Why Are There So Many Antihistamines? 🤧💊

About this Video

• Video Title: Why Are There So Many Antihistamines? 🤧💊
• Channel: Patrick Kelly
• Speakers: Patrick Kelly
• Duration: 00:22:36

Introduction

This video explores the history of antihistamines, detailing their discovery, development, and surprising applications beyond allergy treatment. The narrative unfolds in three parts: the discovery of histamine's role in allergies, the development of effective histamine-blocking drugs, and the unexpected expansion of antihistamines into various medications.

Key Takeaways

1. Histamine's Discovery: Sir Henry Dale's research on ergot in the early 20th century led to the isolation and identification of histamine, initially showing its effect on various systems, and later its role in allergic reactions. K. Watanabe later confirmed histamine's involvement in the allergic response.
2. First-Generation Antihistamines: Daniel Bovet and Anne-Marie Staub's work at the Pasteur Institute, along with Bernard Halpern's research at Rhône-Poulenc, led to the development of the first antihistamines, Antergan (phenbenzamine) and NeoAntergan (pyrilamine). These drugs, while effective, caused significant drowsiness. George Rieveschl's development of diphenhydramine (Benadryl) was another early success, but also caused drowsiness.
3. Second-Generation Antihistamines: The development of non-drowsy antihistamines like terfenadine (Seldane) and loratadine (Claritin) addressed the significant side effect of drowsiness from first-generation drugs. The regulatory hurdles and marketing strategies surrounding Claritin's approval and subsequent success are highlighted.
4. Beyond Allergies: The discovery of different histamine receptors (H1, H2, H3, H4) led to the development of medications treating conditions beyond allergies. The development of cimetidine (Tagamet), the first billion-dollar drug, for stomach ulcers is discussed as a prime example of utilizing H2 receptor antagonists. The unexpected role of antihistamines in motion sickness medication (dimenhydrinate, Dramamine) and antipsychotics is also mentioned.