Note: Read the questions: the questions only have one answer unless the question specifically
states there is more than one correct answer.
ANSWERED SO FAR
Understand what a prodrug is, and activation/inactivation by
...
Note: Read the questions: the questions only have one answer unless the question specifically
states there is more than one correct answer.
ANSWERED SO FAR
Understand what a prodrug is, and activation/inactivation by liver enzymes, and
how it differs from active drugs.
The liver is the principal site of drug metabolism. Although metabolism typically inactivates
drugs, some drug metabolites are pharmacologically active—sometimes even more so than the
parent compound. An inactive or weakly active substance that has an active metabolite is called a
prodrug, especially if designed to deliver the active moiety more effectively.
Know what Bioavailability (BA)
a term used in pharmacology and nutritional and environmental sciences. In
pharmacology, it refers to the degree and rate at which an administered drug is absorbed
by the body's circulatory system, the systemic circulation. Bioavailability is an essential
measurement tool since it determines the correct dosage for non-intravenous
administration of a drug availability means
Bioavailability. In pharmacology, bioavailability (BA or F ) is a subcategory of
absorption and is the fraction of an administered dose of unchanged drug that reaches
the systemic circulation
Bioavailability is affected by chemical instability, solubility and first-pass
metabolism
The first pass effect- is a phenomenon of drug metabolism whereby the concentration
of a drug is greatly reduced before it reaches the systemic circulation. It is the fraction
of drug lost during the process of absorption which is generally related to the liver and
gut wall.
Bioequivalence does not affect bioavailability
Bioequivalence is the similarity of two drugs that share the same desired outcome for
patients. Pharmaceutical equivalence means two drugs release the active ingredient into
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the bloodstream at the same amount and same rate. When assessing how well a generic
drug works, scientists evaluate its bioequivalence to the name-brand version.
Understand what the Cytochrome P450 system is in the liver
Cytochrome P450 enzymes are primarily found in liver cells but are also located in
cells throughout the body. ... Cytochrome P450 enzymes account for 70 percent to 80
percent of enzymes involved in drug metabolism. Cytochrome P450 enzymes also
function to metabolize potentially toxic compounds, including drugs and products of
endogenous metabolism such as bilirubin, principally in the liver.
Clopidogrel (Plavix) is a prodrug and must be activated by hepatic CYP2C19 metabolism;
individuals who are poor metabolizers may not form the active metabolite and have reduced
antiplatelet response.
A drug’s half-life determines how often the drug is administered?
The elimination half-life of a drug is a pharmacokinetic parameter that is defined
as the time it takes for the concentration of the drug in the plasma or the total
amount in the body to be reduced by 50%. In other words, after one half-life, the
concentration of the drug in the body will be half of the starting dose.
Steady state of a drug is reached in approximately 5 to 6 times the half-life
Inhalation, oral and parenteral drug action and onset of effects?
Inhalational administration can be used. The lungs serve as an effective route of
administration of drugs. The pulmonary alveoli represent a large surface and a minimal
barrier to diffusion. The lungs also receive the total cardiac output as blood flow. Thus,
absorption from the lungs can be very rapid and complete.
Bioavailability of drugs administered orally varies greatly.
Parenteral administration refers to any routes of administration
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