2. General Pharmacologic Principles and Special Considerations Flashcards
Sources of Drugs
- Plant
- Mineral
- Animal
- Synthetic
any chemical substance taken into the body for the purpose of affecting body function is referred to as a
drug
were the primary source of drugs used on the human body
Plants
_____ from the earth and ____ also found their way into human use as drugs
Minerals,
soil
Substances lacking in the human body can be replaced with similar substances from the glands, organs and tissues of ____
animals
evolved with human skills in laboratories and advanced understanding of chemistry
synthetic sources
this method is probably the most actively pursued source of drugs by major companies today
Synthetic
made from pork
Porcine
came from cow
Bovine
drug with a natural source but made with modifications in a laboratory
Semi-synthetic
movement of drugs through the body
Pharmacokinetics
what the body do to the drug
Pharmacokinetics
body’s biological response to drugs
Pharmacodynamics
what the drug do to the body
Pharmacodynamics
Pharmacokinetics
The four drug processes:
ADME
- Absorption
- Distribution
- Metabolism
- Excretion
getting into the bloodstream
Absorption
moving from the bloodstream into the tissues and fluids of the body
Distribution
physical and chemical alterations that a substance undergoes in the body
Metabolism
eliminating waste products of drug metabolism
Excretion
Absorption primary site of process
Mucosa of the stomach, mouth, small intestine, or rectum; blood vessels in the muscles or subcutaneous tissues; or dermal layers
Conditions that may hamper absorption
Incorrect administration may destroy the drug before it reaches the bloodstream or its site of action (e.g., giving certain antibiotics after meals instead of on an empty stomach
Distribution primary site of process
Circulatory system, through capillaries and across cell membranes
Conditions that may hamper distribution
poor circulation (impaired flow of blood) may prevent drug from reaching tissues
Metabolism primary site of process
Liver
Conditions that may hamper metabolism
Hepatitis, cirrhosis of liver, or damaged liver may prevent adequate breakdown of drug, thus causing a buildup of unmetabolized drug
Excretion primary site of process
kidneys, sweat glands, lungs, or intestines
Conditions that may hamper excretion
Renal damage or kidney failure may prevent passage or drug waste products, thereby causing an accumulation of the drug in the body
reaches widespread areas of the body
Systemic effect
Example:
acetaminophen [Tylenol] suppository, although given rectally, has the ability to be absorbed and distributed throughout the body to cause a general reduction in fever and pain
Systemic effect
is limited to the area of the body where it is administered
Local effect
Example:
dibucaine ointment [Nupercainal], applied rectally, affects only the rectal mucosa to reduce hemorrhoidal pain
Local effect
cellular changes
drug actions
physiological changes
drug effect
The site of absorption of drug varies according to the following physical properties of each drug:
- pH
- Lipid (fat) solubility
- Presence or absence of food in the stomach
drugs of a slightly acidic nature are absorbed well through the ______
stomach mucosa
drugs of an alkaline pH are not absorbed well through the stomach, but are readily absorbed in the alkaline environment of the ______
small intestine
oral medications for infants (syrup and solutions) may not be absorbed well after ____
infant feedings
substances high in lipid solubility are quickly and easily absorbed through the
mucosa of the stomach
Alcohol and substances containing alcohol are soluble in lipids. They are rapidly absorbed through the
gastrointestinal (GI) tract
Substances low in lipid are not absorbed well through the ______ and are absorbed best when given by a means other than the GI tract
stomach or intestinal mucosa
it is not lipid soluble but taken orally
neomycin drug
food in the stomach tends to slow absorption due to a ____ emptying of the stomach
slower
If a fast drug is desired, an _____ will facilitate quicker absorption
empty stomach
term when drug is transformed in the liver
biotransformation
is an increased effect of a drug demonstrated when repeated doses accumulate in the body.
cumulative effect
refers to a condition that results from exposure to either a poison or a dangerous amount of a drug that is normally safe when given in a smaller amount
Toxicity
Patient-related variables affecting
drug effects
Patient Parameters
Patient Parameters
- Age
- Weight
- Sex / Gender
- Psychological State
metabolism and excretion are slower in the _____, therefore attention must be paid to possible cumulative effects
elderly
they have a lower threshold of response and react more rapidly and sometimes in unexpected ways; therefore, frequent assessment is imperatice
children
generally, the bigger the person, the ____ the dose should be
greater
is an inactive substance that resembles a medication, although no drug is present
placebo
the action of two drugs working together in which one helps other simultaneously for an effect that neither could produce alone
Synergism
drugs that work together are said to be
synergistic
the action of two drugs in which one prolongs or multiplies the effect of the other
Potentiation
the opposing action of two drugs in which one decreases or cancels out the effect of the other
Antagonism
Response of drugs used in
combinations
Drug Interactions
Drug Interactions
- Synergism
- Potentiation
- Antagonism
Dosage
- Minimum
- Maximum
- Loading
- Maintenance
- Toxic
- Lethal
- Therapeutic
smallest amount of a drug that will produce a therapeutic effect
Minimum dose
largest amount of a drug that will produce a desired effect without producing symptoms of toxicity
Maximum dose
initial high dose (often maximum dose) used to quickly elevate the level of the drug in the blood (often followed by a series of lower maintenance doses)
Loading dose
dose required to keep the drug blood level at a steady state in order to maintain the desired effect
Maintenance dose
amount of a drug that will produce harmful side effects or symptoms of poisoning
Toxic dose
dose that causes death
Lethal dose
dose that is customarily given (average adult dose based on body weight of 150 lb); adjusted according to variations from the norm
Therapeutic dose
How do drugs travel?
Route of Administration
Route of Administration
- GI tract routes
- Parenteral routes
GI tract routes
- Oral (PO)
- Nasogastric tube (NG)
- Rectal (R)
Parenteral routes
- Sublingual (SL) or buccal
- Injection routes
- Topical
- Inhalation
Injection routes
- Intravenous (IV)
- Intramuscular (IM)
- Subcutaneous (SC)
- Intradermal (ID)
- Intracardiac, Intraspinal, Intracapsular
Topical
- Dermal (D)
- Mucosal
is the easiest, but the effects are slower because of the time required for disintegration of drugs in the alimentary canal before absorption
Oral route
is the fastest: drugs enter the bloodstream immediately and are administered by a physician, registered nurse or paramedic
Intravenous route
are less common and are administered by the physician
Intracardiac, Intraspinal, Intracapsular
is the best route for treatment of emergencies because of the speed of action
Intravenous
Unexpected response to drugs
Adverse Drug Effects
Adverse Drug Effects
- Teratogenic
- Idiosyncratic/Idiosyncrasy
- Tolerance
- Dependence
- Hypersensitivity
- Anaphylaxis
effect from maternal drug administration that causes the development of physical defects in a fetus
Teratogenic effect
unique, unusual response to a drug
Idiosyncrasy
decreased response to a drug that develops after repeated doses are given
Tolerance
acquired need for a drug that may produce psychological and/or physical symptoms of withdrawal when the drug is discontinued
Dependence
involves only a psychological craving, no physical symptoms of withdrawal other than anxiety
Psychological dependence
exists when cells actually have a need for the drug, symptoms of withdrawal include retching, nausea, pain, tremors, and sweating
Physical dependence
immune response (allergy) to a drug may be of varying degrees
Hypersensitivity
nausea, vomiting and diarrhea are __ considered signs of allergies
not
severe, possibly fatal, allergic response
Anaphylactic reaction
hives
urticaria
reddened, warm skin
hyperemia
is a cardiac drug that must be given cautiously because of its potential for causing a cumulative effect.
Digoxin
if Digoxin accumulates, the heart rate may slow to a _______
dangerously low level
