Drug repurposing is the process of using already approved drugs for a new disease.
One of the three greatest silver linings of the pandemic Covid-19 is to accord EUA ( Emergency Use Authorisation) to a lot of repurposed drugs in our fight against the Pandemic.
( The other two things are in the advancement of our knowledge in Viral diagnostics and Vaccination.)
Some examples of clinically established drugs that are already in use for other diseases and are now being used against Covid-19 are given below. This is a sort of ongoing Clinical trial of these drugs against SARS COV-2.
Of course, time will select the best fit and enter them into the pharmacology text books for the next generations.
Examples of Repurposed Drugs-
- Hydroxy-chloroquin– Rhematoid arthritis
- Ivermectin– Anti helminthic
- Fluvoxamine– SSRI anti psychotic
- Azithromycin– Chlamydial
- Lopinavir, Ritonavir– AIDS
- Favipiravir– RdRp inhibitor used for influenza in Japan
- Remdesivir– Ebola
- Tocilizumab– IL6 inhibitor, Rheumatoid arthritis
- And of course the time tested dexamethasone the universal anti inflammatory.
Advantage of repurposing-
Introducing a totally new molecule for human use is a very long arduous and costly affair. The drug safety has to be beyond doubt. This can be assessed only after controlled trials which needs ethical permission. These days it is impossible to run a control trial in a third world or even in a remote African country.
A proven drug doesn’t have this limitations hence can be safely tried against the new virus.
But there is one great limitation of repurposing a generic drug. Any new use of even an old drug needs control trials in human beings before getting authorisation.
Limitations of repurposing-
A Random Placebo Control Trial takes a lot of time and Money on the part of Drug manufacturers. An established drug has already crossed the normal time limits for Patents. Hence manufacturers cannot get the advantage of patents against this trials and recover their research costs. This a repurposed drug is no longer financially lucrative for MNCs. Hence there are not many backers for repurposing established drugs though this is the best way to tackle a pandemic on rampage. Then Greed is the motivator behind so many of our discoveries, philanthropy is not.
Only time will tell how many of these repurposed drugs will be accepted as the true effective Sars-Cov2 drugs and find a place in the future text books of pharmacology.
Dr Ramakanta's Ideas 