Pharmacology basics Flashcards
Pharmacology is
the study of the interactions between a drug and organism (body, enzyme, etc)
Pharmacodynamics is
the study of how a drug affects the organism (biochemical, physiological, and molecular effects)
Pharmacokinetics is
the study of how the organism affects the drug
What is included within pharmacodynamics? (5 things)
Site of Action
Mechanism of Action
Receptor Binding
Postreceptor Effects
Chemical Interactions
What can pharmacodynamics be affected by? (3 things)
Disease or Disorder
Age
Drug–Drug interactions
In regard to pharmacodynamics, what are the three receptor subtypes?
Enzymes
Ion Channels
Membrane receptors
When drugs bind, what kind of chemical interactions can they go through? Which one do we like, and which do we typically avoid? (four things).
Electrostatic interactions are what we prefer (it occurs with intermolecular forces, always will have van Der Waals, hydrogen bonding prominent)
Hydrophobic interactions
Covalent bonds – typically avoid; intramolecular force; irreversible, can be problematic, shuts down receptor; certain bonds can cause DNA mutations
Stereospecific interactions (enantiomers) r, s, e, z
Some receptors are specific, some are not - this could lead to bad side effects with stereoisomers
The drug acts as a what to the receptor?
Ligand
What were the three drug properties discussed in class? What do we want in a drug?
Affinity – how well the drug binds to the receptor
Efficacy – how well the drug produces its desired effect
Potency – term used to compare the relative affinity of competing drugs
–
We want a drug to have high affinity, and high specificity.
What are the categories of drugs? (2)
Agonists – bind and activate receptors
Antagonists – bind, but do not activate receptors
Drugs can bind in two ways to a receptor. What two ways are those?
Competitive – bind reversibly
Non-competitive – either binds irreversibly or binds to create allosteric effects that diminish an agonist’s ability to bind to a different receptor.
What is pharmacokinetics, and how does concentration come in to play? What does us help us understand?
The study of the absorption, distribution, metabolism, and excretion of drugs from the body.
Concentration affects the ability of the drug to give its desired effect
Helps to better understand the following:
Drug administration
Therapeutic dosing
Time intervals between drug dosing
Toxic dosing
Adding what to a drug stops it from being oxidized without adding much weight or changing properties?
Fluorine
What methods of administration are available? Which is not very efficient? Which is the fastest? Which bypasses first pass effect?
Enteral (oral) – through the intestines; not very efficient, lose a lot of drug
Parenteral – other than the intestine (four below)
Intramuscular
Subcutaneous
Intravenously – fastest; bypass first pass effect
Inhalation
Absorption rate determines what?
Time to maximal concentration at the receptor to produce peak effect.
What is bioavailability?
how much of the administered drug is actually absorbed. (typically used for oral administration)
What are the 8 factors affecting bioavailability?
Molecular weight of the drug
Drug formulation
Drug stability (especially pH sensitivity)
First pass metabolism (typically in the liver)
Blood flow
Gastric emptying (food slows this process)
Intestinal motility
Drug interactions
What is distribution?
Effectiveness of the movement of the drug throughout the body
What are the 6 things distribution is influenced by?
Blood
Total body water
Extracellular fluids
Lymphatic fluids
Cerebrospinal fluids
Protein-binding
What do drug solubility properties help us determine?
help determine ability of drug to be distributed to the desired receptor site.
What must be done to a drug to make it more soluble? Can it be too soluble?
The drug has to be more ionized; can’t be too soluble, otherwise it will have a hard time crossing membranes.
What is metabolism, and what does it do? What does it have the potential to do?
Breakdown of drugs into metabolites
Prodrugs – convert from inactive form to active form
Typically inactivates the drug ahead of excretion
Has the potential to lead to the formation of toxic metabolites
What are two common processes of metabolism? Which is MORE common?
Hydrolysis (esters, amides, and nitriles) – typically in pancreas, etc
REDOX reactions (Cytochrome P450 enzymes in the liver) – most common
What is excretion?
Removal of the drug and its metabolites from the body
