Pharm basics part 3 Flashcards
4 processes: Absorption, distribution, metabolism, excretion
Diff routes - sig; routes most sig for absorption
Liver responsible for metabolism
Drug excreted from kidneys - responsible for excretion
What body does with med
Pharmacokinetics
How the med affects the body - what drug do to body; how actually work to exert effect; part of distribution phase of pharmacokinetics - drug has to get distributed to diff parts of body (tissues, organs) to exert an effect
Drugs act at specific areas on cell membranes called receptor sites
Drugs work by change/altering existing physiological and biochemical processes - utilize receptor sites in lot diff ways
Medications gen work in one of four ways:
Pharmacodynamics
Have Receptor sites all over body
Receptor sites Normally bind things like hormones, neurotransmitters, growth factors, etc.: hormones: insulin, cortisol, ADH - attach to specific receptor sites; neurotransmitters: AcH, epinephrine, norepinephrine
Drugs act at specific areas on cell membranes called receptor sites
1.To replace or act as substitutes for missing chemicals - T1DM: no insulin secretion: give exogenous/synthetic insulin to replace what missing since missing insulin
2.To increase or stimulate certain cellular activities - do with agonist drugs; beta2 agonist - beta2 receptors part sympathetic NS: act sim to sympathetic NS
3.To depress or slow cellular activities - beta antagonists/blocker (opp beta agonist); antihistamines
4.To interfere with the functioning of foreign cells, such as invading microorganisms or neoplasms leading to cell death: antibiotics - working to kill that microorganism; chemo - targeted to kill cancer cells
Medications gen work in one of four ways:
types receptors and How meds interact with them
Agonists
Antagonists
Drug–Enzyme Interactions
Selective Toxicity
Receptor theory: types
Drugs interact directly with receptor sites and causes same activity that natural chemicals would
Cause same activity of natural chemicals would cause at that site
Ex: insulin - interacting with same receptor site as indogenous insulin and causing same activity; beta-agonist
Mimicking what body norm do
Occupy same exact receptor site and work exactly like normal areas of body would
Agonists
blocks/prevents some kind of stimulation/rxn from occurring
Ex: beta-blockers - blocking beta receptor sites of symp NS; anti-histamines
Means blocked/prevented - antagonist, blocker, anti
Occupy receptor sites for natural chemical so no longer get in receptor sites
Antagonists
Drugs that Interferes with enzyme systems that act as catalysts for chemical reactions
Most time drugs are blocking some point of this enzyme interaction so norm effect cannot occur
One interruption (drug) in cascade can block the normal cell function
Ex: Angiotensin converting enzyme inhibitor (ACE-inhibitor) - RAAS - conversion Angiotensin I to II and need ACE because acts as catalyst of conversion from I to II and if inhibit enzyme prevent conversion: lowering BP
Drug–Enzyme Interactions
Ability of a drug to attack only those systems found in foreign cells
Drugs trying to attack certain types of foreign cells
Ex: Penicillin (antibiotic); certain types of chemotherapy drugs - trying to do is directly target cells
Selective Toxicity
Parasympathetic -
Sympathetic -
Receptor theory: ANS
major neurotransmitter: AcH; “rest and digest”
major actions: decreases the HR, constrict bronchioles - resting not need breathing heavy or oxygenating well because not utilizing lot major organs, increases digestion/GI tract, increases/helps to stimulate urination
Parasympathetic -
“fight/flight”
Major actions: increase HR, bronchodilation, increase rate and depth of breathing, slowing of GI/digestive tract, decreased urination - need O2 to tissues
Sympathetic -
Mimics acetylcholine - major neurotransmitter
Agonist (cholinergic agonist) - cholinergic referring to parasym NS: mimicking normal actions of parasym NS
Antagonist (cholinergic-blocking/er) - blocking; aka anti-cholinergic drugs; blocking parasymp NS - because helpful in conditions
ANS: parasym branch
Increases saliva production
Slows heart rate
Constricts bronchioles
Stimulates digestive process
Increases urination
Common use: Alzheimer’s disease - loses neurons (die); goal is increase amount AcH available for use in brain; give this increases amount AcH and mimics norm actions; also have adverse effects because not just affect brain because goes to entire body
Agonist (cholinergic agonist) - cholinergic referring to parasym NS: mimicking normal actions of parasym NS
Decreases saliva/secretions
Increased heart rate
Relaxes bronchioles
Decreased GI motility and peristalsis
Urinary retention
Drowsiness, disorientation
Uses: bowel and bladder disorders - overactive bladder - urinating too much - block parasymp activation which increases urination and block it so not urinate as frequently but also goes systemic so have those adverse effects, Parkinson’s disease, asthma
Also called: anti-cholinergic
Antagonist (cholinergic-blocking/er) - blocking; aka anti-cholinergic drugs; blocking parasymp NS - because helpful in conditions
Adrenergic agonist - mimics action of SNS
Adrenergic antagonist (adrenergic-blocking) - some kind of blocker of some specific cells in SNS
ANS: SNS branch
Tachycardia and vasoconstriction
Increases BP
Increases rate and depth of breathing
Bronchodilation
Decreased GI motility
Glycogenolysis (increased blood glucose)
Constricts bladder sphincter
Uses: cardiac and respiratory
Other name: sympathomimetic - mimicking SNS
Adrenergic agonist - mimics action of SNS
Slows heart rate
Lowers blood pressure
Bronchoconstriction
Masks s/s hypoglycemia
Urinary incontinence
Uses: HTN, BPH
Other name: alpha-, beta-blockers: blocking receptors in sympathetic branch
Block receptor sites: Blocking norm action of SNS - PSNS symp
Adrenergic antagonist (adrenergic-blocking) - some kind of blocker of some specific cells in SNS
The nurse is reviewing a medication list for a client. The nurse knows which drug acts as an antagonist?
A.Oxycodone
B.Ciprofloxacin
C.Cyclophosphamide
D.Oxybutynin
Answer: D
Rationale: Oxybutynin is an anticholinergic drug used to treat overactive bladder. Oxycodone is an agonist of opioid receptors, ciprofloxacin is an antibiotic that selectively targets bacteria, and cyclophosphamide directly targets cancer cells.
Applied action to drug information
Oxycodone - opioid agonist
Ciprofloxacin - antibiotic - selective toxicity targeting microorganisms
Cyclophosphamide - used for cancer; selective toxicity targeting cancer
Infants and children
Pregnancy/lactation
Older adults
Lifespan considerations
Selected medications available for use in infants/children less than 2 years old - Only few select meds available to use in such age groups
Pediatric dosing differs from adult dosing (many meds weight-based) - gen use whatever dosing present for adult; peds do weight-based so dosing lot more accurate because growing a lot
Educate parents: - properly everything would educate adult pats so can properly take care of children
Infants and children
Parents need know this and Must discuss with healthcare provider (HCP) prior to any medication use that give to child at age including OTC - run by pediatrician first
Selected medications available for use in infants/children less than 2 years old - Only few select meds available to use in such age groups
Appropriate use
Proper dosing
Correct administration
Potential adverse effects (AE) and when to call
Educate parents: - properly everything would educate adult pats so can properly take care of children
The nurse caring for a pediatric patient calculates the safe range for a prescribed medication. Based on the calculation, the dose ordered exceeds the high limit. What should the nurse do next?
A.Contact the prescriber immediately.
B.Administer half the prescribed dose.
C.Proceed with administration of the prescribed dose.
D.Contact pharmacy to obtain the medication in a different potency.
Answer: A
Rationale: The nurse should contact the prescriber immediately and before administering the medications. Giving only half the prescribed dose is making a prescribed order which is not within the scope of practice for the nurse. Pharmacy cannot make treatment changes without the direction of the prescriber.
Teratogenic drugs:
Each new drug assigned a pregnancy/lactation category - risk to developing fetus if pregnant woman takes meds
Categories indicate drug’s potential or actual teratogenic effects
Medications during pregnancy should not be used without discussing with provider (including OTC) - meds taking should be approved even if OTC because indiviudalized and want make sure taken safely
Pregnancy safety
Cross placental barrier: Potential/actual harm to developing fetus
Many drugs can be this - all drugs assigned pregnancy category
Teratogenic drugs:
Benefit vs. risk
Medications during pregnancy should not be used without discussing with provider (including OTC) - meds taking should be approved even if OTC because indiviudalized and want make sure taken safely
A:
B:
C:
D:
X:
Pregnancy categories
adequate studies humans; no evidence of risk; very few drugs are this; not enough pats willing to be that person in study; cannot classify many as this
A:
studied in animals who are pregnant; risk unknown for human because never studied in humans - gen speaking safer end of drugs; no risk to animals
B:
studied in animals who are pregnant and reveal adverse effects to fetus - not resulted in major abnormalities/developmental delays/long-term harmful to developing fetus but AE have been found; not in place where category D/X
C:
studies confirm fetal risk; benefits > risk; see probs in fetus when studied in animals and provider has think about condition of mom if drug more beneficial to mom and if benefits to mom outweigh risk to fetus
D:
observation or studies fetal abnormalities - will be fetal abnormalities and pregnant woman should never take this drug
X:
Not always have pregnancy categories and stemmed out of Europe; early 1900s not many drugs and created many and not know would be risk to fetus; action sprung where give thalidomide for morning sickness
Really Effective for morning sickness - given to all pregnant woman and helping morning sickness and thousands babies born with severe fetal abnormalities; extremities severely affected; where categories came from: drug info and help guide drug use for woman
Dr. Frances Oldham Kelsey (FDA) banned sale in US after determining research inadequate
Teratogenicity ex: drug thalidomide causes birth defects 1960s
Led to 1965 Kefauver-Harris Act
Dr. Frances Oldham Kelsey (FDA) banned sale in US after determining research inadequate
Think about when admin meds and how changes alter pharmacokinetics of drugs
Cardiovascular
Gastrointestinal
Hepatic
Renal
Older adult: physiological chages of aging related to pharm
Decreased cardiac output - hearts not pumping as effectively: affects distribution of drug
Cardiovascular
Increased gastric pH and decreased peristalsis
Decreased absorption
Gastrointestinal
Decreased enzyme production and decreased blood flow to liver
Hepatic
Decreased blood flow, GFR, and overall function
Renal
Absorption
Distribution
Metabolism
Excretion
Risk for toxicity in older adults gen speaking is greatest concern - what monitoring older adults for: toxicitiy meds: mostly stemming from what know about liver and kidney func
Older adult: pharmocokinetic alterations
Changes of aging can result in decreased absorption of oral drugs - drugs not absorped as well: decreased therapeutic effect (not as effective) potentially
Absorption
Decreased total body water increases concentration of med; risk toxicity
Decreased protein (albumin); greater amount of free drug; risk toxicity
Changes to this; increased risk for toxicity
Distribution
Enzyme activity decreased due to decreased function; increased risk toxicity; liver not working as well - slows down - not metabolse drugs - increased risk toxicity
Metabolism
Decreased number of nephrons and GFR; increased risk toxicity; kidneys start shut down and not work as well as age - not same number working nephrons - meds not excreted as effectively - risk toxicity
Excretion
What does the nurse identify as a pharmacokinetic change that occurs in older adults?
A.Gastric pH is more acidic.
B.Fat content is decreased because of increased lean body mass.
C.There is increased production of proteins by the liver.
D.The number of intact nephrons is decreased.
Answer: D
Rationale: In older adults, the gastric pH is less acidic because of a gradual reduction in the production of hydrochloric acid in the stomach, fat content is increased because of decreased lean body mass, and there is decreased production of proteins by the aging liver and reduced protein intake. It is correct that the number of intact nephrons decreases in older adults.
