Used as an early antihistamine in the treatment of allergic conditions, though its use has been largely discontinued due to the development of more effective and selective agents. It also showed alpha-adrenergic blocking activity, which led to its use in research settings to study vascular responses and neurotransmitter regulation. Due to its ability to block certain receptors, it was investigated for potential use in managing hypertension and related cardiovascular conditions, but it is not used clinically for this purpose today. Currently, it serves mainly as a reference compound in pharmacological studies involving receptor antagonism.