Chapters 1-4 Flashcards
What is pharmacology?
Study of biological effects of chemicals
What are drugs?
Chemicals that are introduced into a body with the intent to cause a change
What is pharmacotherapeutics?
Use of drugs to treat, prevent, and diagnose disease
What are controlled substances?
Any drug with an abuse potential (physical or psychological dependence)
Who monitors the prescription, distribution, storage, and use of controlled substances?
DEA
What is the Schedule of Controlled Substances?
Schedule I - Schedule V
C-I through CV
I = most risky (Ex: Heroin)
V = least risky of the risky substances (Ex: antitussives)
What is teratogenicity?
Adverse effects on a fetus
What is Category X?
Proven to have substantial adverse effects on a fetus
Brand Name or Trade Name of drug
- Name given by drug company once approved by FDA
- Given by companies that research, test, and manufacture drug
- More expensive
- Drug formula is patented
- Insurance companies may not cover cost
Generic Name of drug
- original name given to drug when submitted to FDA
- Companies only manufacture the drug
- significantly less expensive
- Same active ingredient
- Most states require generic drugs
What does DAW mean?
Dispense As Written
OTC drug concerns
- can mask s/s of underlying disease
- can interact/interfere with Rx drug therapies
- Serious overdoses can occur if not taken as directed
- Patients often do not report them to provider
What is Pharmacodynamics?
How the DRUG affects the body
What is Pharmacokinetics?
What the body does with the drug….
How the body acts on the drug
What are the 4 main mechanisms of action?
- Receptor Action
- Physical Action
- Act on other chemicals in the body
- Enzyme/Metabolic Action
What is involved in the receptor MOA?
Drugs act on receptor sites on the cell membranes
What is an Agonist?
drug that binds to the receptor site to INCREASE or STIMULATE a normal response
What is an Antagonist?
drug that binds to the receptor site to DEPRESS, BLOCK, or SLOW the normal response
What is a physical MOA?
*Changes the physical properties of cell or body fluids
*Such as: damage the cell wall or alter the pH
What is a Chemical MOA?
Creating chemical reactions in the body
What is an Enzyme/Metabolic MOA?
Processes in the body requiring multiple steps to have an effect => drugs interfere with one of these steps by stopping, delaying, or speeding it up
What is onset?
When a drug starts working
What is peak?
When the drug is at its highest
What is duration?
How long a drug works
What is critical concentration?
Amount of drug needed to cause a therapeutic effect
What is a loading dose?
Higher dose than normally used for treatment to get to a critical concentration faster
What is dynamic equilibrium?
The actual drug level in the body, dependent on how drug is absorbed and metabolized
What is the Therapeutic Index?
Ratio comparing the blood concentration at which a drug becomes toxic vs the concentration at which the drug is effective
What is absorption?
Starts when the drug enters the body, ends when it reaches circulating fluids and tissues
What is Passive Transport?
across a concentration gradient - no energy required
What is Active Transport?
Uses energy to move drug across a cell membrane, against the concentration gradient
*More important in excretion
What is filtration?
movement through pores of the cell membrane
*Pinocytosis
What are factors that influence absorption?
- Route: IV/IM are the fastest
- Solubility: water and lipid soluble are “best”
- Tissue Perfusion: needs to be adequate
- Ionization: No charge is “best”
- Size: smaller is absorbed faster
What is Distribution?
Movement of drug through systemic circulation to the body’s tissues
Factors affecting distribution
- Solubility
- Ionization
- Tissue Perfusion
What does protein binding have to do with distribution?
- Some (?) molecules need to be bound to a protein to be carried
- It’s difficult for a protein bound molecule to cross a cell membrane
- Only “free” unbound particles can cause a therapeutic effect
- Some are tightly bound vs loosely bound
- There is competition for protein-binding sites (?)
How does the blood-brain barrier affect distribution?
Only lipid soluble drugs can cross the barrier
What is Metabolism of a drug?
Process by which drugs are changed to less active chemicals
What is the organ responsible for metabolism of drugs?
LIVER
What is the first-pass effect?
Oral drugs go from the small intestine to the liver before circulation.
Liver enzymes deactivate a large portion of the drug
Inactive portion gets excreted
Active portion gets transported to the target tissue
How does Parenteral administration affect drug metabolism?
Parenteral: IV/IM
* No first pass effect
* Lower med doses needed
* Still metabolized in the liver
What are Hepatic Enzyme Systems and how do they affect drug metabolism?
They are enzyme systems responsible for metabolizing drugs
* Cytochrome P450 system is one of the systems commonly used by many drugs
* Drugs can stimulate or inhibit enzyme systems
* If a drug inhibits an enzyme system, it can build up and cause toxicity
* If two drugs use the same enzyme system, they should NOT be used together
* If the drugs stimulate the enzyme system, they’ll be metabolized more quickly and the drugs may be less effective
What is Elimination in regards to drugs?
Removal of the drug from the body
What is the organ responsible for elimination of drugs?
KIDNEYS
What is the glomerular filtration method of elimination?
For WATER SOLUBLE drugs
Water and water soluble components pass from the blood into the renal tubule to be excreted
What is the Active Transport method of elimination?
For NON-water soluble drugs
*Exchange drug molecules for acid or bicarbonate molecules in order to get into the renal tubule
*Have to consider renal function: kidney impairment could lead to impaired excretion and increased risk of toxicity
What is Half-Life?
The time it takes for the amount of a drug in the body to decrease to one half of the previous dose
Factors that could affect it: Metabolism, Distribution, Elimination
Factors influencing drug effects
- Weight (studies are all done on avg. 150lb person)
- Age (elderly => altered metabolism and excretion)
- Gender (in males => IM route is faster because of more vascular muscles)
- Physiological (hydration, etc)
- Pathological Factors (disease effects)
- Genetic factors
- Immunological factors
- Environmental factors
- Tolerance
- Accumulation
Drug Interactions
When 2 or more substances are taken together.
Happens @ the points of absorption, metabolism, excretion, site of action
Alteration of therapeutic effect
Increase in adverse effects
Issues can be serious with drugs with a narrow margin of safety
Drug - Drug or Drug-Alternative Therapy Interactions
interaction between prescription drugs, OTC drugs, herbal supplements, vitamins
Drug - Food Interactions
Typically occurs with direct contact in the stomach
Exception: Grapefruit juice (If there is an interaction, grapefruit juice should not be ingested at all during the drug therapy)
Oral meds are usually best on an empty stomach
Types of Adverse Effects
- Primary Actions: too much of the desired effect
- Secondary Actions: effects that were not intended
- Drug Allergy: antibodies are formed to a particular drug, upon re-exposure, reaction occurs, could also be cross-allergies between drugs in same class
Anaphylactic Drug Reaction
IMMEDIATE
Release of histamine => mucus membrane swelling, bronchi constriction
S/S: Hives, rash, trouble breathing, changes in BP, dilated pupils, diaphoresis, increased HR, panic - impending doom, respiratory arrest
Interventions:
Stop drug
Epinephrine (Subq)
Notify provider
Prevention: med bracelet, epi kit
Dermatologic Reactions of drugs
Rashes, Hives
Stevens-Johnson Syndrome
Stomatitis
Rashes and Hives: Assessment
Could be adverse reaction or allergy (systemic = allergy)
Check for rashes, lesions
Systemic: enlarged lymph nodes, fever, hepatomegaly
What is Stevens-Johnson Syndrome?
- Dermatologic Reaction
- Very rare but serious
- dark red papules on extremities
- appear in a circle/ring shape
- no itching or pain
Interventions for Dermatologic Reactions
Mild cases: benefit vs. discomfort
skin care
teaching
medications to treat effects
What is stomatitis?
Dermatologic Reaction
Inflammation of mucus membranes
Stomatitis assessment
look for gingivitis, glossitis, difficulty swallowing, bad breath, pain in mouth or throat
Stomatitis Interventions
Frequent mouth care
Frequent small meals with non-irritating foods
dental consultation
medications: anti-fungal, local anesthetics
Liver/Hepatic Injury from Toxic effects of drugs
Liver metabolizes drug, first pass effect
Impairment = possible toxicity of drug
Assessment for Liver/Hepatic Injury
CNS: Fever, malaise
GI: N/V, abdominal pain, urine or stool color (dark brown urine, pale stool)
Skin: Jaundice (also sclera of eyes)
Changes in Labs:
elevated AST, ALT
abnormal bilirubin levels
changes in clotting factors: PT/INR, PTT
Interventions for hepatic injury
discontinue the drug
small frequent meals
skin care
cool environment
rest periods
Kidney Injury from toxic effects of drugs
Kidneys excrete drugs
Impairment = accumulation of drug in body
Assessment for Kidney injury
CNS: fatigue, malaise, irritability
Skin: Rash
Edema
Decreased urine output
Changes in labs:
Elevated BUN, Cr
Decreased HCT
Electrolyte imbalances
Interventions for Renal injury
Positioning (for edema)
diet/fluid restrictions
skin care
electrolyte replacement
rest
may need to discontinue drug
may need dialysis
Toxic effects of drugs: Poisoning
damage to multiple body systems due to overdose
emergency life support measures may be needed
death can occur
Toxic effects of drugs: CNS
Assessment
- Confusion, delirium, hallucinations
- Insomnia, drowsiness, bizarre dreams
- Hyper or hypo-reflexia
- Numbness, tingling, paresthesia (pins and needles)
- Seizures
Toxic effects of drugs: CNS
Interventions
- safety measures to prevent injury
- patient education to prevent injury
- orientation as needed
- decrease dose or discontinue drug
Toxic Effects of drugs: Teratogenicity
Category X
Pregnant women must be informed and must consent
Some drug effects are not known (unethical to run studies)
Placebo Effect
A positive attitude can increase effects
Absolute Contraindication
NEVER administer
Life Threatening
Relative Contraindication
Discuss benefit vs risk
contact provider
Caution
may administer with additional nursing considerations
Evaluation of drug therapy
Patient Response to drug:
Therapeutic effect
Adverse effects
Effectiveness of teaching plan
Effectiveness of comfort and safety measures
Compliance of regimen
Nursing Responsibilities in Pharmacology
- Administer drugs
- Assess drug effects
- Intervene when adverse effects occur
- Provide patient teaching
- Monitor to prevent medication errors
Reporting of medication errors
Nurse => report to institution
Institution => FDA and US Pharmacopeia
