Pharmacodynamics

Study of the biochemical and physiologic effects of drugs and the molecular mechanisms by which those effects are produced.

Response gets more intense with increasing dosage.

Biggest effects a drug can produce.

Drug that produces its effects at low doses.

Functional macromolecule in a cell to which a drug binds to produce its effects.

Mimic or block the action of the body's own regulatory molecules and alter the rate.

• 1. Cell membrane-embedded enzymes
• 2. Ligand-gated ion channels
• 3. G protein-coupled receptor systems
• 4. Transcription factors

Drug interacts with one type of receptor and receptor regulates a few processes.

Drug interacts with multiple receptor and receptor regulates multiple processes.

• 1. Strength of the attraction between a drug and its receptor.
• 2. Inc affinity Inc potency

• 1. Ability of a drug to activate receptors.
• 2. Inc intrinsic activity Inc maximal efficacy

• 1. Molecules that activate receptors.
• 2. Modified Occupancy Theory: yes affinity, yes intrinsic activity

• 1. Drugs that prevent receptor activation by endogenous regulatory molecules and by other drugs.
• 2. Modified Occupancy Theory: yes affinity, no intrinsic activity

Binds irreversibly to receptors.

Binds reversibly to receptors.

Can act as agonists and antagonists and have moderate intrinsic activity.

Over exposure of cells to agonists.

Over exposure of cells to antagonists.

Dose required to produce a defined therapeutic response in 50% of the population.

• 1. LD₅₀:ED₅₀ ratio
• 2. High TI = safe
• 3. Low TI = unsafe