Finals Mod 6-9 Flashcards
established to provide
- correct plasma level w/o excessive
fluctuation
- drug accumulation outside the therapeutic window.
Dosage Regimen
Calculating multiple-dose regimen, –> desired/target plasma drug concentration, related to therapeutic response,
multiple-dose regimen must be designed to produce plasma concentrations outside the therapeutic window.
T or F
False
within the therapeutic window
Two Parameters that can be adjusted in developing a dosage regimen?
size of the drug dose & frequency of the drug administration.
initial bolus of a drug is used to obtain desired concentration as rapidly as possible.
LOADING DOSE
Therefore, if an IV loading dose of R/k is given, followed by an IV infusion, steady state
plasma drug concentration is obtained immediately and maintained.
T or F
T
Since extravascular doses require time for absorption into the plasma to occur,
therapeutic effects are delayed until sufficient plasma concentrations are achieved.
T or F
T
To reduce the onset time of the drug-that is, the time it takes to achieve the minimum
effective concentration-a ______ is given.
loading dose (priming) or initial dose of drug
main objective: to achieve desired plasma concentrations as quickly as possible.
Thereafter, a maintenance dose is given to maintain plasma drug concentration.
Intravascular Loading Dose
General Rule: if a drug is normally excreted via the kidneys, its maintenance dose will
need not to be adjusted in patients with renal impairment.
T or F
F
need to
the maintenance rate [mg/h] of drug administered equal to the rate of elimination at steady state.
maintenance dose
- Decrease the dosing interval, dose remains unchanged. Increase the dose, the dosing interval remains unchanged.
T or F
F
Increase…Decrease
The objective is to produce a plasma profile which approaches that normally
achieved in the absence of renal failure.
T or F
T
also defined as the amount of drug required to keep a desired mean steady state concentration in the tissues. It is administered after L.D.
The required ______ may be calculated as: MD = CpCL /F
maintenance dose
It is based on the principle that for some drugs there is a close relationship between the
plasma level of the drug and its clinical effect.
Therapeutic Drug Monitoring
The clinical value of plasma level monitoring depends on how precisely the treatment
outcome can be defined. When a precise therapeutic end point is difficult to define, monitoring of drug levels may be of considerable therapeutic assistance.
T or F
T
Drugs for which relationship between dose and plasma concentration is unpredictable?
Phenytoin
Drugs with a narrow therapeutic window?
Lithium, phenytoin, and digoxin
Drugs with steep dose response curve?
theophylline
Drug with saturable metabolism?
Phenytoin
Drug with poorly defined end point or difficult to clinically predict the response?
immunosuppressant drugs
drug alters the relationship between dose & plasma concentration?
plasma concentration of lithium is increased by thiazide.
It is relative amount of drug from an administered dosage form which
enters the systemic circulation and rate at which the drug appears in the systemic circulation.
Bioavailability (BA)
The extent and rate at which its active moiety is delivered from pharmaceutical form and
becomes available in the systemic circulation
Bioavailability (BA)
4 Possible differences –> Bioinequivalence:
-drug particles size
-excipients
-manufacturing equipment/process
-site of manufacture
Two products are bioequivalent if
➢ They are pharmaceutically equivalent
➢ Bioavailabilities (both rate and extent) after administration in the same molar dose are different to such a degree that their effects can be expected to be essentially the same
T or F
F
similar
THERAPEUTIC EQUIVALENCE:
Two products are therapeutically equivalent if:
➢ Pharmaceutically equivalent
➢ efficacy and safety will be essentially the same as derived from appropriate studies.
T or F
T
Studies involved in therapeutic equivalence:
◦ bioequivalence studies
◦ pharmacodynamic studies
◦ clinical studies
◦ in vitro studies
Original Drug NDA Requirements:
a. Chemistry
b. Manufacturing
c. Controls
d. Labeling
e. Testing
f. Animal Studies
g. Clinical Studies (Bioavailability/Bioequivalence)
Generic Drug ANDA Requirements:
a. Chemistry
b. Manufacturing
c. Controls
d. Labeling
e. Testing
f. Bioequivalence Study (In Vivo, In vitro)
Generic drug applications are termed “_______” because they are generally not required to include preclinical (animal) and clinical (human) data to establish safety and effectiveness.
Instead, generic applicants must scientifically demonstrate that their product is
bioequivalent (i.e., performs in the same manner as the original; drug).
abbreviated
Is an essential pharmacokinetic process, which render lipid soluble and nonpolar compounds to water soluble and polar compounds so that they are excreted by various process from the body.
METABOLISM
It is a specific term used for the chemical transformation of xenobiotics in the living organisms.
Biotransformation
METABOLISM render water soluble and polar compounds to lipid soluble and nonpolar compounds so that they are excreted.
T or F
F
render lipid soluble and nonpolar compounds to water soluble and polar compounds
These are all chemical substances that are not nutrient for the body (foreign body) and which enter the body through ingestion, inhalation or dermal exposure.
Xenobiotics
Drug Metabolism
* Most organic compounds entering the body are relatively water soluble (hydrophilic).
* To be absorbed, they must traverse the lipoprotein membranes of the ______ walls of the gastrointestinal (GI) tract.
T or F
F…..lumen
lipid soluble (lipophilic).
Because of ________, lipophilic compounds are not excreted to any substantial extent in the urine.
reabsorption in the renal tubules
Thus, the formation of water-soluble metabolites not only enhances drug elimination, but also leads to compounds that are generally pharmacologically inactive and relatively nontoxic.
T or F
T
If lipophilic drugs, or xenobiotics, were not metabolized to polar, readily excretable water-
soluble products, they would remain indefinitely in the body, eliciting their biological effects.
T or F
T
Consequently, drug metabolism reactions have traditionally been regarded as detoxication (or detoxification) processes. Therefore, it is assumed that drug metabolism reactions are always detoxifying.
T or F
F
not all drug metabolism reactions are always detoxifying.
substances that result from metabolism?
It may be inactive, or they may be similar to or different from the original drug in therapeutic activity or toxicity.
metabolites
FACTORS INFLUENCING DRUG METABOLISM:
Physicochemical properties of the drug
Chemical factors
Biological factors
the parent compound is inactive when administered and must be metabolically converted to a biologically active drug (metabolite), these types of
compounds are referred to as ____?
Prodrugs
The biochemical alteration of drug or xenobiotic in the presence of various enzymes that acts as a catalyst which themselves not consumed in the reaction and thereby may activate or deactivate the drug is called ________
biotransformation
Active to Inactive:
Phenobarbitone→Hydroxyphenobarbitone