Fundamental Principles of Pharmacology I Flashcards
Definition of drugs
Exogenous molecules that mimic or block the action of endogenous molecules or systems
Even though they are derived from exogenous sources, they may be chemically identical, related or distinct from endogenous molecules
Definition of phamacodynamics
What a drug does to an organism
The sum of all the actions of a drug
Definition of phamacokinetics
What the organism does to the drug (ADME)
Determines how quickly a drug acts
Definition of intraarterial (IA)
Liquid injected into an artery, v rare in human medicine
Definition intracerebroventricular (ICV)
Injected into the cerebral ventricles
Definition of intradermal
Injected into the skin layer (liquid/suspension)
Definition of intrathecal (IT)
Injected into the membranes that enclose the spinal cord
Definition of transcutaneous
Fine powder blaster through the skin under pressure using a device or by diffusion from an adherent pathc
Definition of proprietary name
Brand name
Definition of common name
Active ingredient in a drug
Definition of chemical name
Tells you the chemical composition
Definition of assay
Investigative procedure for qualitatively assessing or quantitatively measuring the presence, amount or functional activity of the analyte
Definition of chemical library
Compound library, collection of stored chemicals with associated info such as the chemical structure, purity, quantity and physiochemical characteristics
Definition of combinatorial chemistry
Synthetic methods that make it possible to prepare a large no of compounds in a single process
What are drugs
Exogenous molecules that mimic/block the action of endogenous molecules or systems
Can be
- chemically identical to an endogenous molecule
- related to an endogenous molecule
- chemically distinct from any endogenous molecule
How do drugs function
The lock and key model
Drug molecule with complementary shape to the receptor binds
This binding produces an effect
What are the 3 types of pharmacological receptor
Physiological receptor
Other proteins
Nucleic acids
Describe how physiological receptors work
What are examples of these receptors
Endogenous proteins that are the receptors for endogenous chemical signalling compounds (hormones, NT)
Adrenergic, cholinergic, SNS, PNS
Describe how other proteins function as receptors
What are examples of these receptors
Enzymes, ion channels
Drugs bind to specific sites on proteins, prevent them from functioning or stimulate them
Describe how nucleic acids can function as receptors
Drugs bind to regulatory sites on nucleic acids to influence gene expression or protein synthesis
Describe how agonists and antagonists function
Agonists bind to the complementary receptor => response
Antagonists bind to the complementary receptor => prevents receptor from being activated
Describe how reversible and irreversible drugs function
Why is the type of binding important
Reversible drugs
-Ionic and can have hydrophobic interactions between the receptor and the drug
Irreversible drugs
-Covalent bonds cannot be broken easily
Determines drugs primary effects
What is the difference between pharmacokinetics and pharmacodynamics
Pharmacodynamics, what a drug does to an organism
The sum of all the actions of a drug
Pharmacokinetics, what the organism does to the drug (ADME)
Determines how fast a drug acts
What is absorption
What is it influenced by
How much drug entrees the system and the speed of entry
- Chemical properties of drug
- Molecular size
- Lipid solubility/ionization
- Chemical, metabolic vulnerability
- Routes of administration
- Properties of the patient
How does the route of administration affect the absorption of a drug
Each route has a different barrier to absorption
- IV, no barriers
- PO, absorbed by the gut => into the bloodstream => metabolized by the liver
How do the properties of the patient affect the absorption of a drug
- Fat, thin (affects lipophilic drugs)
- Light, heavy (heavy people may need a larger dose)
- Fed, empty stomach (affects absorption in GI)
- Healthy, ill (hepatic disease => impaired metabolism, renal disease => impaired excretion)
What is distribution
What is it influenced by
What happens after absorption
In order to achieve its effects, drug may need to diffuse through tissue/carried in blood
- Blood soluble
- Stick to proteins or cells
- Does it concentrate in fats or aqueous solutions
- Does the patient have adequate circulation
What is metabolism and excretion
What is it influenced by
Duration of action determined by metabolism and excretion
If excreted rapidly, may have short duration of action
- Location of metabolism and excretion
- Health of liver and kidney
- Whether metabolites are toxic
What are the 5 ways of categorizing drugs
Proprietary name, brand name Common name, active ingredient Chemical name, chemical composition Therapeutic use, its function Mechanism, how it works
Describe the preclinical pathway in making a new drug
Basic research info (science behind a biological process)
Idea (Based off scientific theory)
Hypothesis (Forms basis of idea for drug)
Assay systems (Combining natural products, compound libraries, combinatorial chemistry => starting chemicals => assay system)
Once an active chemical is found
Optimized
Tested on animal models
Becomes a drug candidate
Describe Phase 0 in a clinical trial
Subtherapeutic doses in humans to work out pharmacokinetics
Can include tests on humanized animals
Not expected to have an effect
Describe Phase 1 in a clinical trial
Small scale involving 20-80 healthy volunteers
Understand properties, side effects and safety
Tolerability and dose findings found here
Describe Phase 2 in a clinical trial
Medium scale involving 100-300 patient volunteers
Understand side effects and safety and effectiveness
Describe Phase 3 in a clinical trail
Large scale involving 1000-3000 patient volunteers
More uncontrolled variables
Understand side effects and confirms effectiveness
Comparisons with currently available medicines
Who can you register a new drug with
UK, Medicines and Healthcare Regulatory Agency (MHRA)
EU, European Medicines Agency (EMA)
US, Food and Drug Admin (FDA)
Describe Phase 4 in a clinical trial
Post registration studies, every prescription is still a test
Test on different populations for long term safety
