Class Notes (837,174)
Canada (510,151)
NESC 3237 (9)
Lecture

January 10th, 2013.docx

8 Pages
77 Views
Unlock Document

Department
Neuroscience
Course
NESC 3237
Professor
Sean Barrett
Semester
Winter

Description
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  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 ED 50  Median effective dose; dose that is effective in half subjects TD 50  Median toxic dose; dose that causes toxicity in half subjects o I.e. when it has detrimental effects LD 50  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 = LD50ED 50 more conservatively TD /E50 50 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 L50level is triple that  If alcohol would be used as a therapeutic drug, it would never be approved if your ED50as 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 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 o Can inject into a variety of different regions of your brain o Drugs being injected are usually dissolved in a vehicle such as distilled water o Injected through a hollow in a needle and left in a bolus o A catheter is often used when you're receiving many injections over time as it's left in your body o Cannula, a same idea as catheter but in your brain  Inhalation  Sublingual o In mouth, under tongue  Transdermal o Patch on skin  Orally o Most commonly used, but most complicated pharmacokinetically o Drinking, swallowing pill, ect Intravenous i.v.  Drug delivered directly into blood  Effects very rapid  Very easy to control dose of drug entering system because there is no metabolism of drug entering your system before it hits your blood. The dose you inject is the dose you get  Most efficient way to administer drug because you bypass other systems and get effect very fast  A problem with this is that if you miscalibrate your dose you're pretty much screwed o Very easy to overdose  A common cause of overdose is using more than one substance at the same time and cause pharmacokinetic or pharmacodynamic reactions (alcohol and prescription drugs) On the recreational level, people often share needles and cause the spread of disease quite often  Subcut
More Less

Related notes for NESC 3237

Log In


OR

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


OR

By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.


Submit