Study Set Content:
dose of drugs required to produce the
desired effects to that which produces an undesired effect.
Therapeutic index
The therapeutic index of a drug in humans is almost never known
with
real precision;
The therapeutic index of a drug in humans is almost never known
with real precision; instead, drug trials and accumulated clinical
experience often reveals a range of usually (blank)and a
different (but sometimes overlapping) range of possibly toxic dose
effective doses
the range between the minimum
toxic dose and the minimum therapeutic dose.
Therapeutic Window
indicates the maximal
efficacy of a drug
The Graded Dose-Response curve
indicates the potential
variability of responsiveness among individuals.
The Quantal dose-effect Curve
VARIATION IN DRUG RESPONSIVENESS
Individuals exhibit an unusual or idiosyncratic drug
response.
Hyporeactive or Hyperreactive
Tolerance to the drug's effect
Tachyphylaxis
One that is infrequently observed in most patients.
Individuals exhibit an unusual or idiosyncratic drug response
The intensity of the effect of a given dose of the drug is
diminished or increased compared with the effect was
seen in most individuals.
Hyporeactive or Hyperreactive
When responsiveness diminishes rapidly after
administration of a drug.
Tachyphylaxis
Responsiveness usually decreases as a consequence of
continued drug administration, producing a state of
relative tolerance to the effects of the drug.
Tolerance to the drug's effect
may contribute to variation in drug
responsiveness among patients or within an individual patient at
different times.
Four general mechanisms
such pharmacokinetic differences may alter the clinical
response.
Alteration in Concentration of Drug that Reaches the
Receptor
This mechanism contributes greatly to variability in responses to
pharmacologic antagonists.
Variation in Concentration of an Endogenous
Receptor Ligand
Thus, propranolol, a β-adrenoceptor antagonist, markedly
endogenous catecholamines are elevated (as in
pheochromocytoma)
Thus, propranolol, a β-adrenoceptor antagonist, markedly
endogenous catecholamines are elevated (as in
pheochromocytoma) but do not affect the resisting heart rate of a
well-trained marathon runner.
Experimental studies have documented changes in drug response
caused by increases or decreases in the number of receptors sites
or but alteration in the efficiency of coupling of receptors to distal
effector mechanism.
Alteration in Number or Function of Receptors
In some cases, the changes in the receptor is caused by
other hormones
For example, (blank) increases both the number of β
receptors, in rat heart muscle and cardiac sensitivity.
hyroid hormone
can result for the
opposite reason when the administration of an agonist is
discontinued.
Potentially disastrous withdrawal symptoms
