Cilnidipine Shows Surprising Promise as a Potent Antiviral Agent Against Influenza A Virus

Medical News: In a remarkable discovery that could reshape the fight against seasonal and pandemic flu, researchers from the Southern Medical University in Guangzhou, China have found that cilnidipine - a common medication used for high blood pressure - can powerfully inhibit the influenza A virus (IAV). The findings bring hope for an effective repurposed treatment to combat flu outbreaks, especially with rising concerns over drug resistance and limited antiviral options.


Cilnidipine Shows Surprising Promise as a Potent Antiviral Agent Against Influenza A Virus

This Medical News report highlights how researchers from Zhujiang Hospital’s Department of Pulmonary and Critical Care Medicine, along with the NMPA Key Laboratory for Drug Metabolism and the Guangdong-Hongkong-Macao Joint Laboratory for New Drug Screening, revealed that cilnidipine exerts potent antiviral effects both in lab cultures and living organisms.
 
A New Way to Block the Virus at the Entry Point
Influenza A virus infects cells by first latching onto them, then using the cell’s own machinery to enter and multiply. The researchers discovered that cilnidipine acts during the very first stages of infection - specifically by stopping the virus from entering the cell. Cilnidipine blocks two key internalization pathways: clathrin-mediated and caveolin-mediated endocytosis. These pathways are like doorways the virus uses to sneak into cells.
 
Once the virus is inside a host cell, it fuses its membrane with the host’s and releases its genetic material to start replication. Cilnidipine also interferes with this process by binding to the HA2 subunit of the virus’s hemagglutinin protein, effectively blocking the fusion and halting the infection process.
 
Strong Evidence from Lab and Animal Studies
In lab experiments using various influenza A strains - including oseltamivir-resistant versions, cilnidipine significantly reduced virus replication, prevented cell damage, and lowered the production of viral RNA and proteins. The compound performed well against both H1N1 and H3N2 subtypes.
 
Cilnidipine also performed impressively in infected mice. Mice treated with cilnidipine showed a 90% survival rate, better than even the 80% survival rate seen in those treated with oseltamivir, a commonly used flu drug. The treated animals also had healthier lungs, lower levels of virus, and significantly reduced lung inflammation and damage.
 
Importantly, the study confirmed that cilnidipine’s effect was not due to its blood pressure-lowering properties. Even at higher doses, it did not cause drops in blood pressure in mice, suggesting its antiviral action is direct and specific.
 
Blocking the Virus’s Cellular Tricks
The team also uncovered how cilnidipine disrupts two critical signaling pathways that viruses hijack to enter cells: the PI3K-AKT and p38 MAPK pathways. These pathways help the virus to invade and set up shop inside t he body. Cilnidipine shuts down these virus-activated cellular responses, creating a hostile environment for infection.
 
Additionally, cilnidipine reduced the harmful calcium influx and reactive oxygen species (ROS) buildup inside cells that normally occurs during infection - both of which can worsen disease outcomes.
 
An Urgent Need for Repurposed Antivirals
Drug resistance is a growing problem with current influenza treatments. Oseltamivir, one of the most widely used antivirals, has seen waves of resistant strains emerge. Baloxavir, a newer flu drug, has also run into resistance issues. With vaccine efficacy varying each year due to viral mutations, having an alternative therapeutic strategy is critical.
 
Drug repurposing - using approved medications for new diseases - offers a faster path to treatments during outbreaks. Cilnidipine’s established safety profile and broad availability make it a strong candidate for emergency use during influenza pandemics.
 
What This Means Moving Forward
Cilnidipine is already used globally as a hypertension drug, which could accelerate its adoption for antiviral purposes pending clinical trials. Its ability to prevent both the entry and replication of influenza A virus, along with its minimal side effects, could make it a valuable tool in future flu seasons or pandemics.
 
The researchers suggest further investigations into how cilnidipine reshapes the internal environment of host cells during infection and believe this drug could also be explored for use against other respiratory viruses.
 
Conclusion
The study has shed light on cilnidipine as a powerful dual-action antiviral agent that can effectively block influenza A virus infection in both laboratory settings and animal models. By interfering with the virus’s ability to enter cells and disrupting its use of key cellular pathways, cilnidipine shows promise as a safe and easily accessible treatment for flu infections, including drug-resistant strains. This exciting discovery could pave the way for more rapid drug repurposing strategies to combat emerging viral threats.
 
The study findings were published in the peer-reviewed journal: BMC Medicine.
https://link.springer.com/article/10.1186/s12916-025-04022-0
 
For the latest on Influenza Viruses, keep on logging to Thailand Medical News.
 
Read Also:
https://www.thailandmedical.news/news/oseltamivir-tamiflu-found-to-be-hepatoxic-and-can-cause-liver-damage-in-flu-patients
 
https://www.thailandmedical.news/news/selenium-strengthens-immunity-and-helps-fight-viral-diseases-including-covid-19-and-influenza
 
https://www.thailandmedical.news/news/elderberry-extract-and-quinine-show-promising-antiviral-potential-against-influenza-and-covid-19
 
https://www.thailandmedical.news/pages/thailand_doctors_listings
 
https://www.thailandmedical.news/articles/influenza-or-flu