Introduction to pharmacology Flashcards
What is pharmacology?
The branch of medicine and biology concerned with the study of drug action
What does clinical pharmacology focus on?
Focuses on the application of pharmacological principles and methods in the medical clinic and towards patient care and outcomes
What is toxicology?
It is the study of the adverse effects, molecular targets, and characterisation of drugs or any chemical substance in excess
What are drugs?
They are substances that selectively interact with endogenous molecules to modify the functions of cells, physiological systems and living organisms
What can drugs used in?
Used in the treatment or prevention of disease
What are pharmaceuticals?
Drugs used in the treatment or prevention of disease
What are medicines?
Drugs used in the treatment or prevention of disease
What are the 2 types of drugs?
- Agonists
2. Antagonists
What do agonist drugs do?
They bind to and activate receptors to produce a biological response
What do Antagonists drugs do?
They block or dampens a biological response by binding to and blocking a receptor
What is the main difference between Antagonists and agonist drugs?
Agonist drugs activate receptors
Antagonist block receptors
What are drugs usually classified by?
By what they disease they are used to treat
Name 4 classifications drugs can fall in?
Drugs used :
- In chemotherapy
- To replace deficiencies of endogenous substances (insulin)
- To change the regulation of peripheral physiological systems (vasoconstrictors)
- to alter the function of the CNS or PNS
Name the 2 main branches of pharmacology
- Pharmacokinetics
2. Pharmacodynamics
What is Pharmacokinetics (PK) the study of?
How a drug is absorbed, distributed, metabolised or excreted (ADME).
What is Pharmacodynamics (PD) the study of?
How well the targets (e.g. receptors, ion channels, enzymes, and immune system components) respond to a drug.
How do drugs work?
By binding to receptors
Do drugs activate or inhibit receptors?
The do both
They can cause either the activation or inhibition of a regular body process to give a biological response.
Define Pharmacodynamics
The study of the physiological effects of drugs on the body and the mechanisms of drug action and the relationship between drug concentration and effect
What 4 factors about a drug are studied in Pharmacodynamics?
- Mechanisms of drug action
- Time course of drug effects
- Adverse drug affects
- Drug-drug interactions
What do Sedative-hypnotics do?
They depress the function of the CNS
What does the ED50 value of a drug measure?
The dose required to produce 50% of maximum response
What does potency mean in terms of drugs?
The amount of drug necessary to produce a certain effect
How are differences in drug potency evaluated?
By comparing the ED50 values
Does the most potent drug have a high or low ED50 value?
Low
What does efficacy mean in terms of drugs?
The maximum response that a given drug will produce irrespective of dose (Emax)
What does the Emax value measure?
the maximum response that a given drug will produce, irrespective of dose
How are differences in efficacy measured?
By comparing Emax values
Define pain threshold
The magnitude of pain stimulus required to elicit a response
Name 4 potential substances drugs can target in mammalian cells
- Receptors
- Ion channels
- Enzymes
- Transporters (carrier molecules)
What are receptors?
Receptors are the sensing elements in the system of chemical communications that coordinates the function of all the different cells in the body
Give some examples of receptors drugs can target
- Receptor operated ion channels
- G-protein coupled receptors
- Kinase-linked receptors
- Nuclear receptors
What effect can an agonist drug give when administrated to target a receptor?
- Ion channels can open/close
- Enzymes can be activated/ inhibited
- Ion channels can be modulated
- DNA transcription
What are ion channels?
Ion channels are essentially gateways in cell membranes
Selectively allow the passage of particular ions
What are the 2 important ion channel we need to know?
- ligand-gated channels
2. voltage-gated channels
Give an example of a ligand gated ion channel
Nicotinic acetylcholine receptor
What activates Nicotinic acetylcholine receptors?
the binding of two acetylcholine molecules
What does the Nicotinic acetylcholine receptor do?
As a ligand gated ion channel it permits the movement of positively charged ions from the synaptic cleft into the cytoplasm
What do agonist drugs do when they target ion channels?
Diffusion is blocked
What do antagonist drugs do when they target ion channels?
They increase or decrease the opening probability
How do drugs that target enzymes work?
The drug molecule is often a substrate analogue that acts as a competitive inhibitor of the enzyme
OR
the binding is irreversible and non-competitive
Give an example of a drug molecule that acts as a competitive inhibitor of enzymes
Captopril, acting on ACE
Give an example of a drug molecule that acts as a competitive inhibitor of enzymes
aspirin, acting on COX
If a drug blocks or dampens a biological response what type of drug is it?
Antagonist
If a drug binds to and activates receptors to produce a biological response what type of drug is it?
Agonist
How do ions and small organic molecules cross cell membranes?
- Channels (Ion channes
2. Transport proteins
Why do some ions and organic molecules need to used transport proteins?
Because the permeating molecules are often too polar
to penetrate lipid membranes on their own
Define Pharmacokinetics
The determination of the fate of substances administered externally to a living organism
What mechanisms do we check to describe how the nodes affected by a specific drug?
- ABSORPTION of the active substance by the organism
- DISTRIBUTION through the blood plasma and different body tissues
- METABOLISM the chemical changes of the substance in the body
- EXCRETION or elimination of the substance or the products of its metabolism
What us the acronym we use to remember how the 4 stages if deposition is divided?
ADME Absorption Distribution Metabolism Excretion
What is drug interaction?
Is a situation in where a substance affects the activity of a drug when both are administered together
Name the 6 ways drugs can be administered into the body?
- Oral or rectal
- Percutaneous
- Intravenous
- Intramuscular
- Intrathecal
- Inhalation
Name the 5 ways drugs can be eliminated from the body
- Urine
- Faeces
- Milk
- Sweat glands
- Expired air
What is absorption in terms of drug administration?
Absorption is the passage of a drug from its site of administration
into the plasma
What do you focus on in Pharmacokinetics?
usually focuses on concentrations of drug in blood plasma
What 2 assumptions are made in Pharmacokinetics when looking at drug concentration in blood plasma ?
- The plasma concentration bears a precise relation to the concentration of drug in the immediate environment of its target
- The drug response depends only on the concentration of the drug in the immediate environment of its target