Principles Flashcards
Definition of drug
Any chemical that affects the physiologic processes of a living organism
What is Pharmacology
The study or science of drugs.”
(What do these chemicals-we-call-drugs do to us and what to we do to these chemicals-we-call-drugs?)
Three basic areas of pharmacology
Pharmaceutics (how dosage forms influence pharmacokinetics and pharmacodynamics)
Pharmacokinetics (what the body does to the drug)
Pharmacodynamics (what the drug does to the body)
Objective of pharm
Pharmacotherapeutics
The more clinically focused arm of pharmacology is called Pharmacotherapeutics, the study of drug actions when implementing drug therapy on specific clinical indications to prevent and treat disease.
Toxicology
specific to pharmacology, seeks to study the adverse effects of drugs on living organisms
Drug classifications based on
Action (what is being treated) OR on the body’s physiology
Prototype drug
A model for a drug class
Is a well understood
Has a known mechanism of action (how a drug produces its effect in the body) and known adverse effects
Is used to represent and compare other drugs in same pharmacologic class
Will be useful for you to concentrate on drug class prototypes when you study … (given for each drug family in your text)
The representative of this drug class
How many kinds of names does a Drug have
Chemical Name
Generic Name
Trade Name
Chemical name describes
The drugs chemical composition and moelcular structure
Generic name
Describes the chemical substance or pharmacological property of the drug.
Trade name
Propietrary name
The drug has a registered trademark use of the name resricted by the druges patent owner (usually manufacturer)
Clues to pharm class
Generic names of durvs in same pharm class often have same suffix
Drugs in a pharm class have similar attributes such as
Indications
Mechanisms of action
Contraindications and precautions
Interactions
Adverse Reactions and side effects
If you know about one drug in a class, you will have some knowledge of other drugs in the class T or F
True
Drugs in a pharm class may differ
Dosages and potency
- First, second, third + gens of drugs
Time action profile
Availability
Time action profile matters for
Knowing WHEN med should work
Helps us look out for side effects
Knowing when next dose COULD occur
ACE inhibitors abt drug in market
Includes at least 10 individual drugs
All end in “-pril”
Commonly prescribed drugs
Newer drugs have greater potency and require smaller amounts of drug or less dosing frequency
Drug classification schemas
Their action on a symptom/sign/condition
Ie., Antihypertensives, Antiemetics, Anticoagulants
Their action on a body system
Ie., drugs that affect the CNS, the Respiratory, the GI, the Endocrine systems
Their chemical nature
Ie., benzodiazepines, dopaminergics, glycosides, nitrates/nitrites
Their chemical action within the body
Ie., alpha blockers, beta blockers, opiods, vasodilators, bronchodilators
Their prescription category or OTC availability
Their clinical considerations (administration concerns)
Generic drugs are generally _____________ but may differ in their bioavailability ( the ability of the drug to reach its target tissue and produce an effect).
cheaper
The greatest barrier to drugs reaching their target cells
Diffusion (Passive and Active transport)
4 Parts of pharmacokinetics
Absorption
Distribution
Metabolsim
Excretion
Absorption of dru
(the movement of a substance from its site of administration, across body membranes to circulating fluids
Onset of action is faster
IV bipasses absorption and results in an immediate
Problem with IV meds
Non reversible
Fastest route of absorption
Inhaled
What factors increase or decrease the absorption of a drug
Food (slows absorption)
Digestive motility
Blood Flow
Lipid soluble medications work better
In body and absorption (Crossing cell layer)
Water soluble meds
Are excreted better
Drug Ionization
ASA is nonionized in the acidic environment of the stomach allowing it to be absorbed and distributed in the blood stream.
As it enters the alkaline environment of the stomach it becomes ionized and, in this form, it is not as likely to be absorbed and distributed.
Basic drugs are absorbed and distributed beteer in an ________ environments
Alkaline
A drug given via the oral route may be extensively metabolized by the ____ before reaching the _______ (high first-pass effect) and its target organ
Liver: systemic circulation
The same drug (PO) that is given parentally, (eg IV) - bypasses the liver preventingt the first pass effect from taking place and more drug gets into the general circulation and reaches its target organ
Same for mucosal, topical etc
Grapefruit juice can significantly _____ the absorption of some drugs
Increase
High fat meals can ___ the absorption of oral medications
Slow
Tyramine and MAOIs can cause a _______
HTN Crisis
Drug distribution
The transport of a drug in the body by the bloodstream to its site of action.
What factors would affect the distribution of a drug?
What factors affect distribution
Solubility
Blood Flow
Tissue storage
Areas of rapid distribution
Highly vascularized, or sites wiath a large blood volume
Not all drug molecules molecules in plasma will reach their target cells as they become bound to plasma ______especially albumin to form drug-protein complexes.
protien
Drugs bound to proteins will circulate in plasma until they are released or displaced. (Not intended effect)
A drug can only be freely distributed to extravascular tissue if it is not bound to protein (Why)
(if it is bound to protein it is too large to pass through capillary walls) thus it is not available for distribution.
Warfarin is ______ bound to plasma proteins
99%
ASA taken with Warfarin does what
if taken concurrently will displace Warfarin from the proteins.
At risk for hemorrhage
What do you do to avoid hemmorrhage
Provide antidote
Special Barriers preventing/affecting distribution
BBB
Fetal-Placental Barrier
Drug Metabolism (Biotransformation)
The biologic transformation of a drug so that it may be excreted more readily .
This often changes the drug from lipid soluble (easily absorbed and distributed) to a more water soluble compound, (which will more readily be excreted
Most drug metabolism occurs in the
Liver, where hepatic enzymes catalyze various biochemical reactions.
If liver DOESNT metabolize all drug, it cant all be excreted
Metabolis. of DRUGS also occurs in the
kidneys, intestinal mucosa, lungs, plasma and placenta.
Ability of liver to metabolize varies bc of
Genetics, liver disease, age
How to know liver function
Liver Function Lab Test
Results increase with lower function
Delayed drug metablism
accumulation of drug
Prolonged action of drug on target organ
Increased drug metabolism caises
Diminished drug affect
The rate at which drugs are excreted determine their ____. in the blood streamn
Conc
Most elimination
Kidneys
Lumgs
Saliva/sweat
Breast milk
CKD affect onf excretion
Prolonged drug action
Small to moderate changes in renal status can cause rapid changes in _______; therefore, what should the RN monitor?
serum drug levels
Lab results
Certain drugs may be excreted ________ if the pH of the filtrate changes
More quickly
Non-ionized and lipid soluble drugs cross renal tubular membranes _____-
Easily, and then return to circulation
Questions to ask when giving a drug
When, and how long will drug work
When do I first assess the pt for drug effect
How long do I need to moniter the pt
Onset
When med starts to work
PO: Usually 20-30 mins
Peak
When drug has maximum effect (highest conc of med in blood)
Duration
How long is drug in therapeutic range (How long is it working for)
Half Life
The time it takes for half of the original amount of a drug in the body to be conc in blood stream
Measure of rate at which drugs are removed from the body
Meds with a short half life are given MORE or LESS frequently
More
cSteady state serum level of drug
The amount of the drug eliminated is equal to the amount of the drug administered with each dose
Means that there are consistent levels of the drug in the body to achieve the desired therapeutic effect.
How many half lives ususlly to accomplish steady state
4-5 half lives
A drug with a long half life may take a _________ to achieve this state—sometimes a ‘______ ______’ is given.
Longer time; Loading dose
Loading dose
High dose given right away. Then, subsequently, a lower dose is given to keep it at a steady state
Efficacy
How efficient a drug is at creating a theraeptic effect
How to monitor for adverse affects
VS
Focus on relevant systems effected
Digoxin has a narrow thereapeutic index. What does that mean?
Monitor closely, assess for adverse effects
One of the most fundamental concepts in pharmacy
A higher dose would have a greater effect
If a dose is doubled, the response would have ______ the effect
Twice
Potency
The relative amount of drug needed to produce a response
A more potent drug will produce a therapeutic effect at a
Lower dose
Efficacy is the ______ amount of response that can be produced from a drug
Maximum
Receptor interaction
S molecule to which a medication binds to initiate its effect
Receptor interaction can be
Selective (binds with only one type of receptor)
Non selective (Binds with several types of receptors
Non-selective or selcetive have more adverse effects
Non seelective, bc they bind with receptors they shouldnt
Agonist
A drug can produce a response that mimics the effect of the endogenous regulatory molecule
Partial Agonist
a medication that produces a weaker or less effective response than an agonist
Antagonists
Block a receptor
3 types of antagonists
Competitive (Protamine sulfate, antidote to heparin - in it’s presence the body loses the anticoagulant properties of heparin)
Noncompetitive: Attach to molecule and block it
Functional: Don’t bind to receptors - Slow absorption, metabolism, making drug less effective
Do antagonists elicit a ersponse?
No
Nonspecific Interactions
Often oncological drugs (chemotherapy) and some antibiotics work by incorporating the drug into a natural metabolic pathway, causing a defective end product, such as an improperly formed cell wall or lack of energy product, resulting in cellular death
Once drug is at the site of action, it can
modify the tate (increase or decrease) at which the cell or tissue’s function
A drug cannot make a cell or tissue perform a function it was not designed to perform
T or F
True
What is your role in Preventing and Managing Drug Effects ?
Assess
Check MAR
Call Physician
Administer (3 Checks, ten rights)
Monitor for side effects and success
The nurses role in medication administration
Obtain a medical HX
Thoroughly assess the client and all diagnostic data.
Prevent medication Errors
Monitor carefully
Know the drugs.
Be prepared for the unusual
Question unusual orders
Teach clients about adverse effects
Our response to “I don’t take this med”
Always check
How to question unusual orders
Check the MAR
Check the MD orders
Tolerance
When you need more of the drug to produce the same desired effect (you are less sensitive)
What aspect of pharmacotherapy must be monitored
Therapeutic index
Drug concentration
Patient’s condition
Tolerance and dependence
Interactions
Side effects/adverse drug effects (potential lethal and most common)
Pharmacologic reactionsPharmacologic reactions (It works too good!
Pharmacologic reactions (It works too good!
Idiosyncratic reactions
(Particular to the patient, but not a true allergy or a pharmacologic rxn; eg., pt develops migraine with Percocet)
Allergic reactions
allergies—patient’s immune system decides to treat a drug as a dangerous character … and overreacts!)
Why would a carcinogenic drug be used?
Benefits outweigh the risks
Teratogens
Drugs that cause birth defect
Dose depednedt effect
The adverse effect’s intensity and occurrence are frequently related to the size of the dose
Expected adverse effects
well-known reactions that result in little or no change in patient management; i.e. side effects
What type of data is gathered in the assessment
Baseline data
Subjective data
Objective data
Adverse effects
Rights related to administration of medication
What is the health history composed of
Chief complain
Allergies
Past medical hx
Family Hx
What is drug history composed of
Drug hx
Health management
Reproductive hx
Personal and social hx
Plasma Proteins do what to drug distribution
High protein bound drug decreases amount of availble free drug
Distribution is decreased
High protein binding = high drug serum concentration
SOMETIMES the drug that is protein bound can be released into the blood stream extremely slowly
Low protein binding of drug
Increased distribution, high conc in interstial fluid
Major processes by which drugs are excreted
Kidneys (Most common)
(12 – bile (liver)
(13 – Exhalation (Lungs)
(14 – Feces (GI)
. Explain how enterohepatic recirculation might affect drug activity.
Increasing drug concentration and half life through recycling out of bile excretions that are remetabolized by the liver
Explain the applications of a drug’s plasma half-life (t1/2) to pharmacotherapy.
To do with the length of time the drug is present in circulation, matters for deciding when to give a subsequent dose
Subagaonist
Drug causing a submaximal afffect than would normally be seen
