2 - routes of administration Flashcards
how much do genetic factors account for in the risk for addiction
50%
do monozygotic or dizygotic twins have a more similar rate of addiction
monozygotic
do kids have addiction habits more like birth family or adopted family
birth family
what is epigenetics
change in expression or regulation in genes
how do epigenetics play a role in addiction
long term neuroplasticity, they can be passed on
what did they find with the “candidate” genes (DAT, DRD2, OPRM1)
contradicting results, not just 1 gene has a role in addiction
what do genome wide associates studied (GWAS) do
compare as many genes as possible between dependent and non dependent subjects
do you need to know about certain candidate genes before doing a GWAS
no, because results of GWAS will show differences at any genetic location present
what do GWAS tell us about addiction (3)
- many different genes are involved (polygenic)
- unexpected genes emerged
- genes overlap with different drugs
what are some of the unexpected types of genes found in GWAS
genes that are involved in neuronal adhesion
what do neuronal adhesion genes do
help with learning and plasticity
what does the link between the drug-GWAS and the neuronal adhesion genes mean
that drug dependence may be a learning problem
do certain genes only cause addiction susceptibility to only 1 drug
no, gene changes make you susceptible to many different addictions in general, not just 1 drug
why is it hard to reproduce studies that link addiction to genetics
it is hard to define if someone is truly dependent and there is a large spectrum of dependence (people need different amounts of drug to getting to the point they want to achieve)
why are GWAS for drugs critizied
lots of stats involved, easy to make a mistake there
also people argue whether there are any truly significant variations in genes that lead to abuse/dependence
what are the 4 major routes of administration
mouth
injection
inhalation
insufflation(snorting)
what route of administration has the fastest route to brain
inhalation
what route of administration has the second fastest route to brain
injection
what route of administration has the third fastest route to brain
snorting
what route of administration has the slowest route to brain
ingestion
what route of administration has the highest peak of concentration in the brain
inhalation slightly higher than IV
do slower administration methods have a high concentration peak
no
do faster administration methods have a high concentration peak
yes
do slower administration methods have an intense high
no
do faster administration methods have an intense high
yes
do slower administration methods last a long time in brain
yes
do faster administration methods last a long time in brain
no
what is bioavailability
the fraction of drug that ends up in circulation
what is the bioavailability for IV drug intake
100%
what are the 2 main properties of drugs that make them easily absorbed in the gut
lipid soluble
uncharged
what is first pass metabolism
when drugs are metabolized by enzymes in the liver or gut before entering general circulation
why do we eventually sober up from drugs but why isnt it immediate
many drugs arent 100% metabolized by the liver the first time through, so thats why it takes time
what are the main enzymes in the liver that provide the majority of metabolism
cytochrome P450 enzymes
-CYP
does intravenous, intramuscular or subcutaneous injections have 100% bioavailability
only IV
why does injection have high bioavailability
avoids first pass metabolism
how does rate of injection affect peak height
pushing the drug faster makes the peak higher
where is a good place to inject if there are drugs with contaminants and why
blood vessels because they are insensitive in irritants
what are the downsides to injecting into veins (2)
veins collapse due to inflammation and risk of disease/infection
is intramuscular or subcutaneous quicker at absorbing
intramuscular because of better blood supply to the muscle
rate thigh, glutes and deltoid in terms of fastest absorption rate
fastest is deltoid, then thigh, then glutes
can IM or subQ inject more volume
IM
does IM or subQ have a higher chance of irritation
subQ
why does inhalation occur faster than IV (for drugs to get in brain)
inhale - lungs to brain
IV - vein to heart to lung to brain
what is a difficulty in inhalation
hard to control doses
how can snorting and chewing avoid first pass metabolism
if you use the mucous membranes in the mouth or nose (cocaine or chewing tobacco)
what kind of drugs have the lowest abuse potential
hallucinogens
what kind of drugs have the highest abuse potential
IV or smoked things
what are the 4 main things in pharmacokinetics
ADME
absorption, distribution, metabolism and excretion
are drugs free or bound to plasma protein
both
what 3 factors determines how much drug is in the plasma
rate of absorption, excretion and metabolism
how are drug removed from the body
excretion and/or metabolism (some drugs are excreted unchanged/unmetabolized)
what is a drug half-life?
the time it takes for the concentration of drug in plasma to fall 50%
what does the dose response curve describe
amount of drug in system and the response it produces /or %of a population in affects
why is there overlap in the curves in the dose response curve
because some people are affected quicker than others
what is TD50
the concentration of drug that is toxic in 50% of subjects
what is ED50
the concentration that produces the desired effect in 50% of users
what is theraputic index formula
LD50/ED50
the ratio
what does theraputic index measure
how different a dose must be for the effective dose and the lethal/toxic dose
measures safety of a drug
what does a low therapeutic index mean
not a big different in dosage from ED to TD (easier to overdose)
what does a high therapeutic index mean
big different in dosage from ED to TD (harder to overdose)
how can TI change when other drugs are present
they can drop dramatically
