Displaying 11 results of Diphenhydramine Stable Isotopes Diphenhydramine is a commonly used antihistamine medication that is often used to alleviate allergy symptoms and as a sleep aid. Stable isotopes of diphenhydramine are useful in pharmacokinetic studies, drug metabolism research, and in the development of new analytical methods for detecting the drug in biological samples. The use of stable isotopes allows for precise quantification and tracking of the drug in biological systems, providing valuable insights into its efficacy and safety.