the process by which the body inactivates or biotransforms drugs
Metabolism or Biotransformation
primary site of metabolism
liver
Most drugs are inactivated by liver enzymes and are then converted or transformed by hepatic enzymes to ____________ or __________ substances for excretion.
inactive metabolites, water-soluble
When the drug metabolism rate is decreased excess drug accumulation can occur and lead to _______.
toxicity
The ____________ of a drug is the time it takes for one half of the drug concentration to be eliminated.
half-life (t 1/2 )
___________ and __________ affect the half-life of a drug.
Metabolism, elimination
The main route of drug elimination is through the ____________.
kidneys (urine)
Other routes for drug elimination
Bile
Feces
Lungs
Saliva
Sweat
Breast Milk
What do the kidneys filter?
unbound drugs, water-soluble, drugs that are unchanged
The ______ eliminate volatile drug substances and products metabolized to carbon dioxide (CO2) and water (H2O).
lungs
The urine pH influences drug excretion. Urine pH varies from ___ to __.
4.5, 8
Acidic urine promotes elimination of __________, and alkaline urine promotes elimination of ___________.
weak base drugs, weak acid drugs
With a kidney disease that results in decreased glomerular filtration rate (GFR) or decreased renal tubular secretion, drug excretion is increased. True or False?
False, drug excretion is slowed or impaired
A decrease in GFR results in an increase in _____________ level and a decrease in _______________.
serum creatinine, urine creatinine clearance
______________ is a waste product that your kidneys remove from your blood.
Urea nitrogen
Higher than normal BUN levels may be a sign that your kidneys aren't working well. True or False?
True
Common tests used to determine renal function
Creatinine clearance (CLcr)
Blood urea nitrogen (BUN)
___________ is a metabolic by-product of muscle that is excreted by the kidneys.
Creatinine
The _______________________ compares the level of creatinine in the urine with the level of creatinine in the blood.
creatinine clearance test
Lower values (creatinine clearance) are expected in older adult and female patients because of their ________________.
decreased muscle mass
the study of the way drugs affect the body
Pharmacodynamic
Drug response can cause a primary or secondary physiologic effect or both. The _____________ is desirable, and the ___________ may be desirable or undesirable.
primary effect, secondary effect
example of a drug with primary and secondary effect
diphenhydramine (Benadryl)
__________ is the time it takes to reach the minimum effective concentration (MEC) after a drug is administered.
Onset of action
_____________ occurs when the drug reaches its highest blood or plasma concentration.
Peak action
______________ is the length of time the drug has a pharmacologic effect.
Duration of action
If the drug plasma or serum level decreases below threshold or MEC, adequate drug dosing is not achieved. True or False?
True
Too high a drug level above the minimum toxic concentration (MTC) can
result in _________.
toxicity
Drugs act through receptors by binding to the receptor to produce (initiate) a response or to block (prevent) a response.
Receptor Theory
The activity of many drugs is determined by _____________________.
the ability of the drug to bind to a specific receptor
The better the drug fits at the receptor site, the more biologically active the drug is. True or False?
True
Most receptors, which are ____________, are found in cell membranes.
protein in nature
Drug binding sites are primarily on:
Proteins
Glycoproteins
Proteolipids
Enzymes
4 receptor families
kinase-linked receptors
ligand-gated ion channels
G protein-coupled receptor systems
nuclear receptors
The ______________ is the site on the receptor at which drugs bind.
ligand-binding domain
The ligand-binding domain for drug binding is on the cell surface. The drug activates the enzyme (inside the cell), and a response is initiated.
Kinase-linked receptors
The channel spans the cell membrane and, with this type of receptor, the channel opens, allowing for the flow of ions into and out of the cells. The
ions are primarily sodium and calcium.
Ligand-gated ion channels
There are three components to this receptor response: (1) the receptor, (2) the G protein that binds with guanosine triphosphate (GTP), and (3) the effector that is either an enzyme or an ion channel.
G protein-coupled receptor systems
How does G protein-coupled receptor systems work?
drug ---activates-> receptors ----activates-> G protein ---activates-> effect
Found in the cell nucleus (not on the surface) of the cell membrane. Activation of receptors through the transcription factors is prolonged. first three receptor groups, activation of the receptors is rapid.
Nuclear receptors
Drugs that produce a response are called __________
agonists (e.g. Epinephrine)
Drugs that block a response are called ___________.
antagonists (e.g. Atropine)
The effects of an antagonist can be determined by the inhibitory (I) action of the drug concentration on the receptor site. True or False?
True
________________ are located in the bladder, heart, blood vessels, stomach, bronchi, and eyes.
Cholinergic receptors
A drug that stimulates or blocks the cholinergic receptors affects all
anatomic sites of location. Drugs that affect various sites are ____________ and have properties of nonspecificity__________.
nonspecific drugs, nonspecificity
Drugs that affect various receptors are ___________ or have properties of ____________.
nonselective drugs, nonselectivity
4 categories of drug action
stimulation
inhibition or killing of organisms
replacement
irritation
The ____________ estimates the margin of safety of a drug through the use of a ratio that measures the effective (therapeutic) dose (ED) in 50% of people (ED50) and the lethal dose (LD) in 50% of people (LD50).
therapeutic index (TI)
(TI) The closer the ratio is to 1, the greater the danger of toxicity. True or False?
True
The __________________ of a drug concentration in plasma is the level of drug between the minimum effective concentration in the plasma for obtaining desired drug action and the minimum toxic concentration (the toxic effect).
therapeutic range (therapeutic window)
_____________ is the highest plasma concentration of drug at a specific time. This indicates the rate of absorption.
Peak drug level
If the drug is given orally, the peak time might be _______ hours after drug administration.
1 to 3
If the drug is given IV, the peak time might occur in ___________.
10 minutes
If a peak drug level is ordered, a _________ should be drawn at the proposed peak time, according to the route of administration.
blood sample
The __________ is the lowest plasma concentration of a drug, and it measures the rate at which the drug is eliminated.
trough drug level
Trough levels are drawn immediately before the next dose of drug is given, regardless of route of administration. True or False?
True
When immediate drug response is desired, a large initial dose, known as the __________, of drug is given to achieve a rapid minimum effective concentration in the plasma.
loading dose
___________ is the process by which the minimum effective concentration level for digoxin is achieved in the plasma within a short time.
Digitalization
The therapeutic goal is achieved. The drug does what is supposed to do
Desired Effect
Are mild but annoying response to medication. Ex. nausea and drowsiness.
Side effect
Are more severe symptoms or problems that arise because of the medication. Ex gastric bleeding or edema
Adverse effect
Are strange, unique, or unpredicted reactions. Ex blood in the urine a rare case for taking aspirin.
Idiosyncratic Response
Are reactions that are opposite of what would be expected.
Paradoxical Reaction
Is an antigen-antibody reaction. The body develops hives, rashes, itching, or swelling of the skin.
Allergic Response
Is a severe form of allergic reaction that is life threatening. The patient develops severe shortness of breath, may stop breathing, or may have cardiac collapse.
Anaphylactic Response
When two drugs are given together, the combined effect of the drugs is
equal to that of the single more active component of the mixture or to the
sum of the effects of the individual drugs.
Additive Effect
Effect takes place when one drug interferes with the action of another
drug
Antagonistic effect
Takes place when one drug replaces another at the drug receptor site,
increasing the effect of the first drug.
Displacement
Occurs when two drugs mixed together in a syringe produce a chemical reaction, so they cannot be given.
Incompatibility
Occurs when one drug promotes the rapid excretion of another, thus
reducing its activity.
Interference
Toxic effects or toxicity is identified by __________________.
monitoring the plasma (serum) therapeutic range of the drug
When the drug level exceeds the therapeutic range, toxic effects are
likely to occur from overdosing or drug accumulation. True or False?
True
the scientific discipline studying how the effect of a drug action varies from a predicted drug response because of genetic factors or hereditary influence
Pharmacogenetics
Because people have different genetic makeup, they do not always respond identically to a drug dosage or planned drug therapy. True or False?
True
refers to a decreased responsiveness over the course of therapy
Tolerance
refers to a rapid decrease in response to the drug
tachyphylaxis
Tachyphylaxis is an ____________.
“acute tolerance”
Drug categories that can cause tachyphylaxis include:
narcotics, barbiturates, laxatives, and psychotropic agents
A ___________ is a psychological benefit from a compound that may
not have the chemical structure of a drug effect.
placebo effect
Determinants that affect drug therapy
Clinical Factors
Administration
Pharmacokinetics
Pharmacodynamics
The Drug Approval Process
Drug discovery and development
Preclinical research and development
(IND Submitted)
Clinical trial
(NDA Submitted)
FDA reviews NDA
(FDA Approval)
Manufacturing
Through ____________, the public is protected from drugs that are impure, toxic, ineffective, or not tested before public sale.
federal legislation
What is the primary purpose of the federal legislation?
The primary purpose of the legislation is to ensure safety.
Nurses are responsible for knowing their state’s law and administrative code. True or False?
True
Nurses who administer a drug without a licensed health care provider’s order are in violation of the nurse practice act and can have their licenses revoked. True or False?
True
Negligence; wrong drug or drug dose that results in the patient’s death
Misfeasance
Omission; omitting a drug dose that results in the patient’s death
Nonfeasance
Giving the correct drug but by the wrong route that results in the patient’s death