Chapter 1 Flashcards
the movement of gases from inhaled air into the blood and vice versa is called ___
diffusion
true or false: one drug can have multiple ED50s
true, as a drug can have multiple effects and each effect may have a different ED50
When are lot numbers used to name drugs?
Before they are given a generic or trade name. Drugs that remain labeled with their lot name are usually those which do not get dispersed to the public and remain in testing scenarios
what are the four parenteral administration routes not via the CNS
- Subcutaneous
- Intramuscular
- intraperitoneal
- intravenous
how does peroral administration work
drugs are absorbed into the body via the gastrointestinal tract after being swallowed
absorption, distribution, and elimination make up ____
pharmacokinetics
combining drugs has an effect beyond what would be expected based on individual components
superadditive effects/potentiation
how a drug gets into the blood stream
absorption
true or false: the high from weed can be a side effect
true. if someone is taking it for increased appetite and do not want the high, the high is considered a side effect as it is not intended or wanted
the excipients and active ingredient(s) are combined in a particular way that is known as:
the drug formulation
why can you not know if a drug will ionise with only knowing if its an acid or a base
because you don’t know where it’s pKa is
caffeine is a base, but it’s pKa is so shifted that it remains intact in the stomach. you need to know both pKa and the shape of it’s curve (acid or base) to determine if it will ionise or not
How do things get through the lipid bilayer without lipid solubility
Ions can pass via specialised systems, but these only exist for ions you use everyday such as sodium or potassium
true or false: just because a drug gets into the body doesn’t mean it will have an effect
true, it will not have an effect if it doesn’t reach its site of action
Drugs administered this way are injected into the subarachnoid space in the nervous system
Intrathecal
what is inhalation of powder into the nose called
intranasal administration or insufflation
when one substance diminishes the effect of another and pushes the drug response curve to the right
drug antagonism
why are some drugs to be taken with food
taking it with food generally slows absorption, whereas taking it on an empty stomach allows it to pass to the intestines quickly and be absorbed much faster
amount of a drug needed in order to have a lethal effect in half of patients tested
LD50 -> Lethal Dose
what is it called when a drug is absorbed through the skin
transdermal administration
Consumed to get high
recreational
How is systemic administration doses determined
Divide by the weight of the organism receiving the drug
i.e. Mg/Kg or G.Kg
how does the chemical name work
based on the molecular structure of the drug molecule. tells how parts are connected
heroin administration is done via what method
subcutaneous injections
what are the steps of alcohol metabolism
ethanol is broken down into acetaldehyde by alcohol dehydrogenase
acetaldehyde is broken down into acetate by aldehyde dehydrogenase
List the naming schemes for drugs
- Chemical name
- Generic name
- Trade name
- Lot number
why do highly lipid soluble drugs remain in the blood stream so long
body fat acts as a sponge, absorbing the drug. while this diminishes the effect, it slowly releases back into the blood over time
how long does it take for drugs administered via I.V. to take effect
it is distributed very quickly, reaching the brain in seconds
what are sites of action
most drugs only have influence at specific and limited places in the body. they do not have an effect on all body tissue
What is the purpose of depot injections
The drug will diffuse slowly over a long period of time. This is helpful with drugs like antipsychotics where chronic compliance may be an issue
for this type of injection, the membrane is one cell deep with pores and is easier to move through than the lipid bilayer
subcutaneous
Why is nicotine consumption higher under stress
stress increases urine acidity which means more nicotine is broken down and cannot be reabsorbed
What are the two methods of drug dosing
Systemic administration and Central nervous system administration
bioavaillability
whether a drug gets to its site of action, how fast it gets there, and how much gets there
where are subcutaneous injections usually performed (when not self administered)
for lab animals: between the shoulders
for humans: arm or thigh
Substances that impact the nervous system, altering mood perception or level of consiousness
psychoactive drugs
drug concentration in the blood of a fetus usually reaches ___% to __% of the mothers within 5 minutes
75%-100%
true or false: metabolites can be more toxic than the drug
true
what happens if you administer a lipid soluble drug in an oil based vehicle
the rate of absorption is slowed, allowing the drugs effects to last several days
how are drugs administered through the gastrointestinal tract when oral administration is not possible
intrarectal administration. Suppositories placed in rectum so the drug can absorb that way
the result of special cells in the nervous system that are wrapped around capillaries to block pores
the blood brain barrier
what is the difference between the trade name and the generic name
the trade name is solely for marketing purposes and doesn’t have anything to do with what a drug does, unlike the generic name which classifies drugs with their suffixes
what is the main feature of intramuscular administration
the drug doesn’t go into the blood stream as quickly
true or false: inhalation allows for more precision with drug levels in the blood
true
if the concentration of drug in inhaled air is higher than in the blood, the drug will move from the air into the blood. additionally, the drug will move out of the blood and be exhaled so that concentration in the blood matches that of the air
Drugs administered this way are injected into the peritoneal cavity
intraperitoneal administration
For intramuscular depot injections, the drug must be lipophilic. What does this mean?
It must be highly lipid soluable
Grapefruit juice’s effect on many drugs is an example of what type of interaction
Potentiation/superadditive effects
Why can generic drugs names be complicated
There are some cases where different parts of the world have different names for the same drug, particularly between the US and Britain, despite the WHO attempting to harmonise names
What are depot injections
a drug is dissolved in high concentration in a viscous oil and injected into a muscle, typically the ass
Why are drug amounts so much smaller in central nervous system administration
Unlike systemic administration, the drug does not get distributed throughout the body in the blood stream in order to reach the brain. It goes there directly, and thus none of it gets metabolised first
You only need about 1000th of the amount when administered directly like this
drugs administered this way are absorbed through membranes in the cheeks
buccal membrane administration
Why is inhalation administration so effective
Some of the substance reaches the brain without being subject to metabolism in the rest of the body
Epidurals are administered using which method
Intrathecal
The maximum effect a drug can produce, regardless of how high the dose
Efficacy
what is the functional unit of the kidney
nephrons
Why are generic names helpful
They can be used to identify the class of a drug, as those in the same class often have the same suffix
i.e. benzodiazepines usually ending in -am
how the drug is broken down and leaves the body
elimination
admin through this method means the drug is injected to form a bolus just under the skin
subcutaneous
lack of or low levels of what enzyme cause an alcohol “allergy”
aldehyde dehydrogenase. this causes acetaldehyde to build up in the system
True or false: intracerebral administration differs in difficulty based on the specific structure
true, it is harder for weirder shaped structures such as the hippocampus
where a drug goes in the body
distribution
when a drug goes to the liver before anywhere else in the body
first pass metabolism
the lipid tails are hydro_____
hydrophobic (water repelling)
True or false: all formulations with the same active ingredient are equal
False. Some formulations may dissolve at different rates
What is the Dose Response Curve
a wide range of doses may be given of a drug. the curve is a range that goes from so low there is no detectable effect to so high that increases have no further effect
Why are the chemical names of drugs sometimes complicated
there are different numbering conventions which can lead to the same drug having multiple chemical names
_____ administration is done via injections into the skin
parenteral
what happens to a drug after it is swallowed
it goes straight to the stomach, which then produces enzymes to turn food pieces into liquid that is absorbed by the intestines
the dose needed in order to produce an effect in half of the subjects tested
Effective Dose -> ED50
What is the primary effect of a drug
the intended result. What you’re taking it for
What is the side effects of a drug
any unintended effects of a drug that may or may not be harmful
if the dose response curve is shifted right you need ____ (more/less) of the drug and the drug is _____ (more/less) potent
- more drug
- less potent
what is the enzyme that gets blocked by grapefruit juice
CYP3A4
true or false: drugs cannot be absorbed through the stomach
false; if a drug is soluble in gastric fluids and doesn’t get broken down by digestive enzymes it can be absorbed via the stomach however this is less effective than through the intestines
describes the molecular structure of the drug molecule
chemical name
What is a drug?
Exogenous substance that alters physiology from small doses
the ____ tells you what pH at which half of the drug will ionise
pKa
what is the suffix of most enzymes
-ase
Why do smaller animals often need a higher dose than humans
Smaller organisms often have higher metabolic rates and therefore drugs are broken down much faster
what is the difference between smoke and gas inhalation
smoke particles do not revaporise like gas does and is therefore not exhaled, meaning the drug stays in the body until eliminated some other way
the lipid heads are hydro____
hydrophilic (water loving)
Consumed to treat a disorder or medical condition
Pharmeceutical
What are the three ways of parenteral CNS administration
- Intrathecal
- Intracerebroventricular
- Intracerebral
When is central nervous system administration used
when administered directly into the spinal cord or the brain
“when the elimination of a drug changes with concentration is its said to have:”
first order elimination kinetics
When is systemic administration used
For any drug that has the potential to be distributed throughout the body
What is the traditional way to define a drug and why don’t we use it
Traditionally something that alters the physiology of the body, however that is broad and includes substances like food and water
the product of metabolism that can vary in effects
metabolites
this method entails injecting directly into brain tissue to target a specific structure
intracerebral
the large protein molecule creates a channel allowing a non-lipid soluble molecule to pass
passive transport mechanism
keeps balance between salt and water levels
kidney
if the dose response curve is shifted left you need ____ (more/less) of a drug and the drug is _____ (more/less) potent
- less drug
- more potent
when one substance increases the effect of another, pushing the drug response curve to the left
drug agonism/additive effects
Dosing based on how much of a drug per [weight measurement]
Systemic Administration
why is it challenging for drugs to be administered transdermally
they often have to be formulated for it, as most naturally cannot pass through the keratin in the epidermis which is very tightly knit
cross section of cell membrane
lipid bilayer
if one drug has no effect alone but increases the effect of a second ____ is occuring
potentiation
what happens when a drug is highly lipid soluble
it may appear in the blood stream long after use
how long does it typically take for a drug to be absorbed through the muscles capillaries in intramuscular administration
roughly an hour
True or false: according to the dose response curve, a small change will have the same effect in a low dose or a small dose
False. a small change in low doses can have a big effect, and an equally small change in a large dose has no effect
Drugs administered this way are “mainlined,” injected directly into the bloodstream
intravenous administration
Why is 10 a bad therapeutic index
You want a larger gap between the LD50 and the ED50 because people may not fit the average. Being at the far end of one number does not mean they will be for the other. They may need more to be effective, but have the same lethal dose, etc.
although it is fast an effective, why is I.V. not always the best route
if a vein is used too frequently is will collapse and stop carrying blood
How are I.V. injections simulated in animals like rats
using tools like catheters
How much of a drug you need in order to produce an effect
potency
why should I.V. not be used for recreational drugs
they may contain contaminates that do not dissolve and then get lodged in the bloodstream, causing damage to blood vessels in organs like the lungs or eyes
What is the peritonea
the sac containing visceral organs
How are drug doses determined with central nervous system administration
Absolute amount of the drug
what is the therapeutic window
the level in which the drug levels are high enough to produce an effect, but not high enough to cause unwanted effects
what are the two methods of oral administration
peroral and buccal membranes
true or false: all drugs have a half-life
false. some, like alcohol, decrease at a consistent rate
What is the difference between potency and efficacy of a drug
potency is how much you need in order to get the effect, efficacy is what the maximum effect is at any dose
i.e. morphine has higher efficacy than tylenol for pain relief
What are excipients
other ingredients such as fillers, binding agents, etc. that are combined with the active ingredient for a drug
this method entails being injected into a ventricle in the brain which then distributes the drug
intracerebroventricular
how do the curves of drugs administered orally differ compared to drugs administered via inhalation
absorption for inhalation is very steep, so it enters the body fast and therefore leaves fast. oral administration enters the bloodstream slower and is slower to be eliminated
if only 3% of a drug is lipid soluble, what happens to the rest?
as soon as that 3% is diffused into the blood, 3% of what is remaining will lose it’s charge and that will diffuse. this will repeat
What happens when something like weed is smoked
the active ingredient is inhaled into the lungs and makes contact with the moist surface of the lungs where it then diffuses into the bloodstream
What is the therapeutic index
The LD50 divided by the ED50
What is the tool used for CNS parenteral administration called
a cannula, which is like a catheter. it is a rigid tube that resembles a needle
why does age impact drug metabolism
enzymes systems are not fully functional at birth and develop more with time
in this method of administration, the needle is inserted into a muscle, leaving a bolus
intramuscular
a range
of blood concentrations of a
medicine above a level that is
ineffective (therapeutic level) and a
level that has toxic side effects (toxic
level)
therapeutic window
true or false: the tolerance to toxic effects of morphine develops slower than tolerance to its pain relief effects
true
