CHAPTER TWO: BASIC CONCEPTS AND PROCESSES Flashcards
What are some “jobs” for cells and their components
Manufacture products and deliver them, differ tissues from each other, obtain energy, reproduce taking in materials and nutrients.
How do drugs affect cellular function
By first interacting with the cellular membrane
Define lipidphillic and lipidphobic
Lipidphillic: works with the lipid membrane
Lipidphobic: does not interact with the membrane
Where does systemic effect occur
The cellular level
What is pharmodynamics
Effect a drug has on the body
List the four ways drugs work
Substitute for missing chemicals, stimulate cellular functions, slow cellular functions, cell death
What do drugs chemically bind with
Receptor cells
What actions do receptor cells cause
Activation, inactivation or alteration of enzymes, change cell membranes, modification of the synthesis, release or activation of neurohormones
What are receptors made out of and where are they located
They are proteins that are on cell membranes
What defines how a drug works in terms of receptors
Level of attraction to the receptor and concentration of drug
Define agonists and antagonists
Agonists activate a response and antagonists stop a response
Give examples of drugs that do not act on receptor sights
Antacids, osmotic diuretics, anticancer drugs, metal chelating agents (excretion of toxic metals)
What is a nonspecific drug effect
Works on specific receptor type, but those receptors are found in multiple organs/tissues
What is a Nonselective drug effect
Acts on different types or receptors
Example: epinephrine
What is pharmokinetics
Movement of drugs through the body
What are the processes of pharmokinetics
Absorption, distribution, metabolism, excretion
Where does metabolism occur in the body
The liver
The process that occurs from the time the drug enters the body to the when it goes into the bloodstream
Absorption
Difference between active and passive transport
Active: moving from lower to higher concentration with energy
Passive: moving across the membrane without energy
What is the onset of the drug action determined by
Rate of absorption
What can effect absorption
Dosage, from of med, and administration, food and other meds
What are enteral medications
PO meds and meds that go through GI tubes
What can effect enteral absorption
GI movement, pH of the stomach, surface area of bowl (also pain and stress, by diverting blood flow)
What is parenteral medications
Does not go through GI
Examples: IV, IM, Sub Q
What effects rate of absorption in parenteral meds
The blood flow to area
- circulation and tissue type (fat is slower than muscle)
When would IV absorption be an issue
Vascular issues
Define distribution
Transport of drug molecules within the body, movement to tissues
What effects distribution
Blood circulation and volume, protein binding
What protein do drugs bind to in blood
Albumin
Difference between unbound and protein bound drugs
Protein bound drugs are inactive, only unbound drugs move through capillaries. The benefit is control of storage and distribution.
What does low protein binding mean
Short duration of action
Are drugs stored in muscle and fat
Yes
Hypoalbinemia
Monitor for excessive free drugs, can cause toxicity
How are ionized cells absorbed
Not well
How do drugs pass the blood brain barrier
Highly lipid soluble
What is metabolism
Inactivation by the body
Ways of metabolism
Changed into new chemicals, made inactive
Inactive prodrugs
Drugs that become active when metabolized
Where are drug metabolizing enzymes located
Kidneys, liver, RBC, plasma, lungs, GI mucus
What to do when metabolizing organs are damaged
Carefully medicate and decrease dose
What is the most common liver enzyme
P450 cytochrome
What is induction in terms of metabolism
Caused by chronic usage, metabolism is increase and a higher does needs given
Inhibition in terms of metabolism
Two meds that are metabolized by the same enzyme, meaning that toxicity is possible
Define excretion
Elimination of medication
Where are meds primarily excreted
Kidneys
What other ways to excrete medications
Skin, saliva, lungs, bile, feces
Ways excretion can be effected
- GFR (more than 60 is normal)
- urine acidity (4.5-8)
- BUN (10-20mg)
Creatine (0.7-1.4)
Variables influencing drug therapy
Clinical factors (age, etc.)
Pharmokinetics (absorption, etc.)
Administration (route)
Pharmodynamics (therapeutic window, side effects)
Variables influencing drug therapy
Clinical factors (age, etc.)
Pharmokinetics (absorption, etc.)
Administration (route)
Pharmodynamics (therapeutic window, side effects)
Onset
Time it takes to produce a response
Peak
Time to reach effective concentration
Trough
Lowest level of concentration before next dose
Duration
Length of time the concentration can produce a response
Plateau
Maintained level for fixed doses
First pass effect
When a high amount of the drug is gone before reaching the liver to be metabolized
Most common people in drug trials
White males 18-54
Polymorphism
Metabolism of medication is effected by genetics
Cross tolerance
Tolerant to another drug in its class so tolerant to the new drug as well
Do African Americans respond better to beta blockers or calcium channel blockers
Calcium channel blockers
Serum level
Lab measurement of amount of drug in bloodstream
Therapeutic index
Margin between effectiveness and toxicity, some drugs have a very narrow margin
Dosages, route of administration, drug-diet interactions, drug-drug interactions
Variables
Dosages, route of administration, drug-diet interactions, drug-drug interactions
Variables
Additive effects
Using two meds when one would work
Additive effects
Using two meds when one would work
Synergism
Combining drugs for a stronger effect
Synergism
Combining drugs for a stronger effect
Interference
When one drug effects another, normally metabolism
Displacement
Receptor has a stronger attraction to one drug so the other has a higher concentration in the bloodstream
When are adverse effects more severe
With a higher dose of
When are adverse effects more severe
With a higher dose
Common and serious adverse effects
- CNS (agitation, confusion, depression)
- GI (bleeding)
-hematologic (risk for bleeding)
-nephrotoxicity (damage)
-hyper sensitivity (allergic reaction) - serum glucose (raise blood sugar)
Teratogenicity
Dangerous for pregnant women
Black box warning
For meds that can cause life threatening effects
Pregnancy categories in terms of med safety
A- no damage
B- no studies on humans, but safe
C- no studies in animals OR humans
D- shown to have risks, only given in certain situations
X- not given
Important facts about toxicology
- fast treatment
-stable vitals
-prevent further damage through reducing absorption and increases elimination
-give antidotes