Chem150 8:30am TR
Diphenhydramine is the active ingredient in Benadryl that works as an antihistamine for allergic reactions. A histamine is a chemical produced by the immune system to let a person know that an allergen is present. Some symptoms of an allergic reaction are hives, sneezing, itchy and watery eyes, itchy throat or nose, or difficulty breathing (Over-the-Counter Drugs, 2010). Diphenhydramine is a common over-the-counter drug that is taken to relieve these allergen symptoms.
Thankfully, our allergy symptoms can be relieved due to George Rieveschl’s invention of diphenhydramine (C17H21NO) in 1942. According to Carla Friedman (n.d.), “Rieveschl was originally working on a drug against muscle spasms, and ended up with an antihistamine” (Friedman, n.d.). Rieveschl’s research paved the way for more drugs to be produced to react with specific histamine receptors. Originally, The Parke-Davis & Company obtained the patent for Benadryl and Dr. Rieveschl earned a 5% royalty from the sales. Currently, this drug is manufactured by a subdivision of Johnson and Johnson known as McNeil-PPC (Friedman, n.d.). According to Statista (2018), in 2016, Benadryl produced $150.7 million in revenue for McNeil-PPC (“U.S. top OTC brands”, 2018).
Diphenhydramine can be identified by its physical and chemical properties. It is a solid that has a molecular weight of 255.361 g/mol. It is soluble in water at 37oC and is absorbed in the body within one hour. It is almost completed excreted through urine within 24 hours of taking it. Diphenhydramine has a biological half-life of 1-4 hours which means it takes approximately that long for the concentration of the drug to be reduced by one half in the body (PubChem, n.d.).
Besides treating allergies, diphenhydramine can help with many other conditions. For example, diphenhydramine has benefited some asthmatic patients and aids in relieving coughs from colds. Also, it subsides nausea associated with chemotherapy and motion sickness. This drug can alleviate pain from burns, cuts, bites, and even rashes from poisonous plants. Furthermore, diphenhydramine helps insomnia patients have a better quality of sleep and manages the early tremors of Parkinson’s Disease (PubChem, n.d.).
Diphenhydramine alleviates allergy symptoms by binding to the Histamine-1 (H1) receptor. This makes it impossible for the histamine to bind to the protein and eventually stop the reaction on bronchial, capillary, and gastrointestinal smooth muscles (PubChem, n.d.).
Taken in the correct dosage, diphenhydramine is completely safe to take. This drug has side effects such as drowsiness, diarrhea, nausea, vomiting, headaches, etc. However, it is possible to overdose on this medication, so it is important that it is taken responsibly. At high doses, the patient could develop anxiety, insomnia, hallucinations, and muscle tremors. (Over-the-Counter Drugs, 2010). Moreover, mixing diphenhydramine with alcohol or other Central Nervous System depressants acts as a sedative (PubChem, n.d.).
Researchers have discovered a link between dementia and long-term use of anticholinergic drugs like Benadryl. According to Beverly Merz (2017), “Anticholinergic drugs block the action of acetylcholine” (Merz, 2017). Acetylcholine is a type of neurotransmitter that is responsible for voluntary movement, learning, memory, sleep arousal, and attention. The production of too much acetylcholine causes depression and too little causes Alzheimer’s Disease, a form a dementia (AllPsych, 2018). The University of Washington and Group Health conducted a long-term study on 3,500 people to research adult changes in thought. Pharmacist Shelley Gray examined their records to explore all the drugs each participant took 10 years before the study. She discovered that people who used anticholinergic drugs were more likely to develop dementia as about 800 in the study eventually did. Since the production of acetylcholine reduces with age, the use of anticholinergic drugs like diphenhydramine are especially risky for the elderly. (Merz, 2017).
In my life, it is very important that I always have Benadryl on me. I am allergic to Amoxicillin, Penicillin, blue dye, seafood, and blackberries. I often have to take Benadryl after eating at a restaurant that serves fish because they cross-contaminate the grills and fryers with non-seafood items. When having an allergic reaction to seafood, my throat begins to itch and my lip swells. The diphenhydramine in Benadryl alleviates my symptoms within 20 minutes.
All in all, diphenhydramine is a very helpful drug when it comes to relieving allergy symptoms and a variety of other conditions. Its chemical make-up allows the drug to act as an antihistamine but can also act as a mild sedative. It is relatively a safe drug to use if taken responsibly and can be bought over the counter at any local pharmacy. However, to reduce the risk of dementia, this drug should not be taken long-term.
AllPsych (2018). Chapter 2: Section 2: Neurotransmitters. Retrieved from http://allpsych.com/psychology101/neurotransmitters/#.VgKkAd9VikoFriedman, C. (n.d.). George Rieveschl Discovers Benadryl. Retrieved from https://worldhistoryproject.org/1942/george-rieveschl-discovers-benadrylMerz, B. (2017, May 23). Common anticholinergic drugs like Benadryl linked to increased dementia risk. Retrieved from https://www.health.harvard.edu/blog/common-anticholinergic-drugs-like-benadryl-linked-increased-dementia-risk-201501287667National Center for Biotechnology Information. PubChem Compound Database; CID=3100. Retrieved from https://pubchem.ncbi.nlm.nih.gov/compound/3100Over-the-Counter Drugs. (2010). In UXL Encyclopedia of Drugs and Addictive Substances. Detroit, MI: Gale. Retrieved from http://go.galegroup.com/ps/i.do?p=SCIC&u=vja&id=GALE%7CCV2646400043&v=2.1&it=r&sid=SCICU.S. top OTC brands for allergy 2016 | Statistic. (2018). Retrieved from https://www.statista.com/statistics/296120/top-ten-us-over-the-counter-brands-for-cough-and-cold/