Introduction Diphenhydramine is a prototypical first-generation antihistamine with a long history of clinical use for allergic reactions, insomnia, motion sickness, and a variety of off-label applications. Its popularity in both prescription and over-the-counter preparations is a testament to its versatility, but its significant sedative and anticholinergic properties necessitate a deep understanding for safe and effective use. … Read more
Overview Histamine is a ubiquitous biogenic amine that influences vascular tone and permeability, sensory nerve activity (especially itch), airway smooth muscle, gastric acid secretion, and central nervous system arousal. Among its diverse receptor subtypes (H1โH4), the H1 receptor is the dominant mediator of the hallmark symptoms of immediate-type (type I) allergic reactions in the skin … Read more
Introduction Opioid analgesics comprise a diverse class of drugs used primarily for pain management. Derived from natural sources such as the opium poppy or synthesized in laboratories, these agents have been used for centuries for their potent analgesic and sedative properties. Opioids remain the most effective agents for controlling intense and certain chronic pain syndromes, … Read more