Molecular Modeling and Preliminary Clinical Data Suggesting Antiviral Activity for Chlorpheniramine (Chlorphenamine) Against COVID-19

Chlorpheniramine, an Old Drug with New Potential Clinical Applications: A Comprehensive Review of the Literature

Chlorpheniramine Maleate (CPM), also known as chlorphenamine, is a potent alkylamine first-generation H1 antihistamine that has been used since the 1950s. CPM is a widely popular drug commonly used to treat allergic conditions, given its antihistamine properties. Although mainly used in over-the-counter treatment for cough and colds, various studies discuss a wide range of CPM's clinical uses, such as treating asthma, plasma cell gingivitis, chronic urticaria, and depression, among others. This antihistamine is usually taken orally; however, intravenous, intramuscular, and subcutaneous routes have been documented. Intranasal routes of this drug have recently been explored, especially due to its antiviral properties against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Accordingly, given CPM's extensive medical and safety profile, the present review explores this versatile drug's current and potential clinical applications. Although it is widely used mainly for treating common colds and aforementioned allergic conditions, CPM can be used for other clinical indications. The repurposing of CPM for other clinical indications, such as COVID-19, needs to be further explored through more extensive studies.

The Rise of SARS-CoV-2 (COVID-19) Omicron Subvariant Pathogenicity

During the COVID-19 pandemic, variants of the Betacoronavirus SARS-CoV-2, the etiologic agent of COVID-19 disease, progressively decreased in pathogenicity up to the Omicron strain. However, the case fatality rate has increased from Omicron through each major Omicron subvariant (BA.2/BA.4, BA.5, XBB.1.5) in the United States of America. World data also mirror this trend. We show that the rise of Omicron pathogenicity is exponential, and we have modeled the case fatality rate of the next major subvariant as 0.0413, 2.5 times that of the Alpha strain and 60% of the original Wuhan strain which caused the greatest morbidity and mortality during the pandemic. Small-molecule therapeutics have been developed, and some of these, such as chlorpheniramine maleate, may be useful in the event of an Omicron subvariant of higher risk.