Pharm final 2 Flashcards
The inventor of the drug
Brand name
ED50 is the dose of the drug that produces
An effect in 50% of the population
TD50 is the dose of the drug that produces
Toxicity in 50% of the population
Formula for therapeutic index
TD50/ED50
Larger TI means the drug is
Safer
If a drug has a low TI, then there’s only a __ gap between what’s effective and what’s toxic
Small
With a Los TI, if the dose is off by even a small amount you could have
Toxicity
2 we’ll know drugs with low TI
Warfarin and phenytoin
If switching from generic to brand name, you need to be careful because
The potency could vary between the two
Drugs take something the body already does and alters it, but it doesn’t
Gives new functions
Process of a drug has three parts
- Delivered to tissue
- Effect on tissue
- Eliminated from body
Pharmacokinetics
What does your body do to a drug
4 parts of pharmacokinetics (similar to the drug process slide but little more details)
Absorption
Distribution
Biotransformation
Excretion
Absorption is the site of administration to
Plasma
Distribution is plasma to site of action and
Other sites too because drugs are stupid and don’t know exactly where to go
Biotransformation is ___ altering the drug
Chemically
Excretion is
Removal of drug
Word for “how does the drug work”
Pharmacodynamics
What does your body do to a drug
Pharmacokinetics
Phrase describing that the form in which the drug is taken can impact the pharmacokinetics
Pharmaceutical phase
Pharmaceutical phase aka
Route and form
Pharmaceutical phase doesn’t change what the drug ___ but it changes the speed at which it works
Does
Examples of drugs that work by targeting enzymes
ACE inhibitors and aspirin
Examples of drugs that work by altering cell membrane activity
Local anesthetics
Examples of drugs that work by targeting receptors
Antihistamines and beta blockers
Examples of drugs that work by neutralizing small molecules
Antacids
Absorption, distribution, and elimination depend on the ability of a drug to cross the
Cell membrane
__ soluble drugs cross the membrane faster
Lipid soluble
Most common way that drugs move across the cell membrane
Diffusion
Diffusion is driven by
Concentration gradients
How much of the active drug is available to tissues after being administered
Bioavailability
IM has a ___ bioavailability than oral
Higher
In which part of the 4 parts of Pharmokinetics does the the drug exert its effects
Distribution
During biotransformation, the body chemically alters the drug in order to ___ it
inactivate it
Does pH affect absorption
Yes
Weak acids are better absorbed in ___ environments
acidic
Bases are better absorbed in ___ environments
basic
Most drugs are best absorbed by which organ
small intestine
99% of the time, higher drug concentration means ___er absorption
higher
constant % of the drug released at set intervals
1st order pattern
constant amount (i.e. in milligrams) released at set intervals
0 order pattern
An example of 0 order is the use of __ ___ capsules
time released capsules
Enteral route is anything to do with the _ _ tract
G I
Enteral route is not the quickest or most ___
reliable
Stomach has no significant
absorption
Not even __ is absorbed in the stomach even though it’s acidic
aspirin
Rectal administration is good because is very ___ but bad bc it has small ___
vascular, surface area
Another advantage of rectal is that it bypasses the
first pass effect
An important concern of IV is that you don’t go
too fast
Intrathecal is aka ___ aka ___ space
spinal aka subarchnoid space
For an intrathecal aka spinal you need to monitor
BP
Medication delivered by an epidural most travel through the
meninges
Effects of an epidural are ___er than a spinal
slower
Medication delivered by the ears, eyes, skin, nasal mucosa
topical
One factor effecting distribution is __ __ binding
plasma protein
Some drugs have a high affinity for binding with
protein
If a drug is stuck to a protein it can’t get to the
tissue
2 drugs that almost completely bind to protein
warfarin and diazepam
Being bound to a protein is ___ (it changes)
dynamic
Drugs that bind to protein have a ____er duration of action. The protein slowly releases the drug.
longer
You have a drug that’s bound to protein. You add a 2nd drug that also binds. This causes some of the 1st drug to
release from the protein
Only __ soluble substances can cross the BBB
lipid soluble
Pregnancy category A
safe for pregnant women
Pregnancy category X
unsafe for pregnant women
Biotransformation inactivates a drug by making it more
water soluble
The water soluble a drug is the more easily it is
eliminated
A series of enzymes in the liver used for eliminating drugs
p450
p450 enzymes can be ___ed or ___ed by certain drugs
inhibited or induced
The basis for a lot of drug interaction is the __ enzyme
p450
Metabolism is a synonym for
biotransformation
A higher dose is needed for oral medication because of the
first pass effect
major organ of excretion is
the kidneys
With ethanol, once you reach saturation level
only a set amount can be excreted at a time
A saturation level, ethanol kind of follows a __ ___ pattern
0 order
Urinary __ can be altered to enhance excretion of poisons or medications taken in toxic doses
pH
To enhance excretion of an acid, make environment more
basic
The time it takes to reach the MEC (minimal effective concentration)
Onset of action
