Pharmacologic Principles Flashcards
adverse drug event
any undesirable occurrence related to administering or failing to administer a prescribed medication
additive effects
drug interactions in which the effect of combination of two or more drugs with similar actions is equivalent to the sum of the individual effects if the same drugs given alone (e.g. 1 + 1 = 2 [compare with synergistic effects])
adverse drug reaction
any unexpected, unintended, undesired, or excessive response to a medication given at therapeutic dosages (as opposed to overdose)
adverse effects
a general term for any undesirable effects that are a direct response to one or more drugs
agonist
a drug that binds to and stimulates the activity of one or more receptors in the body
allergic reaction
an immunologic hypersensitivity reaction resulting from the unusual sensitivity of a patient to a particular medication; a type of adverse drug event
antagonist
a drug that binds to and inhibits the activity of one or more receptors in the body (antagonists are also called inhibitors)
antagonistic effects
drug interactions in which the effect of a combination of two or more drugs is less than the sum of the individual effects of the same drugs given alone (1 + 1 = <2); it is usually caused by an antagonising (blocking or reducing) effect of one drug on another
bioavailability
a measure of the extent of drug absorption for a given drug and route (from 0% to 100%)
biotransformation
one or more biochemical reactions involving a parent drug (biotransformation occurs mainly in the liver and produces a metabolite that is either inactive or active; also known as metabolism)
blood-brain barrier
the barrier system that restricts the passage of various chemicals and microscopic entities (e.g. bacteria, viruses) between the bloodstream and the central nervous system whilst still allowing the passage of essential substances (e.g. oxygen)
chemical name
the name that describes the chemical composition and molecular structure of a drug
contraindication
any condition, especially one related to a disease state or patient characteristic, including current or recent drug therapy, that renders a particular form of treatment improper or undesirable
cytochrome P-450
the general name for a large class of enzymes that play a significant role in drug metabolism and drug interactions
dependence
a state in which there is a compulsive or chronic need, as for a drug
dissolution
the process by which solid forms of drugs disintegrate in the gastrointestinal tract and become soluble before being absorbed into the circulation
drug
any chemical that affects the physiologic processes of a living organism
drug actions
the process involved in the interaction between a drug and body cells (e.g. the action of a drug on a receptor protein); also called mechanism of action
drug classification
a method of grouping drugs; may be based on structure or therapeutic use
drug effects
the physiologic reactions of the body to a drug; they can be therapeutic or toxic and describe how the body is affected as a whole by the drug; the terms onset, peak and duration are used to describe drug effects (most often referring to therapeutic effects)
drug-induced teratogenesis
the development of congenital anomalies or defects in the developing fetus caused by the toxic effects of drugs
drug interaction
alternation in the pharmacologic or pharmacokinetic activity of a given drug caused by the presence of one or more additional drugs; it is usually related to effects on the enzymes required for metabolism of the involved drugs
duration of action
the length of time the concentration of a drug in the blood or tissues is sufficient to elicit a response
enzymes
protein molecules that catalyse one or more of a variety of biochemical reactions, including those related to the body’s physiologic processes as well as those related to metabolism
first-pass effect
the initial metabolism in the liver of a drug absorbed from the gastrointestinal tract before the drug reaches systemic circulation through the bloodstream
generic name
the name given to a drug by ___; also called the nonproprietary name
the generic name is much shorter and simpler than chemical name and is not protected by trademark
glucose-6-phosphate dehydrogenase (G6PD) deficiency
a hereditary condition in which red blood cells break down when the body is exposed to certain drugs
half-life
in pharmacokinetics, the time required for half of an administered dose of drug to be eliminated by the body, or the time it takes for the blood level of a drug to be reduced by 50% (also called elimination half-life)
idiosyncratic reaction
an abnormal and unexpected response to a medication, other than an allergic reaction, that is peculiar to an individual patient
incompatibility
the characteristic that causes two parenteral drugs or solutions to undergo a reaction when mixed or given together that results in the chemical deterioration of at least one of the drugs
intraarterial
within an artery (e.g. intraarterial injection)
intraarticular
within a joint (e.g. intraarticular injection)
intrathecal
within a sheath (e.g. the theca of the spinal cord, as in an intrathecal injection into the subarachnoid space)
medication error
any preventable adverse drug event involving inappropriate medication use by a patient or health care professional; it may or may not cause patient harm
medication use process
the prescribing, dispensing, and administering of medications, and the monitoring of their effects
metabolite
a chemical form of a drug that is the product of one or biochemical (metabolic) reactions involving the parent drug
active metabolites are those that have pharmacologic activity of their own, even if the parent drug is inactive
inactive metabolites lack pharmacologic activity and are simply drug waste products awaiting excretion from the body (e.g. via the urinary, gastrointestinal, or respiratory tract)
onset of action
the time required for a drug to elicit a therapeutic response after dosing
parent drug
the chemical form of a drug that is administered before it is metabolised by the body’s biochemical reactions into its active or inactive metabolites
a parent drug that is not pharmacologically active itself is called a prodrug; a prodrug is then metabolised to pharmacologically active metabolites
peak effect
the time required for a drug to reach its maximum therapeutic response in the body
peak level
the maximum concentration of a drug in the body after administration, usually measured in a blood sample for therapeutic drug monitoring
pharmaceutics
the science of preparing and dispensing drugs, including dosage form design
pharmacodynamics
the study of the biochemical and physiological properties of drugs and their pharmacologic interactions with body receptors
pharmacoeconomics
the study of economic factors impacting the cost of drug therapy
pharmacogenetics
the study of the influence of genetic factors on drug response, including the nature of genetic aberrations that result in the absence, overabundance, or insufficiency of drug-metabolising enzymes
pharmacognosy
the study of drugs that are obtained from natural plant and animal sources
pharmacokinetics
the study of what happens to a drug from the time it is put into the body until the parent drug and all metabolites have left the body
pharmacokinetics represent the drug absorption into, distribution and metabolism within, and excretion from the body
pharmacology
the broadest term for the study or science of drugs
pharmacotherapeutics
the treatment of pathologic conditions through the use of drugs
prodrug
an inactive drug dosage form that is converted to an active metabolite by various biochemical reactions once it is inside the body
receptor
a molecular structure within or on the outer surface of a cell; receptors bind to specific substances (e.g. drug molecules ), and one or more corresponding cellular effects (drug actions) occurs as a result of this drug-receptor interaction
steady state
the physiologic state in which the amount of drug removed via elimination is equal to the amount of drug absorbed with each dose
substrates
substances (e.g. drugs or natural biochemicals in the body) on which an enzymes acts
synergistic effects
drug interactions in which the effect of a combination of two or more drugs with similar actions is greater than the sum if the individual effects of the same drugs given alone (e.g. 1 + 1 is > 2 [compare with additive effects])
therapeutic drug monitoring
the process of measuring drug levels to identify a patient’s drug exposure and to allow adjustment of dosages with goals of maximising therapeutic effects and minimising toxicity
therapeutic effect
the desired or intended effect of a particular medication
therapeutic index
the ratio between the toxic and therapeutic concentrations of a drug
tolerance
reduced response to a drug after prolonged use
toxic
the quality of being poisonous (i.e. injurious to health or dangerous to life)
toxicity
the conditions of producing adverse bodily effects due to poisonous qualities
toxicology
the study of poisons, including toxic drug effects, and applicable treatments
trade name
the commercial name given to a drug product by its manufacturer; also called the proprietary name
trough level
the lowest concentration of drug reached in the body after it falls from it’s peak level, usually measured in a blood sample for therapeutic drug monitoring
An elderly woman took a prescription medicine to help her to sleep; however, she felt restless all night and did not sleep at all. The nurse recognises that this woman has experienced which type of reaction or effect?
A. allergic reaction
B. idiosyncratic reaction
C. mutagenic effect
D. synergistic effect
B. idiosyncratic reaction
While caring for a patient with cirrhosis or hepatitis, the nurse knows that abnormalities in which phase of pharmacokinetics may occur?
A. absorption
B. distribution
C. metabolism
D. excretion
C. metabolism
A patient who has advanced cancer is receiving opioid medications around the clock to “keep him comfortable” as he beats the end of his life. Which term best describes this type of therapy?
A. palliative therapy
B. maintenance therapy
C. supportive therapy
D. supplemental therapy
A. palliative care
The nurse is giving medications to a patient in heart failure. The intravenous route is chosen instead of the intramuscular route. The nurse knows that the factor that most influences the decision about which route to use is the patients’s:
A. altered biliary function
B. increased glomerular filtration
C. reduced liver metabolism
D. diminished circulation
D. diminished circulation
A patient has just received a prescription for an enteric-coated stool softener. When teaching the patient, the nurse should include which statement?
A. “take the tablet with 2 to 3 ounces of orange juice”
B. “avoid taking all other medications with any enteric-coated tablets”
C. “crush the tablet before swallowing if you have problems with swallowing”
D. “be sure to swallow the tablet whole without chewing it”
D. “be sure to swallow the tablet whole without chewing it”
Each statement describes a phase of pharmacokinetics. Put the statements in order, with 1 indicating the phase that occurs first and 4 indicating the phase that occurs last.
A. enzymes in the liver transform the drug into an inactive metabolite
B. drug metabolites are secreted through passive glomerular filtration into the renal tubules
C. a drug that binds to the plasma protein albumin and circulates through the body
D. a drug moves from the intestinal lumen into the mesenteric blood system
A. 3
B. 4
C. 2
D. 1
A drug that delivers 500 mg has a half-life of 4 hours. How many milligrams of drug remain in the body after 1 half-life?
7.250 mg
pharmaceutical phase
disintegration of dosage form; dissolution of drug in body
pharmacokinetic phase
absorption, distribution, metabolism, excretion
pharmacodynamic phase
drug-receptor interaction
drug absorption of various oral preparations from fastest to slowest
oral disintegration, buccal tablets, and oral soluble wafers liquids, elixirs, and syrups suspension solutions powders capsules tablets coated tablets enteric-coated tablets
dosage forms: enteral
tablets, capsules, oral soluble wafers, pills, timed-released capsules, times-release tablets, elixirs, suspensions, syrups, emulsions, solutions, lozenges or troches, rectal suppositories, sublingual or buccal tablets
dosage forms: parenteral
injectable forms, solutions, suspensions, emulsions, powders for reconstitution
dosage forms: topical
aerosols, ointments, creams, pastes, powders, solutions, foams, gels, transdermal patches, inhalers, rectal and vaginal suppositories
intravenous (IV) advantages
provides rapid onset (drug delivered immediately to bloodstream); allows more direct control of drug level in blood; gives option of larger fluid volume, therefore diluting irritating drugs; avoids first-pass metabolism
intravenous (IV) disadvantages
higher cost; inconvenience (e.g. not self-administered); irreversibility of drug action in most cases and inability to retrieve medication; risk of fluid overload; greater likelihood of infection; possibility of embolism
intravenous (IV) nursing considerations
continuous intravenous infusions require frequent monitoring to be sure that correct volume and amount are administered and that the drug reaches safe, therapeutic blood levels; intravenous drugs and solutions must be checked for compatibilities; intravenous sites are to be monitored for redness, swelling, heat, and drainage - all indicative of complications, such as thrombophlebitis; if intermittent intravenous infusions are used, clearing or flushing of the line with normal saline before and after is generally indicated to keep the intravenous site patent and minimise incompatibilities
intramuscular (IM); subcutaneous (SC) advantages
intramuscular injections are good for poorly soluble drugs, which are often given in “depot” preparation form and are then absorbed over a prolonged period; insets of action differ depending on route
intramuscular (IM); subcutaneous (SC) disadvantages
discomfort of injection; inconvenience; bruising; slower onset of action compared to intravenous, although quicker than oral in most situations
intramuscular (IM); subcutaneous (SC) nursing considerations
use landmarks to identify correct IM and SC sites
IM:
ventral gluteal muscle
1 1/2-inch needle
20- to 25-gauge needle (for aqueous solutions)
18- to 25-gauge needle (for viscous or oil-based solutions)
SC:
90-degree angle
1/2- to 5/8-inch needle
26- to 30-gauge needle
oral advantages
usually easier, more convenient, and less expensive; safer than injection, dosing more likely to be reversible in cases of accidental ingestion (e.g. through induction of emesis, administration of activated charcoal)
oral disadvantages
variable absorption; inactivation of some drugs by stomach acid and/or pH; problems with first-pass effect or pre-systemic metabolism; greater dependence of drug action on patient variables
oral nursing considerations
some medications are to be taken with or without food; taken with fluids; consider other medicines taken at the same time and concurrent use of dairy products or antacids; if given via nasogastric or gastrostomy tubes, placement in the stomach needs to be assessed and the patient’s head is to remain elevated; flushing the NGT with at least 30 to 60 mL of water before and after to maintain potency and prevent clogging
sublingual; buccal advantages
absorbed more rapidly from oral mucosa and leads to more rapid onset of action; avoids breakdown of drug by stomach acid; avoids first-pass metabolism because gastric absorption is bypassed
sublingual; buccal disadvantages
patients may swallow pill instead of keeping under tongue until dissolved; pills often smaller to handle
sublingual; buccal nursing considerations
sublingual route are to be placed under the tongue; once dissolved, the drug may be swallowed; buccal route are placed between cheek and gum; both forms are relatively no no-irritating; drug is usually without flavour and water-soluble
rectal advantages
provides relatively rapid absorption; good alternative when oral route not feasible; useful for local or systemic drug delivery; usually leads to mixed first-pass and non-first-pass metabolism
rectal disadvantages
possible discomfort and embarrassment to patient; often higher cost than oral route
rectal nursing considerations
absorption is erratic and unpredictable; safe alternative when nausea and vomiting prevents oral dosing; patient must be placed on left side so that the normal anatomy of the colon allows safe and effective insertion; suppositories are inserted using a gloved hand and water-soluble lubricant
topical advantages
delivers medication directly to affected area; decreases likelihood of systemic drug effects
topical disadvantages
sometimes awkward to self-administer (e.g. eyes drops); can be messy; usually higher cost than oral route
topical nursing considerations
maximal absorption is enhanced with skin that is clean and free of debris; application must be done carefully and per instructions; gloves help to minimise cross-contamination and prevent absorption of drug into the nurse’s own skin; if patient’s skin is not intact, use sterile technique
transdermal advantages
provides relatively constant rate of drug absorption; one patch can last 1 to 7 days, depending on drug; avoids first-pass metabolism
transdermal disadvantages
rate of absorption can be affected by excessive perspiration and body temperature; patch may peel off; cost is higher; used patches must be disposed off safely
transdermal nursing considerations
transdermal drugs should be placed on alternating sites and on a clean, non-hairy, non-irritated area, and only after the previously applied patch has been removed and that area cleansed and dried
inhalation advantages
provides rapid absorption; drug delivered directly to lung tissues where most of these drugs exert their actions
inhalation disadvantages
rate of absorption can be too rapid, increasing the risk of exaggerated drug effects; requires more patient education for self-administration; some patients may have difficulty with administration technique
inhalation nursing considerations
medications are to be used exactly as prescribed and with clean equipment; instructions need to be given to the patient regarding medications to be used as well as proper use, storage, and safe-keeping of inhalers, spacers, and nebulisers
first-pass routes
hepatic arterial; oral; portal venous; rectal (leads to both first-pass and non-first-pass effects)
non-first-pass routes
aural (instilled into the ear); buccal; inhaled; intraarterial; intramuscular; intranasal; intraocular; intravaginal; intravenous; subcutaneous; sublingual; transdermal
diseases that decrease drug metabolism
cardiovascular dysfunction; renal insufficiency
conditions that decrease drug metabolism
starvation; obstructive jaundice; genetic constitution
drugs that increase drug metabolism
barbiturates; rifampin (P-450 inducer); phenytoin (P-450 inducer)
drugs that decrease drug metabolism
ketaconazole (P-450 inhibitor)
drug-receptor interactions: agonist
drug binds to receptor; there is a response
drug-receptor interactions: partial agonist (agonist-antagonist)
drug binds to the receptor; the response is diminished compared with that elicited by an agonist
drug-receptor interactions: antagonist
drug binds to the receptor; there is no response; drug prevents binding of agonists
drug-receptor interactions: competitive antagonist
drug competes with the agonist for binding to the receptor; if it binds, there is no response
drug-receptor interactions: non-competitive antagonist
drug combines with different parts of the receptor and inactivates it; agonist then has no effect
pharmacotherapeutic types of therapies
acute; maintenance; supplemental (or replacement); palliative; supportive; prophylactic (or empiric)
common food and drug interactions: leafy green vegetables
warfarin (anticoagulant); decreased anticoagulant effect from warfarin
common food and drug interactions: dairy products
tetracycline, levofloxacin, ciprofloxacin, moxifloxacin (antibiotics); chemical binding of drug leading to decreased effect and treatment failures
common food and drug interactions: grapefruit juice
amiodarone (antidysrhythmic); buspirone (antianxiety); carbamazepine (antiseizure); cyclosporine, tacrolimus (immunosuppressants); felodipine, nifedipine, nimodipine, nisoldipine (calcium channel blocker); simvastatin, atorvastatin (anticholesterol); decreased metabolism of drugs and increased effects
common food and drug interactions: aged cheese & wine
monoamine oxidase inhibitors; hypertensive crisis
common poisons and their antidotes: acetaminophen
acetylcysteine
common poisons and their antidotes: organophosphates (e.g. insecticides)
atropine
common poisons and their antidotes: tricyclic antidepressants, quinidine
sodium bicarbonate
common poisons and their antidotes: calcium channel blockers
intravenous calcium
common poisons and their antidotes: iron salts
deferoxamine
common poisons and their antidotes: digoxin and other cardiac glycosides
digoxin antibodies
common poisons and their antidotes: ethylene (e.g. automotive antifreeze solution), methanol
ethanol (same as alcohol used for drinking), given intravenously
common poisons and their antidotes: benzodiazepines
flumazenil
common poisons and their antidotes: beta blockers
glucagon
common poisons and their antidotes: opiates, opioid drugs
naloxone
common poisons and their antidotes: carbon monoxide (by inhalation)
oxygen (at high concentration), known as bariatric therapy
