Lecture 1

What is pharmacodynamics?

The study of the biochemical and physiological effects that drugs have on the body, including how they alter bodily functions and responses.

What is pharmacokinetics?

The branch of pharmacology that focuses on the movement of drugs within the body, often summarized by the ADME principle.

What is terfenadine?

A nondrowsy antihistamine medication.

What receptor does terfenadine act on?

The H1 receptor as an antagonist.

What is terfenadine classified as?

A prodrug, meaning it is an inactive compound that is converted into an active form through metabolic processes.

How is terfenadine metabolized?

It is processed in the liver, where it is converted into its pharmacologically active form, fexofenadine, which effectively alleviates allergy symptoms.

What can terfenadine in its inactive form cause?

It may block potassium ion channels in the heart, potentially leading to disruptions in the heart's electrical activity and rhythm.

What liver enzyme metabolizes terfenadine?

The CYP3A4 enzyme.

What is a prodrug?

A pharmaceutical compound that requires metabolic conversion within the body to become active.

What are off target effects?

Unintended interactions that occur when drugs influence other receptor types or biological pathways beyond their intended target.

What is receptor theory?

A concept in pharmacology which states that receptors have a strong affinity for their naturally occurring molecules creating a chemical event (endogenous ligands), they are structurally selective for particular molecules, and they can become saturated as they interact with drug molecules.

How do most drugs bind to proteins?

Drugs predominantly attach to protein molecules through reversible binding, leading to a dynamic equilibrium between bound and unbound states.

What is the significance of drug binding to receptors?

Only those drugs that are bound to their respective receptors are able to exert physiological effects.

What types of interactions allow drugs to bind to receptors?

Drugs can bind through reversible interactions, typically electrostatic forces, or through irreversible covalent bonds.

What does receptor selectivity mean?

The ability of receptors to preferentially interact with certain molecules while still being able to bind other similar entities.

What determines the drug effect?

The overall effect of a drug is determined by the total number of available receptors, the proportion of those receptors that are bound by the drug, and the affinity of that drug for the receptors.