  • desire or sense of compulsion
  • difficulties in controlling substance use
  • a physiological withdrawal state
  • tolerance
  • prioritising use
  • persisting with subtance use despite consequences
3
Q

Name examples of Class A drugs

A
  • Ecstasy
  • LSD
  • Heroin
  • Cocaine
  • Crack
  • Magic Mushrooms
  • Amphetamines (if prepared for injection)
4
Q

Name examples of Class B drugs

A
  • Amphetamines
  • Cannabis
  • Methylphenidate (Ritalin)
  • Pholcodine
5
Q

Name examples of Class C drugs

A
  • Tranquilisers
  • Some painkilers
  • Gamma hydroxybutyrate
  • Ketamine
6
Q

What other conditions is drug abuse/dependence often linked with (co-morbidity)?

A
  • Depression
  • Anxiety
  • Schizophrenia (smoking might help)
  • PTSD
7
Q

What is the difference between psychological addiction and physical addiction?

A
  • Physical addiction is to self-medicate withdrawal symptoms eg. dysphoria, cramping, agitation
  • Psychological addiction drugs of abuse activate same brain systems as natural and so are ‘rewarding’ - much more complex.
8
Q

In what parts of the brain does self-stimulation act - ie the reward centres?

A
  • Median forebrain bundle
  • Ventral tegmental area

Also these (but less effective):

  • Prefrontal cortex
  • Nucleus accumbens
9
Q

What effect does cocaine have at the dopamine nerve terminal?

A
  • Cocaine blocks dopamine transporter (responsible for reuptake)
  • More dopamine in cleft binding to post-synaptic receptors
  • More reward/pleasure
10
Q

What is the effect of amphetamine on dopamine nerve terminal?

A

Amphetamines can get into the cell via the dopamine transporter and displace dopamine from synaptic vesicles, so called ‘reverse transport’.

They are also lipophillic and cationic so can get into cells and intracellular organelles quite easily eg. mitochondria.

11
Q

How can methamphetamine abuse lead to Parkinson’s?

A

Loss of dopamine transporter in human methamphetamine abuser -> neurotoxic -> can lead to early onset parkinson’s.

12
Q

What are the general treatments for addiction?

A
  • Psychological mainly
  • Disulfiram for alcohol
  • Methadone replacement therapy and opioid antagonists for heroin
13
Q

What are treatments for heroin dependence?

A
  • Mu opioid receptor activity
  • Agonists treatment can work, but antagonist would cause terrible withdrawal symptoms (only for overdose)
14
Q

Name a full agonist, a partial agonist and an antagonist for the mu opioid receptor

A
  • Full agonist - heroin
  • Partial agonist - buprenorphine
  • Antagonist - naloxone
15
Q

What are the types of drug tolerance?

A
  • Dispositional tolerance (metabolic)
  • Functional tolerance (cellular)
  • Context-specific tolerance (environmental)
  • Cross-tolerance
16
Q

What are the acute effects of alcohol on transmitter systems?

A
  • Increases GABA effects
  • Decrease excitatory transmitters (glutamate + aspartate)
  • Particular effect at NMDA receptors
  • 5-HT transmission altered
  • Inc release of endogeneous opiates
  • Inc mesolimbic dopamine tranmission
17
Q

What is the physiology of a hangover?

A
  • Formation of acetaldehyde (metabolism of alcohol)
  • Dehydration
  • Irritant effect on GI
18
Q

How does disulfiram (treatment) make you feel sick when taken with alcohol?

A
  • Disulfiram blocks the ALDH enzyme
  • -> build up of acetaldehyde
  • toxic -> nausea