Week 2 - Drug Abuse P2 and Anxiety Disorders P1 Flashcards
How is the therapeutic index calculated?
LD50-ED50
What would be the fastest methods of drug use?
IV and Inhalents
What would be the slowest method of drug use?
Oral or Subcutaneous (slow release)
What is a ligand?
A chemical compound, a drug e.g., “a ligand that acts on a particular receptor”
What does affinity mean?
The attraction that a drug has for a receptor site
What does efficacy mean?
The ability for a drug to induce a response once bound to a receptor site.
A receptor agonist has ____ & _____ Whilst, a receptor antagonist has _____& not _____
affinity, efficacy, affinity, efficacy
What is one of the main problems of chronic drug treatments
Desensitisation/tachyphylaxis
Why do people deliberately take drugs? (give anatomy based reason)
Because of the realese of (neurotransmitter) dopamine. Specifically, the mesolimbic dopamine pathway (ventral tegmental area [VTA - in the mid brain] and the Nucleus accumbens [NA] -part of the basal ganglia] and path up to the prefrontal lobes) (i.e., reward circuit)
What is addiction?
A state characterised by a compulsiuon to take drugs periodically or continuosuly in order to experience the rewarding effects and avoid the discomfort of its absence.
what is physical drug dependence (Drug abuse)?
when not taking the drug produces withdrawal symptoms.
- In heroin dependence those symptoms are sweating, goosebumps, diarrhoea, muscular spasms, aches and pains.
- In alcohol and benzodiazepine dependence those symptoms are hypersensitivity to sound and light, anxiety, convulsions, coma or occasionally death (if withdrawal is too abrupt).
what is psychological drug dependence (Drug abuse)?
is when you crave the drug during abstinence and causes a high level of relapse.
Research suggests that craving may be due to increased _______ release from the prefrontal cortex to the nucleus accumbens. This is the major excitatory neurotransmitter in the brain. The anterior cingulated cortex and the amygdale both signal the nucleus accumbens using it when addicts are shown relevant drug paraphernalia. It has also previously been shown to be important in learned associations.
Glutamate
What are the drug treatments for heroin and how do they work?
(Heroin acts to increase dopamine through the mu receptor mostly in the nucleus accumbens and ventral tegmental area which makes it basically a really good pain killer.)
- Methadone - binds to the mu receptor (mu receptor agonist) and binds for longer than heroin would, reducing the ability for heroic to bind. It has a slow mechanism and a small effect so you don’t get the rush like you would with heroin
- **Buprenorphine **- binds to the mu receptors but has less efficacy (a partial agonist) than methadone
- **Naloxone **- a mu receptor antagonist (competitive binding) that blocsk heroin activating mu receptors to release dopamine . often used in emergencies to treat an overdose, but compliance is a problem in drug abuse treatment.
- **Buprenorphine + Naloxone **- aimed at modifying how heroin gets to the mu receptor whilst trying to maintain compliance
how does heroin affect the user?
Heroin acts to increase dopamine through the mu receptor mostly in the nucleus accumbens and ventral tegmental area which makes it basically a really good pain killer.
What are the drug treatments for alcohol and how do they work?
- Acamprosate (Campral) is an NMDA (a type of Glutamate receptor) antagonist and reduces cravings.
- Naloxone blocks the effect of alcohol on mu receptors.
- Disulfiram (Antabuse) forces abstinence by making alcohol use very unpleasant. If you take alcohol with disulfiram you will be violently ill through a chemical gastrointestinal reaction. It is used to detoxify alcoholics.