Term
| Volume of Distribution (Vd) |
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Definition
| When the drug is distributed into all of the tissues that it is physically able to penetrate. |
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Term
Water-soluble drugs
(Volume of Distribution) |
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Definition
| Low Vd; higher serum levels |
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Term
Lipid-soluble drugs
(Volume of Distribution) |
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Definition
| High Vd; lower serum levels |
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Term
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Definition
Blood-brain barrier
Prevents passage from blood to brain tissue
Drugs that cross
Lipid soluble
Transport system
Anesthetic agents, ethanol, some steroids, and some sedative-hypnotic agents |
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Term
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Definition
~Bound drug (pharmacologically inactive)
Proteins serve as reservoirs
~Unbound drug (produce effect)
~Binding is reversible |
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Term
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Definition
~How the body changes the chemical structure of a drug.
~Sites of metabolism
Liver (major site)
GI tract, lungs, skin, and kidneys
~Body attempts to neutralize or detoxify the substance. |
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Term
Biotransformation
(Metabolism) |
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Definition
| Outcome of the metabolic processes |
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Term
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Definition
| Resulting chemical from converted drug |
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Term
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Definition
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Term
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Definition
Contain enzymes to transform drugs
(Parenchyma Contain millions of hepatocytes) |
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Term
P-450 Enzyme System
(Hepatic Microsomal Enzyme System) |
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Definition
Metabolism of endogenous and exogenous substances
Drugs can induce or inhibit synthesis of isoenzymes |
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Term
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Definition
A drug that increases the amount or activity of the isoenzyme.
Metabolism occurs more rapidly
Decrease in substrate drugs
Induce/Reduce |
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Term
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Definition
| Drugs that are metabolized by a specific isoenzyme |
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Term
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Definition
A drug that decreases the activity of the isoenzyme.
Metabolism is decreased
Increase in substrate drug
Inhibit/Increase |
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Term
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Definition
Drug metabolized before distribution
Route of administration: Oral
Drug crosses directly into hepatic portal circulation
Some drugs can be completely inactivated |
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Term
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Definition
| Removal of a drug from the body |
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Term
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Definition
Kidneys
Liver, GI tract, lungs, sweat and salivary glands, skin, and breast milk |
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Term
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Definition
Rate of disappearance of the drug
Slow clearance
High clearance |
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Term
Glomerular Filtration
(Renal Excretion) |
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Definition
Low-molecular-weight molecules pass through the glomeruli
Free (unbound) drugs will appear in the filtrate |
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Term
Passive Tubular Reabsorption
(Renal Excretion) |
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Definition
Concentration gradient: higher concentration to lower concentration
Must be lipophilic to be reabsorbed |
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Term
Tubular Secretion
(Renal Excretion) |
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Definition
Active process
Occurs in proximal tubule
Dependent on active carriers |
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Term
Renal Excretion
(Factors that Affect ) |
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Definition
pH of urine
Acid drugs in basic environment: ionize
Basic drugs in acidic environment: ionize
Drug will not be reabsorbed
Excretion increased |
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Term
Renal Excretion
(Factors that Affect ) |
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Definition
Overuse of active transport system
Two drugs rely on the same transport system for tubular secretion
Excretion decreased |
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Term
Biliary Excretion
(Factors that Affect ) |
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Definition
Enterohepatic recirculation
Bile reabsorbed
Excretion decreased |
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Term
Respiratory Excretion
(Factors that Affect ) |
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Definition
~Respiratory activity
Faster respiratory rate increases excretion
~Blood flow to lungs
Increased blood flow increases excretion |
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Term
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Definition
Most drugs combine with receptors to produce their effects
Receptor
Specialized area on the cell wall
Drug + Receptor → Drug-receptor (binding) = Response
Receptor subtypes
“fine-tuning” of pharmacology |
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