basics of pharmacology

pharmacology def

interaction of chemicals with biological systems to yield therapeutic or other beneficial effects

selected characteristics of pharmacological agents

• intended for specific purposes

• usually either prevent or treat an illness

• administered in an appropriate physical form

• specific dosing regimens are required

pharmacology vs toxiciology

• pharmacology = interaction of chemicals with biological systems to yield therapeutic or other beneficial effects

• toxicology = interaction of chemicals with biological systems to yield adverse effects

pharmacodynamics (PD) vs pharmacokinetics (PK)

• pharmacodynamics (PD)

  • study of the biochemical and physiological effects of drugs and their MOA

  • effects of a drug on the body

• pharmacokinetics (PK)

  • study of the absorption, distribution, metabolism, and excretion of drugs (ADME)

  • effects of the body on the actions of a drug

most drugs work via __

receptors

• drug receptor or drug target = cellular macromolecule or macromolecular complex with which the drug interacts to elicit a cellular response

• drugs commonly alter the rate or magnitude of an intrinsic cellular response rather than create new responses

occupancy theory

response of a tissue to a drug (exogenous) or ligand (endogenous or exogenous) is a function of the # of receptors bound to the drug

• binding site = site on receptor where drug binds

• concentration of drug/ligand = important factor for extent of receptor binding

• typically need to reach a threshold of a receptor occupancy by drug/ligand to see the effect in the tissue (cumulative nature of response)

agonist

drug that binds to physiological receptors and mimic the regulatory effects of the endogenous signaling compounds

• primary agonist = drug that binds to the same recognition site on the receptor (orthosteric binding site) as the endogenous ligand

• allosteric agonist = drug that binds to different region on the receptor (allosteric or allotopic binding site) as the endogenous ligand

  • will still mimic the effects of primary agonists

antagonists

drugs that block or reduce the action of an agonist

• competitive = competes with an agonist for the same or overlapping site on the receptor

• noncompetitive = interacts with other sites on the receptor (allosteric antagonism)

• functional = indirectly inhibits the cellular or physiological effects of the agonist