Influenza-existing drugs and treatment prospects.

Influenza is a century-old disease that continues to baffle humans by its frequently changing nature, seasonal epidemics, and occasional pandemics. Approximately 9% of the world's population is infected by the influenza virus annually. The emergence of novel strains because of rapid mutations as well as interspecies disease contamination, limits the efficiency of strain-specific vaccines. Anti-influenza drugs such as neuraminidase inhibitors, M2 ion channel inhibitors, etc. have become the first line of defense in prophylaxis and early containment of the disease. But the growing drug resistance due to drug-induced selective pressure has also limited the efficacy of those drugs. Because we can't predict the next strain types, their virulence, or the severity of the next epidemic/pandemic caused by influenza virus, we ought to gear up for the development of novel anti-influenza drugs with a broad spectrum of reactivity against all strains and subtypes, better bioavailability, easier administrative pathways, and lesser adverse effects. Various new compounds with each having significantly different target molecules and pharmacologic activity have shown potential against influenza virus strains in laboratory situations as well as clinical trials. We should also consider combination therapy to boost the efficacy of existing drugs. This review is aiming to succinctly document the recent signs of progress regarding anti-influenza drugs both in the market and under investigation.