Introduction to Pharmacology - Terminology and drug classification Flashcards
The ebers papyrus contains ____ prescriptions/ dosages.
800
What is the famous saying by Theophrastus Bombastus von Hohenheim?
All drugs are poison, Proper dose is what separates remedy from poison.
What are the 4 principles of pharmacokenetics?
ADME
Absorption, Distribution, Metabolism, Excretion
What is being looked at in pharmacodynamics?
Cell/tissue response / involved receptors.
What is being looked at in the study of pharmacogenetics?
How genetics affect drugs/ therapies.
What is a drug?
A drug is a molecule that interacts with specific molecular components of an organism to produce biochemical and physiologic changes/effects
What are most drugs classified as?
Synthetic drugs
What are the three ways to name a drug?
Chemical name: IUPAC
Generic name (non proprietary)
Trade or proprietary name
What is the purpose of drug therapy?
To induce a desired pharmacological response.
What determines the degree of pharmacological response?
For the most drugs the degree of the pharmacologic response is related to the drug concentration at the tissue (receptor)
What does a drug cross from its site of administration to reach its site of action?
o A drug crosses several lipoidal membrane barriers from its site of administration to reach its
site of action
The processes that govern movement of drugs across lipid based biological membranes are important because?
The processes that govern the movement of drugs across lipid-based biological membranes are important and regulate its absorption, distribution and excretion from the animal
What are the 4 mechanisms by which drugs move through the body?
- ) Bulk Flow
- ) Passive diffusion
- ) Carrier mediated transport
- ) Endocytosis/ pinocytosis
What are the 2 major mechanisms/ most important for drugs to move through the body?
- ) Bulk Flow
2. ) Passive diffusion
How does bulk flow move drugs through the body?
Movement across the fenestrated capillaries of the body from plasma to tissue
What bulk flow dependent on to move drugs from plasma or tissue fluid? Does chemical nature affect this?
Is dependent on the concentration of drug dissolved in the plasma or tissue fluid
Chemical nature does not affect this.
If you have an increase in concentration of a drug, you will have ____ diffusion via bulk flow
Easier
What is passive diffusion?
Transmembrane diffusion. Uses channels for water soluble drug, and lipid soluble will dissolve through the membrane
What factors influence passive diffusion of a drug across cell membranes?
- Lipid solubility of the drug
- Environmental pH
- Surface area
- Thickness of the membrane to be traversed (edematous V/S normal tissues)
- Concentration of diffusible drug
What method is the most common way that compounds move through the body?
Passive diffusion is the most common method by which compounds move through the body
How does molecular weight of a compound affect passive diffusion?
Smaller weight diffuses easier.
What is your partition coefficient?
Ratio determined by mixing drug in combo of water and organic solvent.
It will characterize the relative oil versus water affinity of a compound when it exists in its unionized form and Predict the ability of a drug to pass through cell membrane
What does it mean if a partition coefficient has a ratio greater than 1?
increased lipid solubility and increased distribution.
What kind of pH would a drug like?
like likes like
When would a drug be more nonionized?
A drug will be more nonionized and more likely to diffuse into tissues when present in a “like” environment.
Drugs will be trapped by ionization when present in an “unlike” environment
Weak acids are better absorbed in…
Weak bases are poorly absorbed in …
acidic conditions
acidic conditions
Weak bases are better absorbed in…
Weak acids are poorly absorbed in …
alkaline conditions
alkaline conditions
What part of the body is better to absorb a weak acid? A weak base?
stomach
gut
What is carrier mediated transports?
Transport of drugs across the membrane via special carriers and receptors.
Which drugs use carrier transports?
Non lipophillic drugs. This helps them to cross the membrane, since they cant really do it on their own.
Does The laws of diffusion and ph partitioning govern transmembrane flux of drugs?
No
What are the types of carrier mediated transport?
- Facilitated diffusion ( passive transport (nonactive) (piggy back))
- Active transport
What are carrier mediated transporters important for?
- GI transmission of nutrients/ drugs.
- Cellular uptake (glucose)
- Removal of drugs from CSF, Biliary and renal excretion of drugs.
How does active transport work?
- Drug transport is conducted by specific carrier proteins through the membrane
• It requires cellular energy to move a drug against its concentration gradient. Energy is driven by the hidrolysis of adenosine triphosphate (ATP) - This can move drugs in either direction to absorb or remove a drug.
What is P-Glycoprotien?
- Often referred to as multidrug resistance protein MDR1 • ATP- driven efflux transporter (ABC transporter)
- Encoded by the multidrug-resistance gene MDR1/ABCB1
Where is MDR1 expressed?
• MDR1 is highly expressed at the blood-brain barrier, at the blood-testis
barrier and also in kidney, liver, intestine and placenta
What is the goal of MDR1?
Protective. Keeps exogenous compounds out of critical tissues.
What is endocytosis or pinocytosis?
A compound binds to the surface of the membrane. The membrane invaginates
and interiorizes the compound
Is endocytosis or pinocytosis a primary mechanism of transmembrane passage for most theraputic drugs?
• This is not a primary mechanism of transmembrane passage for most
therapeutics drugs
