Part 1.2: drugs and the body Flashcards
Pharm
what happens to a drug from the time it enters the circulating fluid; IV admin causes the drug to directly enter the circulating blood, bypassing the many complications of ___ from other routes
absorption (step 1 in pharmacokinetics)
the movement of substances across a cell membrane against the concentration gradient; this process requires the use of energy
active transport
synthetic chemicals used to interfere with the functioning of foreign cell populations, causing cell death; this term is frequently used to refer to the drug therapy of neoplasms, but also drug therapy affecting any foreign cell
chemotherapeutic agents
the concentration a drug must reach in the tissues that respond to the particular drug to cause the desired therapeutic effect
critical concentration
movement of a drug to body tissues; the places where a drug may be distributed depend on the drug’s solubility, perfusion of the area, cardiac output, and binding of the drug to plasma proteins
distribution (step 2 in pharmacokinetics)
process by which the presence of a chemical that is biotransformed by a particular enzyme system in the liver causes increased activity of that enzyme system
enzyme induction
removal of a drug from the body; primarily occurs in the kidneys, but also skin, lungs, bile or feces
excretion (step 4 of pharmacokinetics)
a phenomenon in which drugs given orally are carried directly to the liver after absorption, where they may be largely inactivated by liver enzymes before they can enter the general circulation; oral drugs frequently are given in higher doses than drugs given by other routes because of this early breakdown
first-pass effect
the passage of water and water-soluble components from the plasma into the renal tubule
glomerular filtration
the time it takes for the amount of drug in the body to decrease to one half of the peak level it previously achieved
half-life
liver enzymes tightly packed together in the hepatic intracellular structure, responsible for the biotransformation (metabolism) of chemicals, including drugs
hepatic microsomal system
use of a higher dose than what is usually used for treatment to allow the drug to reach the critical concentration sooner
loading dose
movement of substances across a semipermeable membrane with the concentration gradient; this process does not require energy
passive diffusion
the study of the interactions between the chemical components of living systems and the foreign chemicals, including drugs, that enter living organisms; the way a drug affects a body
pharmacodynamics
the study of genetically determined variations in the response to drugs
pharmacogenomics
the way the body deals with a drug, including absorption, distribution, biotransformation, and excretion
pharmacokinetics
documented effect of the mind on drug therapy; if a person perceives that a drug will be effective, the drug is much more likely to actually be effective
placebo effect
specific areas on cell membranes that react with certain chemicals to cause an effect within the cell
receptor sites
property of a chemotherapeutic agent that affects only systems found in foreign cells without affecting healthy human cells (e.g., specific antibiotics can affect certain proteins or enzyme systems used by bacteria but not by human cells)
selective toxicity
the actual concentration that a drug reaches in the body results from a ____ _______ involving the rate of:
- absorption from site of entry
- distribution to the active site
- metabolism in the liver
- excretion from the body
Dynamic equilibrium
Is IM or SC absorbed faster by the body?
IM
T/F: if a medication is administered directly into the blood system, the absorption step is skipped
TRUE
Slowest route to be absorbed?
Oral
Why might an oral medication be coated, or in capsule form?
To prolong the breakdown of compounds by the acidic environment of the stomach
Why might food in the stomach change the way that oral medications are absorbed?
when food is present, stomach acidity is higher, and also empties slower, which exposes the medication to the acidic environment for longer and can speed up the breakdown of the medication.
To block this effect, many drugs may be given 1-2 hours before/after meals.
T/F: the gender of individuals changes the rate that medications are absorbed by IM injection
True.
Men have more vascular muscles than women do, which means that doses administered to men reach a peak level faster.
Factors that affect the absorption of IM medications (3)
- temperature of muscle: cold = vasoconstriction, decreases absorption. hot = vasodilation, increases absorption
- perfusion or blood flow to muscles
- fat content of muscle
Factors affecting PO absorption (4)
- acidity of stomach
- length of time in stomach
- blood flow to GI tract
- presence of interacting foods or drugs
- The half-life of a drug
a.is determined by a balance of all pharmacokinetic processes.
b.is a constant factor for all drugs taken by a patient.
c.is only influenced by the fat distribution of the patient.
d.can be calculated with the use of a body surface nomogram.
a) determined by a balance of all pharmacokinetic processes
- Much of the biotransformation that occurs when a drug is taken occurs as part of
a.the protein-binding effect of the drug.
b.the functioning of the renal system.
c.the first-pass effect through the liver.
d.the distribution of the drug to the reactive tissues.
c) the first pass effect through the liver
- Chemotherapeutic agents are drugs that
a.are used only to treat cancers.
b.replace normal body chemicals that are missing because of disease.
c.interfere with foreign cell functioning causing cell death, such as invading microorganisms or neoplasms.
d.stimulate the normal functioning of a cell.
c) interfere with foreign cell functioning causing cell death
- Receptor sites
a.are a normal part of enzyme substrates.
b.are protein areas on cell membranes that react with specific chemicals.
c.can usually be stimulated by many different chemicals.
d.are responsible for all drug effects in the body.
b) are protein areas on cell membranes that react with specific chemicals
- Selective toxicity is
a.the ability of a drug to seek out a specific bacterial species or microorganism.
b.the ability of a drug to cause only specific adverse effects.
c.the ability of a drug to cause fetal damage.
d.the ability of a drug to attack only those systems found in foreign or abnormal cells.
d) ability of a drug to attack only those systems found in foreign or abnormal cells
- When trying to determine why the desired therapeutic effect is not being seen with an oral drug, the nurse should consider
a.the blood flow to muscle beds.
b.food altering the makeup of gastric juices.
c.the weight of the patient.
d.the temperature of the peripheral environment.
b) food altering the makeup of gastric juices
- J.B. has Parkinson disease that has been controlled for several years with levodopa. After he begins a health food regimen with lots of vitamin B6, his tremors return, and he develops a rapid heart rate, hypertension, and anxiety. The nurse investigating the problem discovers that vitamin B6 can speed the conversion of levodopa to dopamine in the periphery, leading to these problems. The nurse would consider this problem
a.a drug–laboratory test interaction.
b.a drug–drug interaction.
c.An accumulation effect.
d.a sensitivity reaction.
b) drug-drug interaction
- Select All That Apply (SATA): When reviewing a drug to be given, the nurse notes that the drug is excreted in the urine. What points should be included in the nurse’s assessment of the patient?
a.The patient’s liver function tests
b.The patient’s bladder tone
c.The patient’s renal function tests
d.The patient’s fluid intake
e.Other drugs being taken that could affect the kidney
f.The patient’s intake and output for the day
c) renal functioning
d) fluid intake
e) other drugs being taken that could affect kidneys
- SATA: When considering the pharmacokinetics of a drug, what points would the nurse need to consider?
a.How the drug will be absorbed
b.The way the drug affects the body
c.Receptor site activation and suppression
d.How the drug will be excreted
e.How the drug will be metabolized
f.The half-life of the drug
a) how drug is Absorbed
d) how drug is Excreted
e) how drug is Metabolized
f) half-life (Distribution)
*remember pharmacokinetics is ADME!
- SATA: Drug–drug interactions are important considerations in clinical practice. When evaluating a patient for potential drug–drug interactions, what would the nurse expect to address?
a.Bizarre drug effects on the body
b.The need to adjust drug dose or timing of administration
c.The need for more drugs to balance the effects of the drugs being given
d.A new therapeutic effect not encountered with either drug alone
e.Increased adverse effects
f.The use of herbal or alternative therapies
b) adjust dose or timing of administration
e) increased adverse effects
f) use of herbal or alt therapies
