Exam 1 Terms Flashcards
Any chemical that can affect living processes
Drug
Study of drugs and their interactions with living systems
Pharmacology
Study of drugs in humans
Clinical pharmacology
The use of drugs to diagnose, prevent, or treat disease
Or to prevent pregnancy
Therapeutics AKA pharmacotherapeutics
3 most important properties of an ideal drug
Effectiveness (most important)
Safety
Selectivity
How to minimize adverse effects
Always know:
- *The major adverse effects of the drug
- Early signs that an adverse reaction is developing
- The times when these reactions are likely to occur
- Interventions that can minimize discomfort
Take a thorough drug history
Monitor adverse interactions that are known to occur
Avoid drug interactions
Act that created the classes of Scheduled drugs
Controlled Substances Act, 1970
3 types of drug names
Chemical name
Generic name (nonproprietary)
Trade name (proprietary)
The study of drug movement throughout the body
Pharmacokinetics
Movement of a drug from its site of administration into the blood
Absorption
Movement of drugs throughout the body
Distribution
3 factors drug distribution is determined by
Blood flow to tissues
Exiting the vascular system
Entering cells
Where does drug metabolism most often take place?
In the liver
What is most drug metabolism in the liver performed by?
The P450 system (hepatic microsomes enzyme system)
The removal of drugs from the body
Excretion
Steps in renal drug excretion
Glomerular filtration
Passive tubular reabsorption
Active tubular secretion
What is the objective of drug dosing?
To maintain plasma levels within the therapeutic range
What is the therapeutic range?
When there is enough drug to produce therapeutic responses (above the minimum effective concentration) but not so much that toxicity results (below toxic concentration)
The time required for the amount of drug in the body to decrease by 50%
Half-life
The study of the biochemical and physiologic effects of drugs
Pharmacodynamics
The relationship between the size of an administered dose and the intensity of the response produced
Dose-response relationship
What does the dose-response relationship determine?
The minimum amount of drug to be used
The maximum response a drug can elicit
How much to increase the dosage to produce desired increase in response
The largest effect that a drug can produce
Maximal efficacy
The amount of drug that must be given to produce an effect
Relative potency
Special chemicals in the body that most drugs interact with to produce effects
Receptors
What occurs when a drug binds to a receptor?
It mimics or blocks the action of the endogenous regulatory molecules
And increases or decreases the rate of the physiologic activity normally controlled by that receptor
Why is it good for a drug to be more selective?
The more selective a drug is, the fewer side effects it will produce
Molecules that activate receptors
Agonists
What do agonists do?
Activate receptors
Make processes go faster or slower
Characteristics of agonists
Affinity
High intrinsic activity
Prevent receptor activation by endogenous regulatory molecules and drugs
Antagonists
Characteristics of antagonists
Affinity
No intrinsic activity
What can cause a receptor to be more sensitive?
Continuous exposure to an antagonist
What causes a receptor to be desensitized?
Continuous exposure to an agonist
Formula used to measure interpatient variability
ED50
Measure of a drug’s safety
Therapeutic index
What will the therapeutic index be like in a safer drug?
Larger/higher therapeutic index
What will the therapeutic index be like in a less safe drug?
Smaller/lower therapeutic index
Which types of drug-drug interactions alter absorption?
Interactions of oral medications
Ways distribution is altered with drug-drug interactions
Competition for protein binding
Alteration of extra cellular pH
Ways renal excretion is altered with drug-drug interactions
Filtration
Reabsorption
Active secretion
Most important and complex mechanism in which drugs interact
Altered metabolism
Cytochrome P450 group of enzymes
What occurs when drugs interact with each other at the same receptor?
Almost always inhibitory (agonist/antagonist)
What occurs when drugs interact with each other at separate sites?
May be potentiative (work better together)
Or
Inhibitory
How to minimize adverse drug-drug interactions
**Take a drug history
*Monitor the patient for early signs of toxicity
Minimize number of drugs a patient receives
Be aware of possible illicit drug use
Adjust dose when metabolizing inducers are added or deleted
Adjust timing of administration to minimize interference with absorption
Be extra vigilant when patient is taking drug with low therapeutic index
How does grapefruit juice affect drugs?
Affects drug metabolism and the P450 enzymes
Inhibits the metabolism of certain drugs, increasing the drugs’ blood levels
Example of a drug that is affected by grapefruit juice
Cuclosporine
Any harmful, unintended, and undesired effect that occurs at normal drug doses
Adverse drug reactions
Nearly unavoidable secondary drug effect produced at therapeutic doses
Side effect
Adverse drug reaction caused by excessive dosing
Toxicity
Immune response to a drug
Allergic reaction
Uncommon drug response resulting from a genetic predisposition
Idiosyncratic effect
The opposite of the intended drug response
Paradoxical effect
Disease produced by a physician or by drugs
Iatrogenic disease (drug-induced disease)
State in which the body has adapted to drug exposure in such a way that an abstinence syndrome will result if drug use is discontinued
Physical dependence
Cancer causing effect of drugs
Carcinogenic effect
Drug-induced birth effect
Teratogenic effect
Signs of liver injury:
Jaundice
Dark urine
Light-colored stools
Nausea
Vomiting
Abdominal discomfort
Loss of appetite
Malaise
How to monitor the liver for toxicity
Watch for signs of jaundice
Monitor liver function tests
How to monitor the kidney for signs of toxicity
Routine urinalysis
Serum creatinine level (with periodic creatinine clearance testing)
Ways to monitor bone marrow for toxicity
Periodic blood cell counts
Strongest safety warning a drug can carry and still remain on the market
Black box warnings
Potentially severe side effects black box warnings warn for
Life threatening dysrhythmias
Suicidality
Major fetal harm
Avoid teratogenic drug during pregnancy
Top human factors that cause medication errors
Performance deficits (most common)
Knowledge deficits
*miscalculation of dosage
Decreased responsiveness to a drug as a result of repeated drug administration
Tolerance
Three types of drug tolerance
Pharmacodynamic tolerance (long-term administration)
Metabolic tolerance (accelerated drug metabolism)
Tachyphylaxis (repeated dosing over a short time)
Ability of a drug to reach the systemic circulation from its site of administration
Bioavailability
Type of administration that uses bioavailability
Oral
Study of how genes affect individual drug responses
Pharmacogenomics
The passing of traits from one generation to another
Genetics
All of a person’s genes
Genome
Benefits of pharmacogenomics
Individualized and more specific drug therapies
Reduces adverse drug reactions
Age range for pediatric patients
All patients younger than 16 years old
What are neonates and infants more at risk for relation to pharmacokinetics? Why?
Elevated drug levels = more intense response
Delayed elimination = prolonged response
Immaturity of organs
How is absorption affected with oral meds in neonates and infants?
May be prolonged
How is absorption affected with IM medications for neonates and infants?
Neonates: Delayed due to low blood flow during first few days of life
Early infancy: More rapid
How is absorption affected with transdermal meds for infants?
Blood flow to skin is greater because skin is very thin. So infants are at increased risk of toxicity from topical drugs
How is distribution of drugs affected in neonates and infants?
- Reduced dosage needed because
- limited drug/protein binding
- Amount of serum albumin is relatively low
- blood brain barrier not fully developed (drugs have easy access to CNS)
In which age group do children metabolize drugs faster than adults?
Until 2 years of age
Goal of treatment for older adults?
Reduce symptoms and improve quality of life
How is absorption affected in older adults?
Rate of absorption slows
How is distribution affected in older adults?
Decreased protein binding of drugs and increased levels of free drugs
How is metabolism affected in older adults?
Hepatic metabolism declines
Half-lives of some drugs may increase, prolonging responses
Some oral drug responses may be enhanced
How is excretion affected in older adults
Renal function declines causing potential for drug accumulation
Most important cause of adverse drug reactions in older adults
Drug accumulation due to reduced renal excretion
Nursing considerations for older adults taking medications
Renal function should be assessed
Using creatinine clearance rather than serum creatinine
(Creatinine levels may be normal even though kidney function is greatly reduced)
Nursing considerations to reduce ADRs in older adults
Monitor patients response and plasma drug levels
