Assigned to a drug when it is found to be of demonstrated or potential therapeutic usefulness.
New drugs are given names by the United States Adopted Name (USAN) Council
The generic name informs you of the drug's identity without drug company boundaries - providing different names for the same drugs
Using generic names is the most convenient and precise way to discuss drugs in the context of every day.
What is the proprietary (trade) name?
Selected by the pharmaceutical company to market the drug.
Trade names are sometimes chosen to reflect the activity of the drug. - Lopressor for antihypertensive.
What is the problem with trade names?
Different trade names often apply to the same drug - each company may market the drug under its own trade name once patent rights have been expired.
Similarities of names for drugs used for different purposes or effects --> confusion of the names can lead to serious consequences if the wrong drug is given.
Define the site of drug action
Part of the body (organ/cell/tissue) where drug acts to start a chain of events leading to an effect.
Define mechanism of drug action
The means by which the presence of a drug produces an alteration in function.
Most drugs show selectivity and specificity in their action.
Drugs act extracellular and cellular (inc. intracellular sites
Many drugs need to combine with receptors to produce an effect
How do drugs work?
They do not do new things - they simply modify (increase or decrease) what is already there.
They mimic or block actions of endogenous compounds.
What does an agonist do?
What does an antagonist do?
Why is it important to know the optimal way of administering drugs?
Knowing the relationship between dose, drug concentration, and drug effects allows clinicians to develop appropriate treatments.
A rational approach to achieving beneficial effects with minimal adverse effects combines the principles of pharmacokinetics with pharmacodynamics.
The interplay of pharmacodynamics and pharmacokinetics..
What body does to a drug.
Determines the relationship between the dose of a drug and the concentration of drug in blood as a function of time: Dose concentration effect.
Determines how long the drug will appear at its target organ.
What drug does to body.
The mechanisms of drug action and the relationship between drug concentration and effect: Concentration effect.
Determines the magnitude of effect at a particular concentration (Emax and EC50)
Application of mathematical concepts to real-life situations involving the absorption, distribution, metabolism/biotransformation and excretion/elimination of drugs in the body.
How are membranes involved in drug delivery?
Regardless of the method of drug administration - the ADME - of drugs involves transport of drugs across membranes.
Example of ADME involving membranes
Oral administration- drugs need to be absorbed at the stomach to enter systemic circulation - cross capillary cell membranes to leave the systemic circulation and reach their site of action - they need to cross the renal cell membranes to be eliminated.
Can drugs act in their bound form?
Why do some drugs need to cross membranes easily and some are better off if they do not?
If drugs are administered orally and needs to get to a site then it is beneficial to be absorbed easily.
Drugs used to treat the GI tract are better off if they do not cross the cell membranes easily - this way they can maintain high concentrations at their site of action and reduce entry into systemic circulation.
When will passage of drug be paracellular or transcellular?
It will depend on the type of tissue .
Explain paracellular passage of drugs
Explain transellular passage of drugs
Drug passes across the cell - all drugs will pass at least one or several cell membranes.
What are the mechanisms of transcellular passage of drugs?
Must pass through membranes by:
Active Transport - What are the types?
ABC? What type of transport?
ATP- Binding Cassette transporters
SLC? What type of active transport?
Secondary active transport.
Drugs engulfed by the cell.
What does the cell membrane consist of and why is it important to know for pharm?
Bilayer of amphipathic lipids -
Hydrophillic heads -out
Hydrocarbon chains - in
Lipid molecules are embedded in the bilayer and move laterally- provide membrane with fluidity and high electrical resistance - relative impermeability to polar molecules
Important to know in order to understand which drugs are more likely to cross these barriers.
What are factors that affect passive transport of drugs across membranes?
Molecular size and shape - small = better
Degree of ionization and polarity - less ionized/polar is better
Relative lipid solubility of its ionized/non-ionized forms.
Binding to proteins - reduces diffusion
Lipid water partition coefficient
The more lipid soluble the better
Barbital l/w = 1
Secobarbital l/w = 50
Why do most drugs have some affinity for water?
Most drugs have "some" affinity for water (hydrophillic - have some polarity) - so they can be dissolved and transported by the blood and other body fluids.
What factors influence the rate of diffusion across membranes?
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