the study of drugs and their interactions with living systems
A chemical substance that is used to treat or prevent disease or relieve pain.
Local effects of medications
act mainly at the site of application
Systemic effects of medications
taken into the body, circulated via the bloodstream to sites of action, and eventually eliminated from the body
Name drug sources
Plants, animals, minerals, synthetic compounds
How are drugs classified?
According to their effects on particular body systems, their therapeutic uses, and their chemical characteristics.
What are drug prototypes?
Individual drugs that present a group of drugs
What is an example of a drug prototype?
Morphine represents analgesics
How many names can a drug have?
What are the names of a drug?
Generic name, trade name, and chemical name
What is the risk of using different drug names for the same medication?
It increases confusion and the risk of misuse of a drug
How can drugs be accessed?
By prescription or over the counter
Medicines that cannot be used without the written approval of a licensed physician
Over the counter drugs
Drugs available to consumers without a prescription. Also called nonprescription drugs
Comprehensive Drug Abuse Prevention and Control Act
Gives a level of control over high abuse medications
Controlled Substances Act
The federal law giving authority to the Drug Enforcement Administration to regulate the sale and use of drugs.
Categories of Controlled Substances
This type of drug has no accepted medical use in the United States.
Examples of schedule I drugs
heroie, marijuana, ecstasy
Schedule II drugs
a type of drug with medicinal uses that is highly addictive and only available with a prescription
Examples of schedule II drugs
oxycodone, fentanyl, morphine
Schedule III drugs
a type of drug with medicinal uses that is moderately to highly addictive and only available with a prescription
Examples of schedule III drugs
ketamine, testosterone, anabolic steroids
Schedule IV drugs
a type of drug with medicinal uses that is moderately addictive and only available with a prescription
Examples of schedule IV drugs
lorazepam, tramadol, diazepam
Schedule V drugs
a type of drug with medicinal uses that is not very addictive and only available with a prescription
Examples of schedule V drugs
Lomotil, Robitussin AC
Who is responsible for approving new drugs in the US?
A list of medications that are generally considered inappropriate when given to elderly people
What are some sources for drug information?
Textbooks, internet sites, drug reference books, and journals
sources that use factually verifiable observations and data to provide rigorous conclusions that will not collapse under scrutiny
The process by which drugs are absorbed, distributed within the body, metabolized, and excreted.
absorption, distribution, metabolism, excretion
Rights of Medication Administration
Right to education
Right to refuse
Where are drug metabolizing enzymes located?
Kidneys, liver, RBCs, plasma, lungs, GI mucosa
Enzyme induction causes
Increased action (higher dosage)
Enzyme inhibition causes
Decreased action (lower dosage)
Serum drug level
Lab measurement of the amount of a drug in the blood at a particular time
minimum effective concentration
amount of drug required to produce a therapeutic effect
level of drug that results in serious adverse effects
Toxic concentration is caused by
A single large dose, many small doses given too frequently, and slow metabolism
receptor theory of drug action
Most drugs exert their effects by chemically binding with receptor cells through
-Activation, inactivation, or alteration of intracellular enzymes
-Changes in the permeability of cell membranes to one or more ions
-Modification of the synthesis, release, or inactivation of neurohormones
drugs that increase the action of a neurotransmitter
drugs that block the function of a neurotransmitter
Nonreceptor drug examples
antacids, osmotic diuretics, anticancer drugs, metal chelating agents
Drugs that do not act on receptor sites
Have to bind to receptor sites to produce a reaction
How does dosage effect drug reaction?
Frequency, number of doses, and size of dosage
How does the route of administration effect drug reaction?
Influences absorption and distribution
Drug to diet interactions
When elements of ingested nutrients interact with a drug and this affects the disposition of the drug
Drug to drug interactions
when the effect of a medication is changed, enhanced, or diminished when taken with another drug, including herbal substances
Drug interactions in which the effect of a combination of two or more drugs with similar actions is equivalent to the sum of the individual effects of the same drugs given alone.
combination of two drugs causes an effect that is greater than the sum of the individual effects of each drug alone
interference drug reaction
1 drug inhibits the metabolism or excretion of a 2nd drug, causes increased activity of the 2nd drug
Displacement drug reaction
displacement of 1 drug by a 2nd, increasing activity of the 1st
the study of how genetic inheritance affects the body's response to drugs
the study of how genetic variation affects an individual's response to drugs
Drug half life
the time required for the amount of drug in the body to decrease by 50%
t = 1/2
Equation for drug half life
What schedule of drugs is the least controlled?
Schedule V - least addictive
Which schedule of drugs is the most controlled?
Schedule I - most addictive
How do patients stretch their medications?
Patients will attempt to skip medications, cut a dosage in half, or use other family members' medications
The use of many different drugs concurrently in treating a patient, who often has several health problems.
Why might a patient try to stretch their drug supply?
They cannot afford the medication
Black Box Warning
A type of warning that appears in a drug's prescribing information and is required by the U.S. Food and Drug Administration (FDA) to alert prescribers of serious adverse events that have occurred with the given drug.
Examples of black box warning medications
the ratio between the toxic and therapeutic concentrations of a drug
QD/QOD (for daily/every other day)
U for unit
IU for international unit
MS/MSO4/MgSO4 (for morphine/magnesium sulfate)
Trailing zeros (e.g. 2.0 mg) following whole numbers
Naked decimal points (e.g. .5 mg) preceding doses less than zero
Available on ISMP or JACHO website
measurement of the diameter of a needle (lumen)
A larger needle has a
A smaller needle has a
Needle size depends on
patient size and weight, route of administration, and blood viscosity
What can affect drug absorption?
Blood flow, pain, stress, hunger, fasting, food, pH, dosage form and route of administration
Which oral dosage form of medication is faster in its absorption?
Solutions or liquid are absorbed faster than tablets.
How are dosages determined for pediatric patients?
Peds doses are milligram per kilogram based upon the patient's weight
What does it mean if a drug is protein bound?
Drugs that are protein bound cannot be distrusted through the body, only free drugs can cause action
Absorption changes in older adults
Lower acidity in stomach, decreased blood flow in intestines; not clinically significant
Distribution changes in older adults
Body water and lean body mass decreases, body fat % increases and causes high protein binding; lowers effectiveness of drug
Metabolism changes in older adults
Decline in metabolic capacity, decreased liver mass and hepatic blood flow
Excretion changes in older adults
Decreased renal blood flow, GFR is established
Examples of authoritative sources
American hospital formulary service
What patient age range is more susceptible to toxic concentration due to incorrect medication dosage?
What needs to be included on an Rx?
Patient name, name of medication (brand or generic), dosage, route, and frequency of administration, date, time, and signature or prescriber
What is the preferred method of ordering medication?
Typed into a computer
What must nurses know before giving a new drug?
Side effects, target patient age, preferred method of administration, and main use (for which ailment)