NESC 3237 Lecture Notes - Caffeine, Sublingual Administration, Harmine

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Published on 17 Apr 2013
School
Dalhousie University
Department
Neuroscience
Course
NESC 3237
Professor
January 10th, 2013
January-10-13
2:35 PM
What are drugs?
They are any substance that alters the physiology of the body that is not a food or nutrient
Usually derived from plant compounds
Definition often accounts for the intention of the user
o For example if you are drinking coffee because you enjoy the taste, and the caffeine makes
it taste better, but you are not drinking it for the benefit of caffeine, then coffee is not
considered a drug
o But if you drink it to stay awake, then it's considered a drug
Examples:
o Vitamin C in pill form can be considered a drug
o But if you get it from an orange, then you are providing yourself nutrition
Psychoactive drugs
Are drugs that have an impact on the brain and the brain function
These effects on the brain alter perception, cognition, behaviour, mood
Many of these drugs can be used recreationally, to enhance mood, get high, ect.
Might use it recreationally but not for pleasure; escape their problems for a while
Or use them for ritual or spiritual purpose; many of the drugs used today recreationally have a
background of being used in a spiritual process
o Initially used so individuals could be better connected to spiritual world
Can also be used therapeutically
None of the drugs we talk about can fit very well into only one category
Every recreational drug we are going to be talking about, under certain context they all have
legitimate therapeutic value
o Drugs that work really well therapeutically usually tend to have a high abuse probability
Antidepressants and antipsychotics seem to be an exception to this however
Possibly because their effects are not acutely noticeable and take many
administrations over a period of time to make a difference
Drug names
They have a chemical name, which unless you're a chemist or pharmacist you're unlikely to use
Generic name
o Typically used in science beyond the basic chemistry
o We usually stick to this naming process
Trade names
o The names a company may give their drug (motrin = ibuprophen)
Formulation
Trade names often refer to the formulation, the way the medicine was made
Describing drug doses
Most commonly done by weight of drug in comparison to weight of subject
o Mg/kg
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Can also be measured by the concentration of the drug at the site of action
The dose response curve
Horizontal axis contains the dose concentration
Vertical axis contains frequency the drug effect occurs, or the extent of the effect
As dose increases, so does the extent of the effect
o Not a linear relationship, and isn't usually a linear relationship
ED50
Median effective dose; dose that is effective in half subjects
TD50
Median toxic dose; dose that causes toxicity in half subjects
o I.e. when it has detrimental effects
LD50
Median lethal dose; dose that kills half of the subjects
Don't usually do in humans obviously, but can use animal testing to gain some understanding as to
what this may be
*KNOW FOR EXAM, PROBABLY WILL COME UP
Drug safety
Therapeutic index
o TI = LD50/ED50 or more conservatively TD50/ED50
o The higher the number, the safer the drug is
Alcohol example
o TI is around 3.
o So legal drunk level is 0.08%, therefore LD50 level is triple that
If alcohol would be used as a therapeutic drug, it would never be approved if your ED50 was 0.08%
because TI = 3, which is very low
Potency
Can use when describing drugs with similar effect to one another
Not meaningful to say morphine is more potent than aspirin because they work via completely
different mechanisms
o Morphine may be much more effective than aspirin, but you can't correctly compare their
potency because of the different mechanisms
Effectiveness
The maximum effect a drug can cause
Primary effects and side effects
What a side effect is depends on the intention of the user
Weed example
o Someone smoked marijuana to get high, but discover after that they get the munchies
In this case the primary effect is to get high, side effect the munchies
o But if they use it to increase appetite because they are undergoing chemotherapy
The increased appetite would be the primary effect, but the feeling of being high is
the side effect
o Context is clearly quite important
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Drug interactions
When you use more than one drug at a time, the different substances can impact how the others
are experienced
Antagonism
o When one drug impairs the effects of the other
Additive
o When each drugs effect is the same as if used separately
Synergistic effects
o One drug causes in increase in effect of another
Novel effects
o The combination of two drugs creates a new effect that would have otherwise been
experienced
o Ayahuasca effect
If you take DMT on it's own, nothing happens
But if you take MAO inhibitor harmine on it's own, nothing happens
Both taken together generate hallucinatory effects
o One substance can change something in the brain that allows the other drug to cause an
effect in conjunction with it that it otherwise would not have on its own
Can interact both in terms of potency and effectiveness
Can occur at pharmacokinetic level
o What you body does to the drug (digesting, absorbs, ect.)
o Changes how quickly it's absorbed, where it goes, ect.
o Sometimes these interactions not only depend on what drugs you're using, but what order
you take them in as well
Such as a stimulant before you drink, versus after
And at the pharmacodynamic level
o How the drug effects the body
o Sometimes one drug can effect the pharmacodynamic effects of another
o And sometimes the drugs simply change the pharmacokinetic actions of the body
A lot of times drugs used in conjunction can interact with each other on a number of different
levels in a number of different systems. At pharmacokinetic and pharmacodynamic levels
Pharmacokinetics
Routes of administration
o How your body deals with the drug depends on how it got into the body in the first place
Absorption
o How the drugs get into the blood, sometimes it's injected right in, sometimes it must travel
there
Distribution
o Where in your body it goes
Excretion or elimination
o How the drugs leave your body
Anything that effects any of these, is going to effect the drugs performance on your perception,
behaviour, ect.
Routes of administration
Injections
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Document Summary

They are any substance that alters the physiology of the body that is not a food or nutrient. Examples: vitamin c in pill form can be considered a drug, but if you get it from an orange, then you are providing yourself nutrition. Are drugs that have an impact on the brain and the brain function. These effects on the brain alter perception, cognition, behaviour, mood. Many of these drugs can be used recreationally, to enhance mood, get high, ect. Might use it recreationally but not for pleasure; escape their problems for a while. Or use them for ritual or spiritual purpose; many of the drugs used today recreationally have a background of being used in a spiritual process. Initially used so individuals could be better connected to spiritual world. None of the drugs we talk about can fit very well into only one category.

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