KEY TERMS PHAR 100:
AGONIST- drugs that bind to and stimulate a receptor
ANTAGONIST- drugs that bind to but block the response at a receptor
THERAPEUTIC RANGE- range of plasma concentration where the drug is effective, but toxicities usually do
not occur
BIOAVAILABILITY- the fraction of an administered dose that reaches the systemic circulation (blood) in an
unchanged form (a drug is considered 100% bioavailable when injected because it does not require
absorption)
BIOTRANSFORMATION- (drug metabolism) is the conversion of a drug to a different chemical compound.
The products are called metabolites.
HALF-LIFE- half-life of a drug is the time needed for the liver and kidney to remove half the drug from the
body.
ADVERSE EFFECT- any effect produced by a drug in a patient that is not the intended effect
TOLERANCE- a state in which repeated administration of a given dose of a drug has progressively less
pharmacological effect or a state in which the dose of a drug must be increased to obtain the same
magnitude of pharmacological effect as was produced by the original dose.
DEPENDENCE- abnormal physiological state produced by repeated administration of a drug that leads to
the appearance of a withdrawal syndrome when drug administration is discontinued, or the dose is
decreased.
ADDICTION- a state in which stopping or abruptly reducing the dose of a given drug produces non-physical
symptoms. More difficult to treat than dependence
, DRUGS- any substance received by a biological system that is not received for nutritive purposes, and
which influences the biological function of the organism. This broad definition means that chemicals,
biological agents, and herbal products are all considered drugs.
THERAPEUTIC RANGE- drug toxicity is assessed using a measure called the therapeutic index, which is
calculated by this formula: TD50/ED50 where TD50 is the toxic dose in 50% of the population and ED is the
effective dose in 50% of the population
High potency is often considered desirable because less drug is available to cause adverse effects.
Drugs that are highly potent require only small doses to achieve their effects.
3 ways of administration of a drug:
1. Topical (skin)
- Bypasses enzymes
- Convenient
- Expensive
- Inhalation (avoids toxicity unlike with oral)
2. Enteral
- Most convenient (Mouth)
- Enter the blood through the GI tractliver contains enzymes that decrease the amount of
active drug left to enter the general circulation (First pass effect)
- Rectum: digestive enzymes of the stomach and intestine are bypassed
AGONIST- drugs that bind to and stimulate a receptor
ANTAGONIST- drugs that bind to but block the response at a receptor
THERAPEUTIC RANGE- range of plasma concentration where the drug is effective, but toxicities usually do
not occur
BIOAVAILABILITY- the fraction of an administered dose that reaches the systemic circulation (blood) in an
unchanged form (a drug is considered 100% bioavailable when injected because it does not require
absorption)
BIOTRANSFORMATION- (drug metabolism) is the conversion of a drug to a different chemical compound.
The products are called metabolites.
HALF-LIFE- half-life of a drug is the time needed for the liver and kidney to remove half the drug from the
body.
ADVERSE EFFECT- any effect produced by a drug in a patient that is not the intended effect
TOLERANCE- a state in which repeated administration of a given dose of a drug has progressively less
pharmacological effect or a state in which the dose of a drug must be increased to obtain the same
magnitude of pharmacological effect as was produced by the original dose.
DEPENDENCE- abnormal physiological state produced by repeated administration of a drug that leads to
the appearance of a withdrawal syndrome when drug administration is discontinued, or the dose is
decreased.
ADDICTION- a state in which stopping or abruptly reducing the dose of a given drug produces non-physical
symptoms. More difficult to treat than dependence
, DRUGS- any substance received by a biological system that is not received for nutritive purposes, and
which influences the biological function of the organism. This broad definition means that chemicals,
biological agents, and herbal products are all considered drugs.
THERAPEUTIC RANGE- drug toxicity is assessed using a measure called the therapeutic index, which is
calculated by this formula: TD50/ED50 where TD50 is the toxic dose in 50% of the population and ED is the
effective dose in 50% of the population
High potency is often considered desirable because less drug is available to cause adverse effects.
Drugs that are highly potent require only small doses to achieve their effects.
3 ways of administration of a drug:
1. Topical (skin)
- Bypasses enzymes
- Convenient
- Expensive
- Inhalation (avoids toxicity unlike with oral)
2. Enteral
- Most convenient (Mouth)
- Enter the blood through the GI tractliver contains enzymes that decrease the amount of
active drug left to enter the general circulation (First pass effect)
- Rectum: digestive enzymes of the stomach and intestine are bypassed
