Intro to drug kinetics and drug toxicity Flashcards
(45 cards)
What is pharmacology?
Study of the effects of drugs on living systems (in relation to therapeutics and toxicology).
Pharmacodynamics
Deals with the study of the biochemical and physiological effects of drugs and their mechanism of action. Effect of the drug on the body.
Pharmacokinetics
absorption, distribution, biotransformation and excretion of drugs. Effect of the body on the drug.
Toxicology:
adverse effects of drugs and chemicals.
Pharmacotherapeutics
use of drugs in the prevention and treatment of disease.
What do drugs do?
Modify physiological processes
Do NOT create new processes or effects
Drug effects are expressed in terms of alteration of a known function or process
Returns a function to normal operation
Changes a function away from the normal condition
Why are drugs used?
Prevent, diagnose and/or treat disease
Modify actions of other drugs
Analyse mechanisms or functions of an organism
What is a drug?
A chemical substance of known structure which, when given to a living organism, produces a biological effect.
What are the effects of drugs?
- Specificity: Drug produces only one effect.
- Selectivity: One effect predominates over a particular dose range – this is called the “therapeutic window” – within this range, the drug may be termed “selective”.
- Toxicity: Normally occurs beyond the therapeutic dose range. Some drugs may show toxicity at the higher end of the therapeutic doses (i.e.; adverse effects).
What is the goal of therapeutics?
Achieve “specificity”.
Name the mechanisms of drug activity
Deficiency, excess action and physiochemical environment
Drug activity mechanism - what is deficiency?
Replacement therapy for conditions such as iron, vitamin or hormone deficiency
Drug activity mechanism - what is excess action?
Chemical antagonists can reduce or block the effects of excess activity of normal process.
Antagonists can also block excess effects of exogenous substances (e.g.; reversal of overdose).
Drug activity mechanism - what is physiochemical environment?
Drugs can alter the environment or characteristics of a cell or tissue, changing its activity - “nonspecific effects”.
Define dose or concentration
Drug quantity in weight (mg) or volume (ml).
Define drug response or effect (types of effects)
The change occurring after drug administration. Effects include:
- Therapeutic effect: The desired or anticipated effect
- Side effect: Other than therapeutic effects occurring at therapeutic doses
- Toxic or adverse effect: Deleterious (harmful) effects usually occurring at higher doses
- Lethal effect: Death caused by very high drug dose
Define acceptor
Substances drugs bind to without causing any effect (e.g.; plasma proteins)
Define receptor
Cell component directly involved in reaction of some drugs and initiate the chain events leading to the drug’s observed effect.
What does a ligand do?
Bind to a receptor
What does an agonist do?
Initiates a response - many endogenous agonists (e.g NT/hormones)
What do antagonists do?
Does not initiate a response
Prevents agonist binding
What can receptors do?
Can: activate (agonist) or block (antagonist)
Converts the drug molecule signal (3D shape) to a biochemical signal (transduction) via effectors
Give examples of receptors
Membrane, enzymes, DNA, cytosolic proteins, ion channels
7-TMS receptors; 650 genes, activated by 70 ligands - target for half of all prescription drugs
Where are receptors located?
Cell membrane (transmitters/peptides)
Cytoplasm (steroids)
Nucleus (thyrosin/insulin sensitivity)
