Pharmacology Flashcards
What is a medicinal product?
- Any substance or combination of substances presented for treating or preventing disease in human beings or animals
What is medicines management ?
- The clinical, cost effective and safe use of medicines to ensure patients get the maximum benefit from the medicines they need, while at the same time minimising potential harm.
What is pharmocology?
Pharma = drug Ology = Study off
- It is the science that looks at the composition effects of an uses of different drugs.
- A drug is any chemical that affects any living organism
What is pharmacodynamics?
- This describes the action of a drug
- The mechanism of effects the drug has on the body - at a molecular, cellular and tissue systems level
- for example a drug may be given for therapeutic action which aims to reverse or modify changed to regain homeostasis
What is the receptor theory (lock and key)?
Transmitter = the key Receptor = the lock
- When the key opens the lock we get an action
- Signal molecule
- binds too
- Receptor protein
- activates
- Intracellular signal molecules
- alters
- Target proteins
- create
- Response
How does adrenaline increase your heart rate?
- Adrenalin (the key) is released by the adrenal medulla
- Travels to the heart and acts on the alpha and Beta receptors (lock)
- This increases the heart rate and force of contraction ( outcome)
- Adrenalin in this pathway is referred to as a signal molecule
What are receptors?
- These are glycoproteins in cell membranes that recognise and bind to ligands
- Ligands are smaller molecules (e.g drugs) that are are capable of ‘ligating’ themselves to the receptor protein
Binding = shape change of receptor = generation of biochemical reaction inside the cell known as (‘ Signal transduction’) leading to several reactions called ‘secondary messengers’ that is eventually translated into a biological response e.g muscle contraction, or hormone secretion
- The more receptors involved the bigger the response
What is pharmacokinetics?
- This is the movement of drugs inside the body
This includes: - Absorption = A - medication at site of administration
- Distribution = D - medicine in plasma (medicines in tissue)
- Metabolism = M- medicine in plasma (metabolites in tissue)
- Excretion = E - medicine and metabolites in urine bile or faeces
(ADME)
A knowledge of both pharmacodynamics and pharmacokinetics is essential to understand what drugs do and how they do it
What is drug absorption?
Drugs must cross biologic barriers e.g epithelial/ endothelial
- This can be done in two ways:
1- active transport
2- Passive diffusion
What is active transport?
- Movement across a cellular barrier
- It requires ATP to move the drug from a lower concentration to a higher concentration
What is passive diffusion?
- Cross cellular barriers
- Moves from an area of high to low concentration by simple diffusion
- However this is dependent on the chemical size, Ph, solubility of drug, surface area for absorption (e.g villi/ microvilli ) vascularity, presence or absence of food in stomach and presence of enzymes, acidity
- Most drugs are distributed via diffusion
What factors affect drug distribution?
- Small molecules diffuse more rapidly the large
- Ph effects the nature and absorption of the drug e.g acid drugs are better absorbed in an acid medium and base drugs are better absorbed in abase medium.
- Cell membranes are mainly lipid ( fatty_ materials. Only lipid like substances (lipophilic ) substances can cross easily and rapidly
- Most drugs act on receptors (usually protein)
- Factors such as the chemical nature of the drug and route of administration wil determine distribution of the drug.
What is drug ,metabolism?
- Drug metabolising enzymes have evolved as a defence against non-medical chemicals taken up from the environment and can be found in organs e.g skin, lungs, kidneys
- Drugs are chemically broken down into the liver by cytochrome P45O enzymes and made water soluble to be extracted via urine
- Chemical modifications higher or lower a drugs pharmacological activity and/or half life
What is an agonist?
- These bind to receptor proteins= produce a conformational change to enhance a biological response.
- When a drug stimulates the receptors it is an agonist
- An example would be Adrenaline
What is an antagonist?
- These bind to receptor proteins but do not produce the conformational change that initiates an intracellular signal
- Occupation of the receptor by a competitive antagonists, prevents binding of other ligands and so antagonises the biological response.
- An example of this is MORPHINE
