ATI chapter 46 Flashcards
Pharmacokinetics & routes of administration
________ refers to how medications travel through the body. Medications undergo a variety of biochemical processes that result in _______, distribution, ________, and excretion.
pharmacokinetics
absorption
metabolism
_______- the transmission of medications from the location of administration (GI tract, muscle, skin, or Subcutaneous tissue) to the __________
absorption
bloodstream
The most common routes of administration are ______( through the GI tract) and ________(by injection). Each of these routes will have a unique pattern of absorption—>the ____ of medication absorption determines how soon the med takes effect, The amount of meds absorbed determines its ______ , and the route of administration affects the rate and _______ of absorption.
enteral Parenteral rate intensity amount
What is a barrier to absorption for an oral route?
Medications must pass through the layer of epithelial cells that line the GI tract.
The Oral absorption pattern varies greatly to: stability and _______ of the meds, Gastrointestinal PH and ______ time, Presence of _____in the stomach or intestines, other meds currently being administered, forms of meds (______-coated, liquids)
solubility
emptying
food
enteric
What is a barrier to absorption for an subcutaneous & intramuscular route?
the capillary wall has large spaces between cells. therefore, there is no significant barrier.
The rate of absorption for Subcut & IM is determined by 1.) _______ of the medication in water. Highly soluble meds are absorbed in ___ to 30 minutes, poorly soluble meds are absorbed ______. 2.) blood ______ at the site of injection. Sites with ____ blood perfusion will have rapid absorption. sites with low blood perfusion will have slow absorption.
solubility 10 slower perfusion high
Intravenous has ___ barriers. The absorption pattern is _______-administered directly into the blood and ______-all of it reaches the blood
no
immediate
complete
_______ is the transportation of meds to sites of action by bodily fluids. Distribution may be influenced by: circulation, ______ of the cell membrane & plasma ______ binding.
Distribution
permeability
protein
Conditions that inhibit blood flow or perfusion, such as peripheral vascular or cardiac disease, may delay med distribution
circulation
The meds must be able to pass through tissues and membranes in order to reach its target area. Meds that are lipid-soluble or have a transport system can cross the blood-brain barrier of the placenta.
Permeability of the cell membrane
Medications ______ for protein binding sites within the bloodstream, primarily ______. the ability of a med to bind to a protein can affect how much of the med will leave and travel to target tissues. Two meds can compete for the same binding sites, resulting in ________
compete
albumin
toxicity
_______ (biotransformation) changes meds into less active forms or inactive forms by the action of _________. this occurs primarily in the _____, but also takes place in the kidneys, lungs, bowel, and blood.
metabolism
enzymes
liver
What are some factors that influence the rate of medication metabolism?
- Age
- An Increase in certain medication-metabolizing enzymes
- First-pass effect
- similar metabolic pathways
- nutritional status
-Age has what influencing factor on Metabolism?
infants have limited meds metabolizing capacity. Aging process varies from individual-individual. in general, hepatic (liver) meds metabolism tends to decline with age.
An increase in certain meds-metabolizing enzymes has what influencing factor of metabolism?
can cause a particular med to be metabolized sooner, requiring an increase in dosage of that med to maintain a therapeutic level. can also cause an increase in metabolism of other meds that are being used concurrenly
What does the first pass effect have on meds metabolism?
some meds are inactivated on their first pass through the liver & must be given by a nonenteral route b/c of their high first pass effect. These meds are usually givin by routes such as SL or IV.
How does similar metabolic pathways have on meds-metabolism?
when two medications are metabolized by the same pathway, they can interfere with the metabolism of one or both of the meds. in this way, the rate of metabolism can be decreased for one or both of the meds leading to meds accumulation
How does nutritional status affect meds metabolism?
a malnourished client may be deficient in the factors that are necessary to produce specific meds-metabolism enzymes. consequently, meds metabolism may be impaired.
________is the elimination of meds from the body, primarily through the kidneys. can also take place through the liver, lungs, bowel & exocrine glands. Kidney disfunction may lead to an ______ in duration & intensity of medication response.
Excretion
increase
_____ medication levels can be regulated to control medication responses. Medication dosing attempts to maintain plasma levels between the minimum effective _______(MEC) & the _______ concentration.
Plasma
concentration
toxic
A plasma medication level is in the _______ range when it is effective and not toxic. T levels are well established for many meds, and these levels can be used to monitor a client’s _____.
therapeutic
response
Meds with a ____ Therapeutic index (TI) have a wide safety margin. therefore , there is no need for routine ____ med level monitoring. Meds with a low TI should have serum med levels monitored closely. Monitor peak levels based on the _____ of administration.
high
serum
route
For example: an oral med may have a peak of 1-3 hr after administration. If the med is given IV, the peak time might occur within 10 mins.
- refer to a drug reference or a pharmacist for specific med peak times.
- for trough levels, blood is drawn immediately before the next med dose, regardless of the route of administration.
____-_____ refers to the period of time needed for the med in the body to be reduced by 50%. may be affected by _____ & _____ function. usually takes ____ half lives to achieve a steady state of serum concentration (medication ______=medication metabolism and ________)
Half-life liver & kidney four intake excretion
