MN553 Advanced Pharmacology & Pharmacotherapeutics Unit 2 Quiz Study Guide
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Describe the absorption, distribution, metabolism, and elimination process
of drugs in the body.
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Absorption: entering the body
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Parenteral Administration (IV): straight to the bloodstream, but once
administered, the drug absorption cannot be slowed, and the drug
cannot be removed from the body
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Oral: common and most convenient route, keep in mind pH and where
the drug needs to take effect (stomach, intestines, etc.)
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Site of administration: eyes, ears, throat/lungs, skin
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Bioavailability: Not all of the administered dose may be dissolved,
absorbed, or survive liver metabolism, only a fraction of an administered
dose makes it to the bloodstream. 100% bioavailability for IV, 10-90% for
oral.
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Peak Blood Levels: Rapid absorption leads to higher peak blood levels,
with a risk of greater toxicity and side effects. Some drugs (like
aminoglycoside antibiotics) need to be closely monitored for toxicity.
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Distribution: process of drug moving through the body
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Properties that affect distribution: drug size, charge, chemical structure,
pH, molecular size, lipid or water solubility.
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Henderson–Hasselbalch Relationship: the effects of pH and ion
charge/concentration affecting how drugs pass through cell membranes
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Protein binding: the biggest player is albumin.
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Other proteins: alpha-1-acid glycoprotein, cortisol-binding globulin, sex
hormone–binding globulin, and lipoproteins.
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General principle that drug action occurs through free, unbound drug.
Protein binding, which may include binding to proteins that are not in the
plasma, also prevents the interaction of drug molecules with their site of
action. Plasma protein binding creates a reservoir of bound drug
molecules that can dissociate at any time to interact with drug receptors
and produce responses.
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Transport system: membrane proteins that actively move drugs in and out
of the cell.
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Volume of Distribution: the concentration of a drug can vary depending
on where it “sits” in the body’s fluids (plasma, extracellular fluid or
intracellular fluid).
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Metabolism: the chemical alteration of the drugs into metabolites.
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Metabolism of drugs can occur in every biological tissue, but it occurs
mostly in the smooth endoplasmic reticulum of cells in the liver.
