Intro to pharmacology Flashcards
Definition of drug
- any substance taken by mouth, injection to muscle, blood vessel, cavity of body; inhaled, or applied topically to treat or prevent disease or condition
- restoring, correcting or modifying organic functions in man or animal
- drugs do not confer any new properties on cells/ tissues
Drug actions which are achieved by biochemical interactions b/w the drug and certain tissue components in the body (receptors) are divided into what 2 classes
- Pharmacokinetic interactions (how the body handles the drug)
- Pharmacodynamic interactions ( the drug’s effect on the body)
What is CPS
COMPENDIUM OF PHARMACEUTICALS AND SPECIALTIES
= a frequently updated list of every drug in the world
What is Pharmacology
the study of drugs and their effects on living organisms
what is pharmacokinetics
the processes which determine the concentration of a drug in the body over time; method drug enters body, moves around, breaks down and is eliminated. includes: -absorption -distribution -biotransformation -elimination
What is pharmacodynamics
the study of the actions of drugs on living tissues (cellular level)
- study of how drug acts on living organism
- drugs can only alter the functions of tissues, cannot cause a new function
What is Pharmacognosy
the study of natural drug sources
Define untoward effects
- the undesired effects that a drug has on the body
- a side effect that proves harmful to the pt
Define side effect
-unavoidable, undesired effects frequently seen even in therapeutic drug dosages
define orphan drugs
used specifically to treat a rare disease
-expensive drugs as not many ppl need them
Define indication
- medical condition or conditions in which the drug has proven to be of therapeutic value
- presenting sx and or hx that supports the decision to administer a drug
define contraindications
-presenting sx and or hx that negate the decision to administer a drug
= Do not give drug if pt has these
Define agonist drug
- drug or substance that binds w/ specific drug receptor & causes a physiological response
- drugs which bind to receptor sites and produce a cellular reaction
Define antagonist drugs
- the opposition btw 2 or more drugs
- a drug or other substance that blocks a physiological response or that blocks the action of another drug or substance
- a blocking agent, prevents other substances from producing an effect
- drug which binds to a receptor but produces no reaction
(ex. narcan reverses opiod od)
Can drugs be both agonist and antagonist
yes
Define efficacy
- power of drug to produce therapeutic effect
- drugs ability to initiate biological activity once bound
- differs btw ppl
Define affinity
-the tendency of a drug to combine w/ a specific drug receptor
define bolus
single, often times large dose of medication
define cumulative action
- a drug is administered in several doses, causing an increase effect usually due to the quantitative buildup of the drug in the blood
- toxic effects from repeated doses prior to adequate elimination from the body
Define depressant drug
-medication that decreases or lessens a body function or activity
Define habituation
- physical or psychological dependence on a drug
- process of becoming accustomed to a drug due to frequent use
- tolerance and dependence develop
- drug is no longer taken for therapeutic effects but rather to avoid unwanted effects of not taking the drug
Define drug dependence
- condition in which a person cannot control drug intake
- may be physiological, psychological, or both
Define hypersensitivity
- reaction to a substance that is more profound than seen in a population not sensitive to the substance
- allergic reaction
Define Idiosyncrasy
-individual reaction to a drug that is unusually different from that seen in the rest of the population
Define Potentiation
- increased or enhanced action of 2 drugs where total effect is greater than the sum of independent effects (1 + 1=4)
- one drug intensifies the other
ex: barbiturates and ETOH
Define refractory
- pts of conditions that do not respond to a drug are said to be refractory to that drug
ex: pt w/ VC that does not respond to lidocaine
Define Stimulant
-drug that enhances or increases a bodily function
Define synergism
- combined action of 2 drugs
- joint actions of 2 drugs to produce an effect neither one could alone
- the action is much stronger than the effects of either drug administered separately
ex: caffeine increases duration of analgesic effects of acetaminophen, NSAID’s and opioids
Define therapeutic action
-desired, intended action of a drug given in the appropriate medical condition
Define therapeutic dose (range)
-range of plasma concentration of a drug that produces the desired effects w/o producing lethal toxic effects
Define therapeutic threshold
-minimum effective concentration of a drug necessary to cause the desired response
therapeutic index
- difference between minimum effective concentration and toxic dose
- different w/ each drug
Define tolerance
-when pts are receiving drugs on a long-term basis, they may require larger and larger dosages of the rug to achieve therapeutic effect
Define onset of action
-interval btw the time a drug is administered and the first signs of effects
Define duration of action
-length of time that the plasma concentration stays above the minimum effective level for a therapeutic response
Define peak concentration
-highest plasma concentration achieved from a dose
define toxic dose
-plasma concentration at which a drug produces serious side effects
define relative potency
-relative amount of a drug required to produce the desired response
define half-life
- time required for body to fully eliminate 50% of a drug
- determines the frequency of dosing\
- takes 5-6 half lives for a drug to be eliminated
define summation
-aka additive effect, two drugs with the same effect are given together (~1+1=2)
Define tachyphylaxis
-quickly developing tolerance following repeat administration over short period of time
Define drug interaction
-effects of one drug alter the response to another drug
Define chemical name
-specifies the chemical structure of the drug
Define generic name
- nonproprietary name / does not belong to a particular company
- standard name assigned by national agency
- most commonly used
Define trade name
- brand or proprietary name
- name and registered trade mark a drug manufacturer gives to a drug
- always capitalized
Define official name
- usually same as generic followed by USP or NF
- used in official publications listing drugs conforming to standards
what are 6 things on drug label
- trade name
- generic name
- date dispensed
- doctor prescribed Rx
- dosage
- # of doses
what are 4 sources of drugs
- plants
- animals
- minerals
- laboratory (synthetic)
what are 4 components taken from plants to make drugs
- alkaloid
- glycosides
- gums
- oils
why are alkaloids the most important component
- react w/ acids to form salt
- salt is more readily soluble in body fluids
- usually end in -ine as in atropine, caffeine, nicotine
5 examples of plant derivative drugs
Opium plant: -morphine -heroine -codeine Atropa belladonna -Atropine Purple foxglove -digoxin
What is used when sourcing from animal and humans
body fluids or glands
-hormones, fats, oils & enzymes that act as catalysts
What source are vaccines from
animals
4 examples of animal derivative drugs
- insulin
- oxytocin
- cod liver oil
- pepsin
What are minerals or mineral products as sources for drug
- metallic and nonmetallic minerals provide various inorganic material not available from plants or animals
- mineral sources are used either alone or combined w/ other ingredients to yield acids, bases or salts
3 examples of mineral derivative drugs
- sodium bicarbonate
- calcium chloride
- magnesium sulfate
What are synthetic sources of drugs
- chem substances made in lab
- result of advancements in tech
- allows to produce greater quantities & develop safer drugs (less adverse reactions)
3 examples of synthetic dugs
- Lidocaine (xylocaine)
- Diazepam (Valium)
- Human insulin (Humulin)
11 components of a drug profile
- name
- classification
- mechanism of action
- indications
- pharmacokinetics
- side effects
- routes of administration
- contraindications
- dosage
- how supplied
- special considerations
What is classification of a drug
-broad group to which a drug belongs. knowing classifications is essential to understanding the properties of drugs
define mechanism of action
-the way in which a drug causes its effects; its pharmacodynamics
define dosage
amount of the drug that should be given
define supplied
Typically includes the common concentration of the available preparations; many drugs come in diff concentrations
define special conciderations
how drug may affect pediatric, geriatric or pregnant pts
What is Base Hospital Direction
- a BHP certifies medics to perform delegated acts (symptom relief)
- acts done under physicians license (medical director)
- medics cannot deliver drugs off duty; nor act under another MD license
- medic can be decertified if fail to follow guidelines
How to provide safe and effective Pt care
- know precautions, contraindications for all meds you give
- proper technique
- observe and document drug effects
- have current knowledge in pharmacology
- professional relationships with other healthcare providers
- understand pharmacokinetics and pharmacodynamics
- have current med references available
- take careful drug Hx
- evaluate compliance, dosage, adverse reactions
- consult with med direction as needed
10 steps to administering medications
- ID any allergies
- determine if order is consistent w/ training and scope of practice
- take and record vitals
- confirm order (med, dose, concentration, route)
- select and confirm med
- confirm med and order w/ partner
- check for cloudiness, particles, discoloration, expiry date
- 8 rights
- record drug, dose, route, time of admin
- properly dispose of sharps
8 Rights of med admin
Right:
- patient
- drug
- dose
- route
- time
- expiry date
- documentation
- to refuse
4 types of Pt’s for special considerations
- pregnant
- pediatric
- geriatric
- body mass
Special considerations with pregnant pts
- some drugs have adverse effect on fetus
- Teratogenic drug can deform or kill fetus
- drug given to mom reaches fetus and may affect breastfeeding baby
Anatomical and physiological changes in pregnant mother
Increased: CO HR Blood volume Decreased: protein binding hepatic metabolism BP
What is Placental barrier
- membrane layers that separate the blood vessels of the mother and fetus
- provides some protection to the fetus
What is Broselow Pediatric Emergency Tape
- used for size and drug calculations in infants
- placed along childs length to give a weight
- coded dosage charts and sizes for procedures
Pediatric weight formula
(age x 2) + 10
Considerations with pediatric patients
- higher proportion of water
- lower plasma protein levels (more available drug)
- immature liver/ kidneys (liver often metabolizes more slowly, kidneys may excrete more slowly)
Physiological effects of aging (geriatric pts)
Decreased: CO renal function (excretion) brain mass total body H2O serum albumin (protein binding) resp capacity GI motility liver function->biotransformation->delayed drug action Increased: body fat
Considerations with geriatric patients
- chronic disease states
- decreased plasma protein binding
- slower metabolism
- slower excretion
- dietary deficiencies
- use of multiple meds
- lack of compliance
Consideration Re: Age, weight, gender
Age: immature or decreased hepatic, renal function Weight: bigger spread over larger volume Gender: diff sizes diff in fat/water distribution
Other considerations
- environment
- fever
- shock
- genetic effects
- psychological factors
Pathology considerations
- Drug may aggravate underlying pathology
- Hepatic disease may slow drug metabolism
- Renal disease may slow drug elimination
- Acid/base abnormalities may change drug absorption or elimination
What do pharmacokinetics depend on
- body’s various physiological mechanisms to move substances across the body’s compartments
- can be through active or passive processes (mostly passive / diffusion or osmosis)
how does insulin facilitate the transport of glucose into the cell
carrier mediated diffusion or facilitated diffusion
What are the 5 steps in pharmacokinetic processes
- liberation
- absorption
- distribution
- biotransformation (metabolism)
- excretion
What is the absorption process
-a drug must find its way to the site of action via circulatory fluids (passive diffusion)
what is distribution process
-drug must be distributed throughout body
what is biotransformation process
-process of breaking down, or metabolizing, drugs
what is elimination process
- drugs must eventually be excrete from body
- usually via kidneys but also GI, sweat, saliva and breast milk
What is Liberation
-applies to drugs given orally
- release of drug from pill, tablet, capsule
- Dissolving of active drug in GI fluids
What are formulation factors that affect liberation / absorption
- tablet disintegration
- inert ingredient / solvent effects (coated to slow)
- solubility
- drug pH (acidic drug absorb faster)
- concentration
What are patient factors that affect liberation/ absorption
- absorbing surface
- blood flow
- environmental pH
- Disease states (shock, acidosis, peripheral vasoconstriction)
- interactions w/ food or other drugs
what is absorption rate of PO and transdermal drugs
~30 - 60 min
What is the rate of absorption of SL (sublingual), Vag (vaginal) and PR (rectal)
~15 - 30 min
What is absorption rate of topical drugs
~ 60 min
what is absorption rate of inhalation drugs and IV (intravenous)
~ 1 min
What is absorption rate of SC, IM and IO
~Several mins
What is distribution
-process whereby a drug is transported from the site of absorption to the site of impact
how are preferred routes of admin usually chosen
based on the rate of distribution for desired effect
4 factors that affect distribution
- cardiovascular function
- regional blood flow
- drug storage reservoir
- physiological barriers
Where is drug initially distributed
- to highly perfused body areas such as the brain, heart, kidneys, liver
- if CO decreases (shock, CHF) the drug distribution becomes slower ad less predictable
how can body store drugs
- by binding them to proteins present with in the tissue
- either a plasma carrier protein (plasma reservoir) or a storage tissue protein (tissue reservoir)
- will delay onset of action and prolong effects
How does time release work
drugs bind to plasma protein (albumin) and remain inactive
-as plasma concentration of free drug decreases, the bound drug will dissociate for use (concentration gradient)
4 Factors that affect distribution
- rate of perfusion
- plasma protein (albumin) binding
- accumulation in tissues
- ability to cross membranes (blood-brain barrier, placental barrier)
What is the blood-brain barrier
- a single layer of capillary endothelial cells that line the blood vessels entering the CNS
- cells have fatty sheath with no aqueous pores so drugs must be lipid soluble to pass through membrane
What drugs are easily transported by placental barrier
- steroids
- Narcotics
- Anesthetics
- Some antibiotics
it is not as selective as the blood-brain barrier
what is biotransformation
-process where the drug is chemically converted (metabolized) to a metabolite (another chemical)
What is purpose of biotransformation
- to detoxify a drug and render it less active
- liver biotransforms many drugs partially or completely
- all drugs absorbed by GI will go through liver first
What is the hepatic first pass event
- drugs given orally go through portal system first and liver before distributed to body
- can significantly metabolize drugs in first pass
- some drugs fully metabolize on first pass so cannot giv PO
why are IV doses much lower than PO
to adjust for loss of drug when it is metabolized on first pass
What are 2 effect from biotransformation
- transformation to less active metabolite
- enhancement of solubility
What happens to biotransformation when there is liver disease
- slows metabolism
- prolongs effects
- liver is the primary site of drug metabolism
What is Therapeutic threshold
- minimum effective concentration of a drug necessary to cause a desired response
- below this level drug will not produce a clinical response
- at some point above this drug can be toxic or fatal
What is excretion
elimination of toxic or inactive metabolites from the tissues either in original form or as metabolites
how can drugs be eliminated artificially
by direct interventions, such as peritoneal dialysis or hemodialysis
what is primary site of elimination
Kidneys
- mechanism dependent on:
- passive glomerular filtration
- active tubular transport
- partial reabsorption
- hemodialysis
What is the effects of renal disease on elimination
- slows excretion
- prolongs effects
What are 6 ways drug can be excreted
- kidneys into urine
- liver into bile
- intestines into feces
- lungs into expired air
- sweat glands (rare)
- mammary glands into milk
3 factors affecting elimination
- drug half-life
- accumulation
- clearance
What to note about shorter or increased biological half-life t1/2
- shorter t1/2 may need more frequent doses
- hepatic disease may increase t1/2
with a regularly administered drug reaches a constant total body amount or steady state after how many half lives
about 5
-once steady state reached drug concentration in blood fluctuates above and below avrg concentration
if time required to reach therapeutic blood concentration is too long how can you reach steady state
-initial loading dose then subsequent accumulation doses
What is clearance
- removal of drug from body
- slow clearance = slow rate of removal
- high clearance = rapid rate
What is risk with drug with low clearance rate
-may accumulate to a toxic concentration in the body unless it is administered less frequently or at lower doses
Consideration with drugs with high clearance rate
may require more frequent administration and higher doses than a comparable drug with a low clearance rate
What is Enteral drug route
-deliver meds by absorption through the GI tract
What are Parenteral drug route
-delivers meds via router other than the GI tract
What are the 5 Enteral routes
- oral
- orogastric (OG) / Nasogastric (NG)
- Sublingual (SL) (excellent absorption very vascular)
- Buccal (cheek/gum absorbed through mucous membrane)
- Rectal (PR) (only 1/2 drug taken goes through liver first so this route more predictable)
What are 8 Parenteral routes
- IV
- IO
- ET (endotracheal)
- Umbilical (newborns)
- IM
- SQ
- Inhalation
- Topical (percutaneous)
What are 10 drug forms
- liquid
- solid
- gas
- suppositories
- inhalants
- sprays
- creams
- lotions
- patches
- lozenges
Why are drug forms chosen in some cases
- because of drug interactions and reactions
- some forms are used to affect absorption rates into the body
5 subcategories of solid form drugs
- pills (spherically shaped)
- powders
- tablets (powder compressed into disk)
- suppositories (drug w/ wax that melts)
- capsules (gelatin container filled w/ powder)
What are 7 subcategories of liquid form drugs
- solutions (water or oil based)
- tinctures (alcohol extraction process)
- suspensions (doesnt dissolve in solvent)
- emulsion (suspension w/ oily substance in solvent)
- Spirits (volatile drug in alcohol)
- elixirs (alcohol and water solvent with flavoring)
- Syrups (sugar, water, drug solutions)
What are the actions of drugs
- Pharmacodynamics
- bind to a receptor site
- change physical properties
- chemically combine with other substances
- alter a normal metabolic pathway
How are drug receptors classified
by the effects they produce and may be further classified by specific effects
how do most drugs produce their effects
by either a drug-receptor interaction (agonist, antagonist, affinity, efficacy, types of receptors),
drug enzyme interaction, or
non-specific drug interactions
What is drugs effect on hormones, enzymes or metabolic functions
they can increase, decrease or replace them
-some drugs destroy or inhibit foreign organisms or malignant cells
What is drug-receptor interaction
-drug action begins after the drug binds to a receptor site on the cell membrane (key lock theory)
What is drug enzyme interaction
- normally enzymes bind to enzyme substrate molecules to produce an effect
- drug will mimic the substrate molecules and the enzymes combine with the drug instead
- blocks normal action or results in the production of another substance
How do drugs altering enzymes activity work
- alter processes catalyzed by the enzymes
- enzymes = biological catalysts (speed chemical reactions and are not changed themselves)
How can some drugs change cell membrane permeabillity
by blocking or opening sodium or potassium channels
What is non-specific drug interactions
-drugs penetrate into cells or accumulate in cell membranes to interfere with cellular function (ex. general anesthetics)
How do some drugs combine with other chemicals to affect body
- neutralize stomach acids (antacids)
- destroy/ inhibit bacteria or pathogens (antiseptic effect from alcohol)
- chelation of heavy metal (grabbing/ binding)
What are anti-metabolites
- enter biochemical reactions in place of normal substrate “competitors
- result in biologically inactive product
Define potency in relation to drug dose
- absolute amount of drug required to produce an effect
- more potent drug is the one that requires lower dose to cause same effect
Define Threshold (minimal) dose
-least amount needed to produce desired effects
Define maximum effect in relation to drug dose
-greatest response produces regardless of dose used
How is response to drug therapy usually assessed
by observing the pharmacological effect of the drug on physiological parameters
When do drug interactions occur
- whenever 2 or more drugs are available in the same pt
- the interaction can increase, decrease or have no effect on their combined action
6 variables influencing drug interactions include:
- intestinal absorption
- competition for plasma protein binding
- drug metabolism or biotransformation
- action at the receptor site
- renal excretion
- alteration of electrolyte balance
Name 6 adverse drug reactions that can cause temporary loss of function, permanent damage or death
- secondary actions/ effects
- Allergic/ hypersensitivity reactions
- Idiosyncratic reaction
- Mutagenicity
- Carcinogenicity
- Drug addiction
define secondary actions/ effects
- Side effect
- signs and symptoms of a drug reaction
- not the intended effect
Define allergic/ hypersensitivity reactions
-local or systemic effects due to hypersensitivity to the drug
define idiosyncratic reaction
- the drug reaction that is not expected (not normal for the population)
- unique to an individual
define Mutagenicity
- drug resistant mutants appear with common use of drug (ex. antibiotics)
- tolerance (decreased response to the same amount)
Define Carcinogenicity
-a drug which may cause cancer
Define drug addiction
behavioral pattern of:
- drug craving
- out of control usage
- overwhelming concern with obtaining drug supply
Define Cross Tolerance
-tolerance for a drug that develops after administration of a different drug
Define Tachyphylaxis
-rapidly occurring tolerance to a drug
Define cumulative effect
-increased effectiveness when a drug is given in several doses
Define drug dependance
-pt becomes accustomed to the drug’s presence in his body
define drug interaction
-effect of one drug alter the response to another drug
define drug antagonism
the effect of one drug block the response to another drug
Define summation
-AKA additive effect, 2 drugs with the same effect are given together (like 1+1=2)
define synergism
-2 drugs with the same effect are given together and produce a response greater than the sum of their individual responses (ex. 1+1=3)
Define potentiation
one drug enhances the effect of another
Define Interference
-the direct biochemical interaction btw 2 drugs; one drug affects the pharmacology of another drug
What are 8 other factors affecting pharmacokinetics
- onset of action
- peak concentration
- duration of action
- age
- weight
- gender
- time of administration
- route of administration
Define onset of action
the time when the drug is sufficiently absorbed to reach an effective blood level and sufficiently distributed to its site of action to elicit a therapeutic response
Define peak concentration
-as the body absorbs more of the drug, the drug concentration in the blood rises, more drug reaches the site of action, and the therapeutic response increases
Define duration of action
-length of time that the drug concentration is sufficient in the blood to produce a therapeutic response
What is age affect on pharmacokinetics
- young (immature liver and kidneys)
- elderly (decreased liver and kidney function
BOTH usually require smaller doses
What is weight effect on pharmacokinetics
- avrg adult dosages are based on a 150lb person
- dosage should be adjusted for significantly higher or lower weights
- water comprises approx. 60% of total body weight
What is gender effect on pharmacokinetics
- women usually smaller and have diff ration of body fat and water
- may require smaller doses
what is time of administration effect on pharmacokinetics
- drugs are absorbed more rapidly if GI tract is empty
- some drugs irritate the GI tract and should be taken w/ food
what is route of administration effect on pharmacokinetics
- IV route faster and needs lower dose
- PO slower and needs bigger dose
What are 4 sources of drug info you can refer to
- CPS (compendium of pharmaceuticals and specialties
- Health canada drug product database
- physician’s desk reference
- drug information
