Ch 4-8 Flashcards
Factors Affecting Drug Absorption
- The rate of drug dissolution
- The absorptive surface area
- Blood flow at the site of absorption
- Lipid solubility of the drug
- pH partitioning between the site of absorption and plasma
enteral drugs
Drugs administered by the oral route (per os, or PO)
parenteral
drugs administered outside the GI route
Capsule:
Drugs given by mouth pass through the stomach and are metabolized in the liver before reaching systemic circulation
Syringe:
Drugs administered by syringe immediately enter the circulatory system
Patch
Parenteral routes such as a transdermal patch release drugs directly into systemic circulation.
PO
oral or enteral
Bioavaliability
The percentage of a drug dose that actually reaches the systemic circulation chemically unchanged
IP
Intraparitoneal - up the ass
causes of low oral bioavalability
- The drug does not dissolve readily.
- Enzymes in the intestine may metabolize some of the drug before it is absorbed.
- The liver, metabolizes some of the drug on its first pass through the liver on the way to the systemic circulation.
advantages to IV route
- Has no membrane barriers; absorption is instantaneous and complete (100% bioavailability)
- Allows precise control of drug dose and duration
- Permits administration of poorly soluble drugs that must be dissolved in a large volume of fluid
- Allows irritating drugs to dilute rapidly in blood (e.g., cancer chemotherapeutic drugs would damage muscle if administered IM)
can enteric coated drugs be crushed and given through feeding tubes?
never because the protective coating will be lost. The crushed drug (now without the enteric coating) may be inactivated by the gastric acid or the drug may irritate the gastric mucosa.
can Sustained-release (XL, ER) medications be crushed and administered via feeding tubes?
Never. because crushing such formulations will cause a problem called dose dumping. Rather than a continuous delivery of medication to the site of absorption in the intestine, with dose dumping the entire dose is absorbed at once, and drug concentrations in the blood could reach toxic levels.
Can meds be desolved in hot water before being put in a feeding tube?
Never. Hot water may inactivate some drugs and precipitate others. The precipitate may accumulate on the side of the container or on the feeding tube itself and not be absorbed.
Disadvantages of IV administration of drugs
expensive, invasive, inconvenient
•Cannot remove the drug once it has been administered
•Risk for too high a drug concentration if injected too rapidly
•Risk for fluid volume overload
•Risk for infection
•Risk for embolism (from a clot, cellular debris, undissolved drug, or air)
•Risk for using wrong formulation (e.g., a concentrated solution designed for IM injection)
What if your IV solution looks dark?
Do not administer it! •IV solutions are dilute; IM solutions are concentrated and can be fatal if administered by IV.
Rate of absoorption after subcutaneous or IM injection is affected by…
- The ability of the drug to move through the fenestrations (gaps) in the capillary wall
- The solubility of the drug in water (plasma)
- Blood flow at the site of injection
disadvantages of IM and subcutaneous administration
- Bioavailability may be less than 100%.
- Non–water-soluble drugs may precipitate at the injection site.
- IM injections can cause local tissue injury and nerve damage if not administered properly.
- If a serious adverse reaction occurs (e.g., allergy), further absorption cannot be stopped.
Advantages of Transdermal adminstration
They provide for zero-order delivery, which means there is a constant plasma drug concentration with no peaks and troughs.
Peaks and Trophs
The highest and lowest drug levels in the plasma as measured over time
Characteristics needed in a drug for successful transdermal delivery
•A small molecular size
•Both hydrophilic and lipophilic properties
◦Lipophilicity is needed to penetrate the stratum corneum barrier.
◦Hydrophilicity is needed to diffuse into the extracellular fluid
The amount of drug delivered to the blood from transdermal patches
- The concentration of the drug in the patch or ointment
- The size of the application area
- The thinness of the stratum corneum and number of hair follicles (drug absorption from the chest > legs > arms > scalp > axillary > posterior ear > shin > palm)
when are Fluctuating drug levels in the blood (peaks and troughs) desirable?
antiinfectives, cancer chemotherapy
T or F: Drugs that can be absorbed through the skin are both lipid and water soluble.
True!
Are most PO drugs weak bases or weak acids, and where are they absorbed?
weak bases absorbed from the duodenum through the portal vein to the liver.
What is the range of rate at which the stomach can empty its contents (gastric emptying)
from a few minutes to 12 hours
Factors that decrease the rate of gastric emptying
- High-fat meal
- Heavy exercise after eating
- Lying on the left side after eating
- Drugs that inhibit the vagus nerve (e.g., anticholinergic drugs such as certain antihistamines, opioid pain relievers, antidepressants, and antipsychotics)
Factors that increase the rate of gastric emptying
•Taking PO medications with cold water on an empty stomach
•Lying on the right side (see figure)
Patients who receive tube feedings may have very rapid gastric emptying because of high osmolality. Some medications called prokinetic agents (e.g., metoclopramide [Reglan]) increase gastric emptying, so the drug may not completely dissolve in the stomach.
The oral bioavailability varies with the:
- type of formulation (e.g., syrup, tablet, time-release capsule)
- degree of first-pass metabolism in the small intestine and liver
these are called enteric-coated formulations.
Some formulations are manufactured with a special outer coating; Enteric-coated formulations are designed to avoid dissolution in the stomach and dissolve readily in the duodenum
Advantages of enteric-coated drugs
- Coatings protect the stomach from irritating drugs (e.g., erythromycin, bisacodyl [Dulcolax]).
- Coatings prevent gastric acid and pepsin from destroying the drug (e.g., pancreatic enzyme replacements).
Disadvantates of enteric-coated drugs
- Absorption varies with gastric emptying time (from minutes up to 12 hours).
- Coatings may not dissolve, in which case medication is not absorbed at all.
- Patients must avoid taking calcium supplements or antacids within 2 hours of taking enteric-coated drugs to avoid premature dissolution of coating
sustained release preparations
also called extended-release [ER] or XL) are designed to provide a constant (zero-order) rate of drug absorption over an extended period (12 to 24 hours).
Disadvantages of sustained release preparations
- Bioavailability varies more than with solid tablet counterparts.
- If a sustained-release formulation is crushed (and then, for instance, put down a feeding tube), the patient will absorb the entire dose at once, causing toxic drug levels in the blood. This is called dose dumping
Give examples of Some PO drugs undergo a degree of first-pass metabolism in the intestine
- Bacteria (called gut microflora) metabolize digoxin to a degree. Antiinfective therapy can kill these bacteria, causing a sudden increase in digoxin bioavailability (Figure A).
- Intestinal CYP3A4 enzymes metabolize a portion of certain antihypertensives (calcium channel blockers) and cholesterol-lowering agents (statins) before absorption
Why are some drugs not to be taken with grapefruit?
◦Grapefruit, limes, and citron (but not oranges) inhibit intestinal CYP3A4 causing more drug to be absorbed.
The treatment for poisoning can be influenced through manipulation of urine pH. The nurse correlates this with what?
Ion trapping: With manipulation of urinary pH, ion trapping draws toxic substances from the blood into the urine, thereby accelerating their removal from the body
The nurse correlates the faster absorption of highly lipid-soluble drugs with what
Rate of crossing cell membrane
In administering an intravenous medication by way of the antecubital vein over 1 minute, the nurse anticipates that the drug will reach the CNS in how many seconds?
Performing IV injections slowly has the advantage of reducing the risk of toxicity to the central nervous system (CNS). When a drug is injected into the antecubital vein of the arm, it takes about 15 seconds for it to reach the brain.
What laboratory results (which organ is depressed)would the nurse recognize as most significant when considering excretion of drugs?
Depressed renal function
What is the “First Pass” effect?
refers to the rapid inactivation of certain oral drugs as they pass through the liver. Drugs absorbed from the gastrointestinal tract are carried directly to the liver by way of the hepatic portal vein. Drugs that have a too-rapid first-pass effect may be completely inactivated and require administration by way of a different route.
Enteric-coated medis are designed to desolve where?
in the small intsetine
The most important protein for the binding of drugs
Albunin
The objective of drug dosing is to maintain ____ drug levels within the therapeutic range.
plasma
A drug that has only moderate intrinsic activiy
Partial Antagonist
A drug that activates receptors
Agonist
A drug that prevents receptor activation by endogenous regulatory molecules
Antagonist
Simple occupancy theory
the intensity of the response to a drug is proportional to the number of receptors occupied by that drug and that a maximal resonse will occur when all available receptors have been occupied.
Maximal efficacy
the largest effec a drug can produce; not always desirable to give it.
How do transcription factors differ from other receptors?
- found within the cell, not on the cell membrane; responses that activate these receptors are delayed
The distribution of a drug in the body is determined by:
- Blood flow to the tissues
- Capacity of the drug to move out of the blood
- Capacity of the drug to move into cells
Bioavalability
percentage of the dose that passes through the liver to the systemic circulation unchanged
Your patient is suffering from digoxin toxicity. He is seeing halos around lights and has cramps in his legs. He reports that he started taking an antibiotic 4 days ago for “walking pneumonia.” You suspect that
the antibiotic killed the intestinal bacteria that metabolize digoxin
The body’s compartments involved in drug distribution include:
- Interstitium (extracellular fluid) (e.g., low-molecular-weight, hydrophilic drugs)
- Total body water (extracellular and intracellular fluid) (e.g., low-molecular-weight, hydrophilic drugs)
- Plasma (e.g., drugs strongly bound to plasma proteins and drugs with a very high molecular weight)
- Adipose (fat) tissue (e.g., lipophilic drugs)
- Muscle tissue (e.g., drugs such as digoxin)
- Bone (e.g., drugs that bind to calcium)
The distribution of a drug in the body is determined by:
- Blood flow to the tissues
- Capacity of the drug to move out of the blood
- Capacity of the drug to move into cells
•Drugs that are distributed into breast milk or fetal tissues are those that are
◦Lipophilic
◦Nonionized
◦Small in molecular size
•Drugs that are not distributed into breast milk or fetal tissues are those that are:
◦Polar
◦Ionized
◦Large in molecular size
◦Protein bound
The volume of distribution (Vd)
the ratio of the total amount of drug in the body (D) to the plasma concentration of the drug (C): Vd = D/C
large Vd means that:
- Most of the drug is distributed in some body compartment (e.g., muscle, bone, fat)
- A smaller fraction of the drug is in the plasma
A small Vd means that:
- The drug is highly bound to plasma proteins
* The drug does not distribution widely into other compartments
There are two principal plasma proteins that bind drugs:
- Albumin (binds acidic drugs)
* Alpha-1-acidic glycoprotein (AAG) (binds alkaline drugs)
which conditions decrease plasma albumin and increase free drug levels
- Malnutrition (especially in the elderly)
- Liver disease
- Kidney disease
- Aging
- Trauma (especially burns)
Some conditions increase liver synthesis/release of AAG and decrease free drug levels
Aging
Trauma
and inflamed liver (HepA)
Sites of biotransformation
- Stomach (alcohol dehydrogenase)
- Intestine (CYP3A4 enzyme in the brush border and bacteria metabolize some drugs before absorption;)
- Liver (over 12 different enzyme families exist in the smooth endoplasmic reticulum and cytosol)
- Kidney (per gram, more metabolically active than liver, but only a few drugs are metabolized)
Endogenous Substrates
Made by the body: •Vitamin D hormone
•Cholesterol
•Steroid hormones
•Bilirubin
Exogenous Substrates
Foreign compounds: •Compounds in charcoal-broiled food
•Compounds in cigarette and marijuana smoke
•Caffeine
•Alcohol
•Toxic compounds in plants
•Drugs
site of first-pass mechanism for alcohol
Stomach
•Alcohol dehydrogenase
converts some alcohol to acetaldehyde, which is then further metabolized in the liver.
- Low-ER drugs have high oral bioavailability. (Less than 20% of a PO dose undergoes first-pass metabolism.)
- PO doses of low-ER drugs are similar to IV doses.
- Small changes in hepatic enzyme activity have little effect on the bioavailability of low-ER drugs.
Low-ER drugs
- High-ER drugs have low oral bioavailability (80%-97% of an oral dose is metabolized by the liver before reaching the systemic circulation).
- PO doses of high-ER drugs must be higher than IV doses to compensate for the extensive first-pass metabolism.
- Small changes in hepatic enzyme activity produce large changes in the bioavailability of high-ER drugs.
High-ER drugs
cytochrome P-450 enzymes (CYPs
complex system of enzyme families housed by smooth endoplasmic reticulum
T or F Drugs that are distributed into fat will have an increased Vd.
True
What happens if a drug with a small Vd is displaced from albumin by a second drug?
There will be no change in total plasma b/s Vd do not have much distribution to compartments outside of the blood. Displaced drug will remain in the blood. The amount of free drug in the plasma will increase, and the amount bound to plasma protein will decrease. The total plasma drug level will not change.
A large Vd means that
drug that is displaced from plasma proteins will move out of plasma and into tissues.
The three steps in the urinary excretion of drugs are:
- Glomerular filtration
- Passive tubular reabsorption
- Active tubular secretion
Glomerular Filtration
The hydrostatic pressure within capillaries in the glomeruli forces low-molecular-weight drugs and metabolites into the urine in the renal tubules. Large molecules and drugs bound to plasma proteins such as albumin are too large to undergo glomerular filtration.
passive tubular reabsorption
Lipid-soluble drugs that were filtered into the urine from the glomerular capillaries can move across the membranes of the tubule and efferent arteriole back into the blood.
what kind of Drugs and metabolites are water soluble ?
polar molecules and ions)
Biotransformation
Enzymatic changes made to the chemical structure of non-polar, lipophylic molecules so that they may be eliminated by the body
parent drug
initial drug administered; can be biotransformed to an active or inactive metabolite
Name some conjugates
glucuronic acid, glutothione,, acetate, sulphate, or an amino acid such as glycine
define conjugate
compounds added to molecules in Phase II metobolism ; have increased polarity and water solubility
Drug elimination occurs primarily
in the kidney and feces but also in the lungs.
Enterohepatic recycling
the deconjugation and reabsorption of parent drug and active metabolites secreted in the bile
ADME
drug absorption, distribution, metabolism, and excretion
Minimal effective concentration. MEC
There is a plasma drug concentration below which a therapeutic effect will not take place.
Toxic concentration.
If the plasma drug concentration goes too high, toxic side effects will occur.
Duration.
The length of time the plasma drug concentration is above the MEC
Therapeutic range.
The goal of pharmacotherapy is to keep the plasma drug concentration above the MEC and below the toxic concentration—Drugs with a narrow therapeutic range are more difficult to manage.
the ratio of the toxic concentration to the MEC
onset of action
How long it takes for the drug to get to a plasma level at which a therapeutic effect can occur
effected by the rate and extent of absorption
By the time five half-lives have elapsed, what percentavge of the drug will be removed from the body
97%
How many half-lives to rid the body of every drug molecule.
9 half lives
Vd/Cl). A large volume of distribution and/or a small clearance will cause the half-life to be large relative to drugs with a small volume of distribution, a large clearance, or both.
i didnt know how to make this into a question, so it’s a statement
Ashley G has taken oral phenytoin for 4 years to control her seizure disorder. She has just been hospitalized for anorexia nervosa. Her total phenytoin level is subtherapeutic at 4 mcg/mL. She continues to be free of seizures. What should be done?
Her free phenytoin level should be checked; it is probably in the therapeutic range.
A formulation of a PO drug that has a slow rate of absorption may not reach the MEC and therefore may not be clinically effective. T or F
True
characteristics of drugs with a narrow therapeutic range:
They are more likely to produce toxic effects when they are displaced from plasma proteins compared with displacement of drugs with a wide therapeutic range.
B. Different formulations are likely to have differences in bioavailability.
C. They may elicit different pharmacologic and toxic responses in different patients given the same dose over the same interval.
Why are loading doses used for some drugs?
To help drugs with long half-lives reach Css quickly. Css to be reached. Administration of a loading dose (equal to the total amount of drug in the body at steady state) shortens the time to the onset of therapeutic action.
The time it takes for the plasma drug concentration to decrease by 50%
drug half-life
•T1/2 is proportional to the volume of distribution (Vd). A person with more body fat will have a ______ Vd for drugs that are distributed into fat (e.g., diazepam [Valium]) and a longer T1/2.
large
•T1/2 is inversely proportional to the total body clearance (Cl) of the drug by the liver, kidney, or other route. A person with renal or hepatic impairment will have a _______ drug clearance and a longer T1/2.
slower
True or False
•T1/2 is a poor indicator of the rate of clearance of an oral drug. An older person could have a decreased renal clearance of digoxin and a decreased digoxin Vd (because of loss of muscle mass), and the T1/2 might not change.
True
True or False: •T1/2 is important for predicting how long it will take for a drug level to reach a plateau and how long it will take for drug levels to go below the MEC after the drug is stopped.
True
what does this symbol mean? (Css)
steady-state concentration level
what does this symbol mean? (Css)
steady-state concentration level
what is meant by “ dose-response relationships are monotonic “
response goes up as the dose is increased
three-phase illustration of the dose-response:
- Phase 1: Doses are too low to elicit a clinical response.
- Phase 2: The response is graded and appears linear on the semilogarithmic plot.
- Phase 3: Higher doses cannot elicit a large response (but can cause toxicity!).
Therapeutic efficacy
How effective a drug at a given dose at eliciting a desired response (e.g., lowering blood pressure)
T or F: Two drugs with very different molecular structures and mechanisms of action, given in very different doses, can have the same degree of therapeutic efficacy.
True
The maximal _____ is determined by inspecting the height of the dose-response curve and determining which dose produces the maximal response (typically where the dose-response curve begins to level off, at Phase 3).
efficacy
pharmacologic potency
the amount of drug (e.g., the number of milligrams) needed to elicit a response. If one drug is more potent than another, it means that the dose required to get the desired effect is smaller with one drug than with the other, not mean that the more potent drug is more therapeutically effective!
Two advantages of intramuscular administration:
- suitability for poorly soluble drugs and
- suitability for depot preparations
Two disadvantages of IM administration:
- inconvenience and pain
Chemically equivalent
Drug preparations that contain the same amount of the identical chemical compound (drug); 2 formulations of the same drug can be chemically equivalent but still differ in their bioavailabiity.
P50 system:
- hepatic microsomal enzyme system located in the liver, where most drug metabolism takes place.
2 concequences of induction of drug-metabolizing enzymes by a drug:
1) stimulate liver to produce more drug-metabolizing enzymes and increasing the drug’s rate of own metabolism and required more dosage to maintain therapeutic effects,
2) accelerate the metabolism of other drugs used concureently, necessitating an increase in their dosages
3 steps of Renal drug excretion:
1) glomerular filtration,
2) passive tubular reabsorption and
3) active tubular secretion
enterohepatic recirculation
- reabsorption of drugs into the portal blood from the intestine (via the bile); can substantially prolong presence of a drug in the body
MEC
“Miniumum effective concentration” - the plasma drug level below which therapeutic efects do not occur
Toxic concentration
- the plasma level at which toxic effects begin
Therapeutic range of a drug
- lies b/n the MEC and the toxic concentration
Plateau
- the steady state of a drug that is administered repeatedly - it gradually rises and then steadies out
3 techniques to reduce fluctuations in drug levels:
!) adminstering drugs by continuaous infusion
2) adminstering a depot preparation that releases slowly and steadily and
3) reducing both size of each dose and dosing interval to keep total daily dose constant
4 primary families of receptors:
cell membrane-embedded enzymes,
ligand-gated ion channels,
G protein-coupled receptor systems, and
transcription factors
Intrinsic activity
- the ability of a drug to activate a receptor upon binding; drugs with high intrinsic activity have high maximal efficacy
2 major classes of antagonists:
competitive (are reversible), noncompetitive (are irreversible)
desinsitization or refractory or down-regulation
- terms for when the receptors of a cell are coninually exposed to an agonist, making the cell less responsive
Hypersinsitive, supersensitive
-terms for the cell when exposed to continuous antagonistic action
ED50
- average effective dose required to produce a defined therapeutic response in 50% of the poplulation.
Therapeutic index:
- the LD50:ED50 ration, a measure of a drug’s safety; the higher therapeutic index, the safer the drug
Potentiative interaction
- when one drug intsnsifies the effects of another drug; can be beneficial or detrimental
4 basic mechanisms through which drugs interact:
1) direct chemical or physical interaction
2) pharmacokinetic interaction
3) pharmacodynamic interaction
4) combined toxicity
2 mechanisms by which one drug can alter distribution of another:
1) competition for protein binding, 2) alteration of the extracellular pH
Inducing agents
- drugs that stimulate the synthesis of CYP isozymes
order of OS abosorption
aqueous solutions syrups elixirs suspensions chewable tablets granules capsules compressed tablets enteric-coated tablets time-release capsules
Many people over age 65 who are concerned about Alzheimer’s disease begin to self-medicate with ibuprofen (Advil, Motrin) and gingko. This practice may:
A. Incorrect delay onset by several years through an antioxidant effect.
B. prevent the progression of the disease once it begins.
C. Correct cause an interaction with cardiac medicines.
D. improve blood flow to the brain and the reduce risk of dementia.
Teratogenic effect
- drug-induced birth defect
2 important types of organ-specific toxicity
1) injury to liver
2) altered cardiac function (evidenced by a prolonged QT interval on ECG)
QT interval drugs
- drugs that can prolong the QT interval on the ECG, thereby creating a risk of serious dysrhythmias
System erros that can cause medication errors:
prescribing, order communication, product labeling, packaging and nomenclature, compounding, dispensing, distribution, administration, education, monitoring, and use
3 most common types of fatal medication errors:
giving an overdoes, giving the wrong drug, and using the wrong route
3 most common causes of fatal medication erros are human factors:
human factors, communication mistakes and confusion caused by similarities in drug names
4 effective measures for reducing medication erros:
replacing handwritten med orders with a computerized system
having a clinical pharmacist accompany intensive care unit physicians on rounds
using copmuterized bar-code system
using medication reconciliation when patients undergo a transition in care
what happens when potassium levels are depressed?
- the ability of digoxin to induce sysssrhythmias is greatly increased
Metabolic tollerance
- tolerance that results from accelerated drug metabolism
Tachyphylaxis
- a form of tolerance that can be defined as areduction in drug responsibeness brought on by repeated dosing over a short period
Many people over age 65 who are concerned about Alzheimer’s disease begin to self-medicate with ibuprofen (Advil, Motrin) and gingko. This practice may:
A. Incorrect delay onset by several years through an antioxidant effect.
B. prevent the progression of the disease once it begins.
C. Correct cause an interaction with cardiac medicines.
D. improve blood flow to the brain and the reduce risk of dementia.
Teratogenic effect
- drug-induced birth defect
2 important types of organ-specific toxicity
1) injury to liver
2) altered cardiac function (evidenced by a prolonged QT interval on ECG)
QT interval drugs
- drugs that can prolong the QT interval on the ECG, thereby creating a risk of serious dysrhythmias
System erros that can cause medication errors:
prescribing, order communication, product labeling, packaging and nomenclature, compounding, dispensing, distribution, administration, education, monitoring, and use
3 most common types of fatal medication errors:
giving an overdoes, giving the wrong drug, and using the wrong route
3 most common causes of fatal medication erros are human factors:
human factors, communication mistakes and confusion caused by similarities in drug names
4 effective measures for reducing medication erros:
replacing handwritten med orders with a computerized system
having a clinical pharmacist accompany intensive care unit physicians on rounds
using copmuterized bar-code system
using medication reconciliation when patients undergo a transition in care
what happens when potassium levels are depressed?
- the ability of digoxin to induce sysssrhythmias is greatly increased
Metabolic tollerance
- tolerance that results from accelerated drug metabolism
Tachyphylaxis
- a form of tolerance that can be defined as areduction in drug responsibeness brought on by repeated dosing over a short period
Many people over age 65 who are concerned about Alzheimer’s disease begin to self-medicate with ibuprofen (Advil, Motrin) and gingko. This practice may:
A. Incorrect delay onset by several years through an antioxidant effect.
B. prevent the progression of the disease once it begins.
C. Correct cause an interaction with cardiac medicines.
D. improve blood flow to the brain and the reduce risk of dementia.
Teratogenic effect
- drug-induced birth defect
2 important types of organ-specific toxicity
1) injury to liver
2) altered cardiac function (evidenced by a prolonged QT interval on ECG)
QT interval drugs
- drugs that can prolong the QT interval on the ECG, thereby creating a risk of serious dysrhythmias
System erros that can cause medication errors:
prescribing, order communication, product labeling, packaging and nomenclature, compounding, dispensing, distribution, administration, education, monitoring, and use
3 most common types of fatal medication errors:
giving an overdoes, giving the wrong drug, and using the wrong route
3 most common causes of fatal medication erros are human factors:
human factors, communication mistakes and confusion caused by similarities in drug names
4 effective measures for reducing medication erros:
replacing handwritten med orders with a computerized system
having a clinical pharmacist accompany intensive care unit physicians on rounds
using copmuterized bar-code system
using medication reconciliation when patients undergo a transition in care
what happens when potassium levels are depressed?
- the ability of digoxin to induce sysssrhythmias is greatly increased
Metabolic tollerance
- tolerance that results from accelerated drug metabolism
Tachyphylaxis
- a form of tolerance that can be defined as areduction in drug responsibeness brought on by repeated dosing over a short period
Many people over age 65 who are concerned about Alzheimer’s disease begin to self-medicate with ibuprofen (Advil, Motrin) and gingko. This practice may:
A. Incorrect delay onset by several years through an antioxidant effect.
B. prevent the progression of the disease once it begins.
C. Correct cause an interaction with cardiac medicines.
D. improve blood flow to the brain and the reduce risk of dementia.
Teratogenic effect
- drug-induced birth defect
2 important types of organ-specific toxicity
1) injury to liver
2) altered cardiac function (evidenced by a prolonged QT interval on ECG)
QT interval drugs
- drugs that can prolong the QT interval on the ECG, thereby creating a risk of serious dysrhythmias
System erros that can cause medication errors:
prescribing, order communication, product labeling, packaging and nomenclature, compounding, dispensing, distribution, administration, education, monitoring, and use
3 most common types of fatal medication errors:
giving an overdoes, giving the wrong drug, and using the wrong route
3 most common causes of fatal medication erros are human factors:
human factors, communication mistakes and confusion caused by similarities in drug names
4 effective measures for reducing medication erros:
replacing handwritten med orders with a computerized system
having a clinical pharmacist accompany intensive care unit physicians on rounds
using copmuterized bar-code system
using medication reconciliation when patients undergo a transition in care
what happens when potassium levels are depressed?
- the ability of digoxin to induce sysssrhythmias is greatly increased
Metabolic tollerance
- tolerance that results from accelerated drug metabolism
Tachyphylaxis
- a form of tolerance that can be defined as areduction in drug responsibeness brought on by repeated dosing over a short period
