Common Antihistamines Show Potential in COVID-19 Treatment: A Breakthrough in Cell Testing

22 March 2024

In a significant development in the ongoing battle against the novel coronavirus, a recent study has suggested that certain commonly used antihistamine medications might have the potential to prevent the virus responsible for COVID-19 from infecting cells. The study examined the effects of three particular antihistamines: hydroxyzine, diphenhydramine, and azelastine, in laboratory conditions and found promising results that could open new avenues in COVID-19 treatment modalities.

Leah Reznikov, Ph.D., an Assistant Professor of Physiological Sciences at the University of Florida (UF) College of Veterinary Medicine, alongside David A. Ostrov, Ph.D., Associate Professor of Immunology and Pathology at the UF College of Medicine's Department of Pathology, Immunology, and Laboratory Medicine, spearheaded this groundbreaking research. Their collaborative efforts were primarily focused on identifying currently authorized medications that could potentially interfere with the infectious mechanism of the SARS-CoV-2 virus, the pathogen behind COVID-19.

The researchers embarked on this journey by leveraging healthcare databases to investigate if individuals taking specific antihistamines exhibited lower infection rates. Their analysis included medical records of around 240,000 Californians, which revealed that people aged 61 and over who were on specific antihistamines seemed to have reduced chances of contracting COVID-19 compared to those who weren't. These findings laid the groundwork for subsequent experiments that combined human and primate cells to assess the antiviral efficiency of these drugs against the virus.

In the laboratory, the team tested the antivirus capacity of the medications and found that hydroxyzine, diphenhydramine, and azelastine effectively inhibited the virus's ability to infect cells. Notably, hydroxyzine and azelastine require prescriptions for use, whereas diphenhydramine can be easily procured over-the-counter and is widely known by its brand name, Benadryl, often used to treat cold and allergy symptoms. The potency of these drugs against SARS-CoV-2 in the cell tests is a promising step forward; however, it is imperative to conduct clinical trials to confirm their effectiveness and safety in preventing, treating, or serving as an adjunct therapy in severe COVID-19 scenarios.

The precise mechanisms through which these antihistamines exert their inhibitory effect on the SARS-CoV-2 virus are not yet fully understood. This emphasizes the need for further research to decipher exactly how these drugs interact with the virus and potentially disrupt its replication process. A key area of interest in this ongoing investigation is the role of sigma receptors. These proteins play crucial parts in cellular communication networks and might be involved in the process by which the virus replicates inside human cells. Understanding this interaction could unlock new therapeutic strategies against COVID-19.

While the study's results are indeed promising, they also come with a note of caution. The observed correlation between antihistamine usage and reduced infection rates does not establish a direct cause-and-effect relationship. As such, the research community urges the public to refrain from self-medicating with these drugs as a preventative or treatment measure for COVID-19 without proper clinical evidence supporting their efficacy in such contexts. Self-medication could potentially lead to adverse effects or interfere with existing medical conditions, underscoring the importance of conducting comprehensive clinical trials.

As the world continues to face the challenges posed by the COVID-19 pandemic, discoveries like these offer a glimmer of hope. The possibility that medications already available and widely used for other conditions could be repurposed to fight this devastating virus is an exciting prospect. It highlights the importance of innovative scientific inquiry and the potential to find solutions in unexpected places. The journey from laboratory findings to clinical application is complex and requires rigorous testing and validation, but the path is now set for further exploration. Researchers are eager to continue their work, delving deeper into how these antihistamines could contribute to the global effort to manage and eventually overcome COVID-19.