Googling, supposedly paroxitine works better and can be used in combo with sildenafil. Don't know if available from India.
I use cheap sildenafil made in India, bought from legit Canadian pharmacy with doctor prescription. In Canada the US patent on sildenafil for ED is not recognized. I buy 88, 100mg tabs, for I think $169.
I crunch up the pills in my mouth and dissolve with squirts of propylene glycol on way to appointment, absorption in mouth mucous membranes is faster (<10 min) and higher bioavailability than swallowing them.
Propylene glycol is a food additive, (order from Amazon) which helps dissole sidenafil and transport it across mucous membranes. You can skip the propylene glycol, just crunch the tab, but it takes about twice as long to absorb. (Not similar sounding, but toxic ethelyne glycol, main ingredient in antifreeze!)
There are some sildenafil tabs made in India, designed to dissolve in mouth. This may be preferable if you can find them.