Used primarily as a research tool in pharmacology to study drug metabolism, particularly as a probe substrate for cytochrome P450 2D6 (CYP2D6) enzyme activity. It helps identify metabolic phenotypes such as poor metabolizers versus extensive metabolizers in human populations. Due to its potent antihypertensive effects, it has been used in studies related to blood pressure regulation and autonomic nervous system function. Its high sensitivity to genetic polymorphisms makes it valuable in personalized medicine research and in assessing drug-drug interactions involving CYP2D6 substrates.