Ch. 2: Pharmacologic Principles Flashcards
Define:
Drug
Pharmacology
Drug: any chemical that affects the physiologic processes of a living organism
Pharmacology: study/science of drugs
Explain the patent life
The time after discovery of a drug for the founder to have full control/jurisdiction over it and the price
Price of drug is usually much higher during the patent life
After the patent life expires, the drug can be created in generic forms by other manufacturers, and the price usually drops
What drug name is always used by nurses?
Generic name (nonproprietary)
Not the trademark name
Define:
Pharmaceutics
Pharmacokinetics
Pharmacodynamics
Pharmacogenomics
Pharmaceutics: Different dosage forms have different properties/dissolution rates/effects on the body
Pharmacokinetics: What the body does to the drug- Absorption, Distribution, Metabolism, Excretion
Pharmacodynamics: What the drug does to the body
Pharmacogenomics: genetic factors/drug responses
Define:
Pharmacotherapeutics
Pharmacognosy
Pharmacoeconomics
Toxicology
Pharmacotherapeutics: Expected outcomes of drug therapy
Pharmacognosy: natural drug sources (plants/animals)
Pharmacoeconomics: factors influencing the cost of drug therapy
Toxicology: poisons/unwanted responses to drugs
List the different med forms in order of fastest dissolution to slowest
Oral disintegration, buccal tablets, oral soluble wafers
Liquids, elixers, syrups
Suspension solutions
Powders
Capsules
Tablets
Coated tablets
Enteric-coated tablets
Why do enteric-coated tablets take so long to be absorbed?
They are designed to break down in the alkaline environment of the small intestine
Explain:
Bioavailability
First-Pass Effect
Which form of med has 100% bioavailability?
Which form of med has a high first-pass effect?
Bioavailability: the extent of drug absorption (IV= 100%)
First-Pass Effect: Drugs taken through the enteral route must pass through the liver before reaching the bloodstream- much smaller amount reaches bloodstream due to liver metabolism into inactive metabolites
PO meds have a high first-pass effect
List the 4 First-Pass Routes
Hepatic Arterial
Oral
Portal Venous
Rectal (can be non-first-pass too)
Which 4 organs are drugs distributed to first?
Heart, Liver, Kidneys, Brain
What is required before a drug can be distributed outside of the blood vessel?
It must detach from a plasma protein
What happens when drugs compete for albumin binding sites?
More unbound drugs may be present in the bloodstream, leading to more interactions
What 4 forms can metabolism (biotransformation) change a drug into?
Inactive metabolite
More soluble compound
More potent active metabolite
Less active metabolite
Which cytochrome enzyme targets lipid-soluble drugs that are more difficult to eliminate and are responsible for the metabolism of most medications?
Cytochrome P-450 Enzymes
Explain lipophilic vs hydrophilic drugs
Which form is required for drug excretion?
Lipophilic: dissolves in fat/oil, crosses cell membrane easily and quickly
Hydrophilic: dissolves in water, needs help/time to cross cell membrane
Hydrophilic form is required for the drug to be excreted
Where are most drugs made more water-soluble?
Liver
What is biliary excretion?
Excretion through intestines
What is enterohepatic recirculation?
Fat-soluble drugs can be released into bile and can be taken up again into the bloodstream
What is the Half-Life?
After how many half-lives can a drug be considered effectively removed from the body?
The time required for half of a given drug to be removed from the body
5 half-lives
Explain Steady State
Physiologic state in which the amount of drug removed via elimination is equal to the amount of drug absorbed with each dose
Important for antibiotics
If the half life can range from 10-60 hours, how long will it take to effectively remove the drug from the body?
10x5=50 hours
60x5= 300 hours
can take 50-300 hours to remove
Explain:
Peak Level
Trough Level
Peak level: highest concentration in blood
Trough level: lowest concentration in blood (taken 30 mins before next dose)
Explain:
Onset of action
Peak Effect
Duration of Action
Onset of Action: time required for the drug to elicit a response- when it starts working
Peak Effect: time required for a drug to reach max therapeutic response- when it’s the strongest
Duration of Action: Length of time the drug concentration is sufficient to elicit a therapeutic response- how long it lasts
Explain therapeutic drug monitoring
What do you do is the trough is too high for the next dose?
Monitoring the peaks the troughs of meds to determine correct dosing
Trough too high= hold drug, notify provider
Define:
Therapeutic effect
Mechanisms of Action
-Drug-receptor relationship
-Enzymes
-Nonselective Interactions
Therapeutic Effect: Desired/intended effect
Mechanisms: how the drug does it
Drug-receptor relationship: Drug binds to cell receptor and produces a response
Enzymes: drug inhibits or enhances an enzyme’s action
Nonselective Interactions: Drug targets the cell membrane or a cellular process
Explain the following drug-receptor interactions:
Agonist
Partial Agonist
Antagonist
Competitive Antagonist
Noncompetitive Antagonist
Agonist: Drug binds to receptor- there is a response
Partial Agonist: Drug binds to receptor- diminished response
Antagonist: Drug binds to receptor: NO response, prevents binding of agonist
Competitive Antagonist: Drug competes with agonist for receptor binding, if it binds, there is no response
Noncompetitive Antagonist: Drug combines with different parts of the receptor and inactivates it, agonist then has no effect
Explain off-label prescriptions
Meds prescribed for a non-FDA approved indication (allowed)
Explain the following aspects of pharmacotherapeutics:
-Contraindications
-Acute Therapy
-Maintenance Therapy
-Supplemental Therapy
Contraindications: pt condition that makes a med use dangerous
Acute: Sustains life/treats disease- vasopressors, epi-pens
Maintenance: prevents progression of a disease or condition- antihypertentives, birth control pills
Supplemental: supplies body w/ a substance needed for normal functions: insulin
Explain the following aspects of pharmacotherapeutics:
-Palliative Therapy
-Supportive Therapy
-Prophylactic Therapy
-Empiric Therapy
Palliative: relief of symptoms to improve quality of life (opioids)
Supportive: maintains integrity of body functions while pt recovers from illness/trauma (IV fluids)
Prophylactic: Prevents illness/undesired outcomes (vaccines)
Empiric: Based on clinical probabilities (antibiotics)
Explain the following:
Monitoring
Therapeutic Response
Adverse Effects
Toxic Effects
Monitoring: evaluating the effectiveness of the therapy
Therapeutic Response: beneficial effects
Adverse effects: unintended effects
Toxic effects: poisonous/harmful effects
Explain the following:
Therapeutic index
Low vs. High Therapeutic index
Ratio of a drug’s toxic level to the level providing therapeutic benefits
Low/Narrow: Greater likelihood of adverse reaction
High: Smaller likelihood of adverse reaction
Explain the following:
Tolerance
Dependence
Physical Dependence
Psychological Dependence
Tolerance: decreasing response to repeating drug doses
Dependence: physiologic or psychological need for a drug
Physical Dependence: physiologic need for a drug to avoid physical withdrawal symptoms
Psychological Dependence: Addiction- obsessive desire for the effects of a drug
Explain the following Effects:
Additive
Synergistic
Antagonistic
Incompatibility
Additive: Drugs w/ similar actions (1+1=2)
Synergistic: Drugs interact in a way that amplified the effect greater than the sum of the effects for each given alone (1+1= >2)
Antagonistic: Combination of the 2 drugs diminishes the effects (1+1=<2)
Incompatibility: 2 parenteral drugs/meds are mixed together- causes chemical deterioration of one or both (precipitation, color change, haziness)
What drug interactions would result from the following combinations:
Aspirin + Acetaminophen
Caffeine + Alcohol
Acetaminophen + Alcohol
Additive
Antagonistic
Synergistic- both are liver-toxic
Explain the following:
Pharmacologic Reaction
Hypersensitivity (allergic) Reaction
Idiosyncratic Reaction
Drug interaction
Teratogenic Effect
Mutagenic Effect
Carcinogenic Effect
Pharmacologic: normal effects
Hypersensitivity: immune system response to neutralize substance
Idiosyncratic: unexpectedly in particular pt
Drug interaction: unwanted effects of 2 drugs given together
Teratogenic Effect: damaging to fetus
Mutagenic Effect: permanent genetic composition changes in living organisms
Carcinogenic Effect: Cancer-causing
Explain pharmacognosy
Give 2 examples of animal sources of drugs
Study of natural drug sources like plants/animals/minerals
Porcine: Pig: Heparin/Insulin
Equine: Horse: conjugated estrogens
What is the treatment system based on for toxicology?
Prioritics: ABCs
Prevention of absorption or speed its elimination from body
How would renal disease affect half-life?
Would delay it due to excretion difficulties
