1. Intro To Pharmacology Flashcards
Pharmacology
Study of substances that interact with living systems through chemical processes. What body does to the drug.
Dose-concentration relationship
Do not add “new” processes, but modify existing ones
Bind to regulatory molecules
Activating/inhibiting body processes
Replace endogenous substances
Pharmacodynamics
What drug does to the body
How and where it works (mechanism of action)
Concentration-effect relationship
Pharmacokinetics
What body does to the drug
Movement in and out of the body in various compartments
Relationship between pharmacodynamics and pharmacokinetics
Kinetics: Absorption, distribution and elimination
Dynamics: begins with drug concentration at site of action-leads to pharmacological effect, clinical response of toxicity or effectiveness
Drugs
Any substance that brings about a change in biological function through a chemical action
Augment or inhibit signaling molecules
Inhibit or stimulate receipts
Inhibit or increase enzyme activity
Aspects of drugs
Most are weak acids and weak bases
For systemic effects need to be able to be absorbed into the blood stream and distributed to receptors which have a chemical attraction (affinity) to drug
Goals of giving medications
Used to help treat: correct imbalances in homeostatic functions of the body
Replace naturally occurring compounds that are no longer made or become insensitive
Inhibit bacterial, viral, or fungal organisms that invade the body
Receptor
Drug target - most are proteins
Extra cellular: cell surface glycoproteins/transport proteins (most common)
Intracellular - nuclear receptors (transcription factors) for gene regulation
What is going on at receptor
Drugs have higher affinity at receptors then naturally occurring compounds
Increase affinity by increasing non-covalent bonds
Receptor affinity
Receptor affinity for drug binding determines the concentration of the drug needed to form a complex with the receptor
Some drugs can bind to a number of different receptors - want drugs to be as selective as possible
Selectivity is reduced as concentrations of drug at receptor site increase - toxicity, unwanted side effects
Selective drugs
Drug will only bind to to receptors at site of action - better drugs
Non-selective Drugs
Drug will bind to receptors all over the body, not just at site of action.
Causes unwanted side effects
Will occur with a selective drug if you keep increasing the dose
Selective drug at higher concentrations
Will bind to other tissues, because of the higher amount of drug present it will overwhelm receptors and cause a response
Reason we have dose ranges.
Receptors are Dynamic
Total number of receptors may limit the maximal effect of the drug in the system
Receptors are continuously made and can be influenced by the presence or a sense of prolonged exposure of agonists and antagonists
Actions of drugs on receptors may take time before seeing clinical differences /effects (SSRIs)
Ligand-Gated ion channels (inotropic receptors)
Ions into channel cause either hyperpolarization or depolarization
Time scale: milliseconds
Examples: Nicotinic, ACh receptor
