Drug receptors are typically proteins that interact with drugs, triggering a biological response. They are key players in determining the drug's efficacy and potency.
An agonist binds to a receptor and mimics the action of endogenous substances, leading to a pharmacological effect.
The therapeutic index (TI) is calculated as TD50 (toxic dose in 50% of the population) divided by ED50 (effective dose in 50% of the population). A higher TI indicates a safer drug.
Efficacy is the ability of a drug to produce a maximum therapeutic effect. It is different from potency, which is the amount of drug needed to achieve a specific effect.
An antagonist binds to a receptor without activating it and blocks agonists or other substances from binding, thereby preventing a biological response.
