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Drug Effects

Health differences: Excelsior College Nursing Theory Exam Study guide.
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Therapeutic effect
desired effect, the action for which the drug is given.
Adverse effect
a harmful unintended reaction of a drug.
Toxic effect:
a serious adverse effect that occurs when the plasma concentration of the drug reaches a dangerous, life threatening level.
Cumulative action
the increased activity demonstrated by a drug when repeated doses accumulate in the body and exert a greater biologic effect than the initial dose.
Drug Dependence
the physical or psychological reliance on a chemical agent resulting from continued use, abuse, addiction.
Hypersensitivity reaction
an abnormal, excessive response to a drug.
Idiosyncratic response
a person's unique sensitivity to a drug that is an unpredictable, highly individualized response.
Paradoxical reaction
a response to a drug that contrasts sharply with the usual, expected response.
Synergistic Effect
When two or more drugs are given together, one drug potentiates the other drug. Combined or concurrent action of the two drugs can increase therapeutic or adverse effects of either drug.
Tolerance:
the ability to endure ordinarily injurious amounts of a drug or the lowering of the effect obtained from an established dose that requires raising the dose to a possibly toxic level to maintain the same effect.
Drug allergy
a hypersensitive response to an allergen to which the individual has been exposed and has developed antibodies: usually occurs when drugs contain protein sources or combine with body protein to induce an allergen-antibody reaction.
Anaphylaxis
Life threatening episode of bronchial constriction and edema that obstructs the airway and causes generalized vasodilation that depletes circulating blood volume, when an allergen is administered to a person having antibodies produced by prior use of a drug.
Urticaria
generalized pruritic skin eruptions or giant hives.
Angioedema
fluid accumulation is periorbital, oral, respiratory tissues.
Delayed reaction allergies
rash and fever occurring during drug therapy.
Antagonistic drug effect
When 2 drugs have the opposite effects are administered together. each drug will cancel the affect of the other.
Individual factors influencing dosage and response
Age, Weight, sex, height, physiologic status, genetic and environmental factors.
Therapeutic Index (TI)
is used as a guide to the safe dosage range, but individual factors must be considered.
Concentration and duration of a drug action are affected by.
1.Characteristics of the drug and the rate of absorption, distribution, biotransformation (metabolism), and excretion.
2. Drug affinity for particular tissues.
Membrane barriers
Is a factor that influences a dosage or response; Placental, or blood-brain may block or selectively pass the drug from circulating fluids in protected areas of the body.
Potentiation
intensified action occurring when 2 drugs are administered concurrently that is greater than when either drug us administered alone.
Peak drug level
is the highest plasma concentration of drug at a specific time. It indicates the rate of absorption. A sample should be drawn at the proposed time according to the route of administration.
Trough drug level
is the lowest plasma concentration of a drug, it measures the rate at which the drug is eliminated. their drawn immediately before the next dose of drug is given, regardless of route of administration of the drug.
Low therapeutic index
have a narrow margin of safety. dosage may have to be adjusted and plasma serum drug levels need to be monitored because of small safety range between ED and LD.
high therapeutic index
have a wide margin of safety and less danger of producing toxic effects. Plasma serum levels do not have to be monitored routinely for these drugs.
Therapeutic window
of a drug concentration in plasma should be between minimum effective concentration in the plasma for obtaining desired drug action and minimum toxic effect.
Side effects
are physiologic effects not related to desired drug effects, can be either desirable or undesirable effects.
Loading dose
when an immediate drug response is desirable, a large initial dose is ordered.
Pharmacokinetic phase
refers to drug movement; ADME (absorption, distribution, metabolism, excretion)
Pharmacodynamics phase
refers to the action or effects of the drugs in the body.one important aspect is knowing the drugs onset, peak, and duration of action.
Drug binding sites
Are primarily on proteins, glycoproteins, proteolipids, and at enzymes.
Absorption
is the movement of drug particles from the GI tract to body fluids by passive absorption, active absorption, or pinocytosis. most drugs are absorbed thru the small intestine, and extensive mucosal microvilli.
Absorption of Insulin and growth hormones (protein based drugs)
are destroyed by digestive enzymes in the small intestine
Passive absorption
is mostly by diffusion, does not require any energy to move across the cell membrane.
Active absorption
require a protein carrier to move against a concentration gradient and energy is required.
Pinocytosis
is when a cell engulfs the drug and carries it across the membrane.
Lipid soluble drugs and non ionized drugs
are absorbed faster than water soluble drugs and ionized drugs.
First pass effect or hepatic first pass
is when a drug passes through the liver first