FTM 52-53 - Pharmacokinetics 1 & 2 Flashcards
What are the four mechanisms of drug permeation.
Define pharmacokinetics and pharmacodynamics.
Pharmacokinetics - the branch of pharmacology concerned with the movement of drugs in the body.
Parmacodynamics - the branch of pharmacology concerned with the effects of drugs and the mechanism of their action.
Define absorption as it applies to pharmacology.
Aborption - transfer of a drug from its site of administration to the blood stream
Define bioavailability
The proportion of a drug or other substance that enters the circulation when introduced into the body and so is able to have an active effect.
What drug delivery method allows for complete absorption of that drug?
IV administration
What is the first-pass effect?
When a drug is taken orally a fraction of the drug is metabolized in the gut wall and liver before reaching systemic circulation.
Define an enteral route. What are the three enteral routes of drug administration?
Enteral - involving or passing through the GI tract, either orally, sublingually, or rectally
Which enteral routes of drug administration can avoid the first-pass effect at least partially.
Sublingual (complete bypass)
Rectal (partial avoidance)
What are the parenteral routes of administration we need to know?
IV
Intramuscular
Subcutaneous
Intradermal
Oral/Nasal Inhalation
Topical
Transdermal
What are the 5 major factors that influence drug absorption
Which forms of the weak acids and bases can cross a plasma membrane?
Weak acids in the protonated form are uncharged and can pass through plasma membranes.
Weak bases in the unprotonated form are uncharged and can pass through the plasma membranes.
What is the Henderson-Hasselbalch equation?
pH = pKa + log [A-/HA]
As it pertains to pharmacology, what is the most important application of the henderson-hasselbalch equation?
Ion trapping which is the concept that if a drug is in its liposoluble form during its passage down a renal tubule, a significant fraction will be reabsorbed by passive diffusion.
Weak acids are exreteded faster in ________ urine; while weak bases are excreted faster in ________ urine.
Alkaline
Acidic
Where are drugs absorbed fastest in the GI tract? Why? What can speed up the absorption of a drug in the GI tract?
There is also increased blood flow to the small intestine
What is P-gp and what does it do? What are some other names for it? Where is it commonly found?
P-glycoprotein or multi-drug resistance protein-1 (MDR1) is a transmembrane transporter that pumps many different drugs (and other toxins) out of cells. It is common on the intestinal epithelium where it pumps these substances into the gut lumen.
How can the bioavailability of a drug administered using a particular route be determined?
What does the AUC of a plasma concentration vs time graph represent?
It reflects the extent of absorption of that drug
As it pertains to drugs, what does the term “distribution” refer to?
The process by which a drug leaves the blood stream and enters the ECF and/or the cells of the tissues.
What are the key factors affecting drug distribution?
Which organs are drugs usually distributed to faster and which organs experience slower distribution?
What plasma proteins do acidic and basic drugs bind to? Can any of these drugs take effect while bound?
What are the four ways drug biotransformation can alter drugs?
What type of reaction is a phase-II drug metabolism reaction?
What is the most abundant CYP450 enzyme found in the liver? About what percentage of drugs does this isoform metabolize?
How is P450 activity typically increased? Which drugs can do this?
What are the dangers of CYP450 induction?
What are the three types of genetic variations that can influence pharmacotherapy?
What are the three basic processes involved in renal excretion of drugs?
