Pharmacodynamics is the branch of pharmacology that studies how drugs affect the body. It focuses on the interactions between a drug and its target, such as receptors, enzymes, or other cellular components. Understanding pharmacodynamics helps researchers determine the drug's mechanism of action, effectiveness, and potential side effects. The relationship between drug concentration and its effects is a key aspect of pharmacodynamics. This includes concepts like dose-response relationships, which describe how varying doses of a drug can lead to different levels of response. By analyzing these relationships, scientists can optimize drug therapy for better patient outcomes.