General, pharmacokinetics Flashcards
• The most important properties of an ideal drug are 1. ______ 2.______3.______.
effectiveness, safety, and selectivity.
• If a drug is not ______, it should not be used.
effective
• There is no such thing as a ____ drug: All drugs can cause _____
safe, harm
• There is no such thing as a _____drug: All drugs can cause ___ _____.
selective, side effects
• The objective of drug therapy is to provide _____ with ______.
maximum benefit , minimum harm.
• Because all patients are unique, drug therapy must be _____ to each individual.
tailored
• Drugs have three types of names: a _____name, a _____or _____ name, and a _____or_____name.
chemical
generic or nonproprietary
trade or proprietary
• Each drug has only _____ generic name but can have many _____names.
one
trade
• Generic names facilitate _____ and therefore are good.
communication
Trade names _____ communication and should be outlawed.
confuse
•________ drugs are defined as drugs that can be purchased without a prescription.
Over-the-counter (OTC)
• Because the job of the drug representative is _____ and not _____, this person may not be your best source of drug information—especially if you are trying to establish an _____ _____ between the representative’s product and a drug from a competing manufacturer.
sales
education
information
unbiased comparison
• Pharmacokinetics consist of four basic processes: _______, _____, _____ and _____
- absorption
- distribution
- metabolism
- excretion
• Pharmacokinetic processes determine the_____ of a drug at its _____ of _____, and thereby determine the _____ and _____ _____ of responses.
concentration
sites of action
intensity
time course
• Pharmacokinetics consist of four basic processes: _____,_____,_____ and _____.
absorption, distribution, metabolism, and excretion.
• To move around the body, drugs must cross membranes, either by _____,_____ and _____.
(1) passing through pores, (2) undergoing transport, or (3) penetrating the membrane directly.
• ______—found in the liver, kidney, placenta, intestine, and brain capillaries—can transport a variety of drugs out of _____.
P-glycoprotein
cells
• To cross membranes, most drugs must dissolve directly into the _____ of the membrane.
lipid bilayer
Accordingly, _____ drugs can cross membranes easily, whereas drugs that are _____or _____ cannot.
lipid-soluble
polar or ionized
• Acidic drugs ionize in _____, whereas basic drugs ionize in _____ _____.
basic (alkaline) media
acidic media
• Absorption is defined as
the movement of a drug from its site of administration into the blood.
• Absorption is enhanced by
rapid drug dissolution, high lipid solubility of the drug, a large surface area for absorption, and high blood flow at the site of administration.
: rapid onset, precise control over the amount of drug entering the blood, suitability for use with large volumes of fluid, and suitability for irritant drugs.
• Intravenous administration has several advantages
• Intravenous administration has several disadvantages:
high cost; difficulty; inconvenience; danger because of irreversibility; and the potential for fluid overload, infection, and embolism.
• Intramuscular administration has two advantages:
suitability for insoluble drugs and suitability for depot preparations.
• Intramuscular administration has two disadvantages:
: inconvenience and the potential for discomfort
• Subcutaneous administration has the same advantages and disadvantages as ________
IM administration.
• Oral administration has the advantages of _____,_____ and _____.
ease, convenience, economy, and safety.
• **The principal disadvantages of oral administration are high _______________________________ (because oral drugs must pass through the liver before reaching the general circulation).
variability and possible inactivation by stomach acid, digestive enzymes, and liver enzymes
• **Enteric-coated oral formulations are designed to release their contents in the ____________.
small intestine—not in the stomach.
•**Sustained-release oral formulations are designed to release their contents_____, thereby permitting a _____ _____ between doses.
slowly
longer interval
** Distribution is defined as _______.
the movement of drugs throughout the body.
•** In most tissues, drugs can easily leave the _____ through spaces between the _____ that compose the _____.
vasculature
cells
capillary wall.
Refers to the presence of tight junctions between the cells that compose capillary walls in the central nervous system - CNS
Blood brain barrier
Because of this barrier, drugs must pass through the cells of the capillary wall rather than between them in order to reach the CNS.
Blood brain barrier
Does not constitute an absolute barrier to the passage of drugs
The membranes of the placenta
The same factors that determine drug movements across all other membranes determine the movement of drugs across the
Placenta
Many drugs that bind reversible to plasma _____.
While bound to this substance, drug molecules cannot _____the vascular system.
Albumin
leave
Defined as the enzymatic alteration of drug structure
Drug metabolism or Bio transformation
Most drug metabolism takes place in the_____.
It is catalyzed by the but the APRN and_____ _____ system of the enzymes.
Liver
cytochrome P 450
Promotion of renal drug excretion by converting lipid soluble drugs into more polar forms
The most important consequence of drug metabolism
Other consequences of drug metabolism are:
Conversion of drugs to_____ _____ forms.
Conversion of drugs to more_____forms.
Conversion of pro drugs to their_____forms.
Conversion of drugs two more_____or less_____
Less active or inactive Active Active Toxic Toxic
Some drugs can induce or stimulate synthesis of hepatic _____ _____ _____.
They can accelerate their own_____and the_____of other drugs.
Drug metabolizing enzymes
Metabolism
Metabolism
The rapid inactivation of some oral drugs as a pass through the liver after being absorbed
First-pass effect
Most drugs are excreted by the
Kidneys
glomerular filtration
Passive tubular reabsorption
Active tubular secretion
The three steps to renal drug excretion
_________________________________________Undergo extensive passive reabsorption back into the blood and therefore cannot be excreted by the kidneys until they are converted two more polar forms by the__________.
Drugs that are highly lipid soluble
Liver
Drugs can be excreted into_____ _____, thereby posing a threat to the nursing infant
Breast milk
Define …… The plasma drug level below which therapeutic effects will not occur.
The minimum effective concentration MEC.
The therapeutic range of a drug lies between the____and the____ _____.
MEC
Toxic concentration
Drugs with A _____therapeutic range are relatively easy to use safely.
Wide
Drugs with a____therapeutic range are difficult to use safely.
Narrow
Defined as the time required for the amount of drug in the body to declined by 50%
The half life of a drug
Drugs that have a short_____must be administered more frequently than drugs that have a_____half life
Half life
Long
When drugs are administered repeatedly their levels will gradually_____and then reach a steady Plauteau
Rise
The time required to reach Plauteau is equivalent to about_____half lives.
Four
If plasma drive levels fluctuate too much between doses, the fluctuating ends could be reduced by
Getting smaller doses and shorter intervals while keeping the total daily dose the same
Using a continuous infusion
Using a depot preparation
It may be necessary to use a loading those to achieve Plauteau quickly if you have a
Drug with a long half life
When drug administration is discontinued, most or 94% of the drug in the body will be eliminated over
Four half lives
