There might be a rise in those taking this drug (6)
I believe the answer is:
viagra
'this drug' is the definition.
(I have seen 'Potency drug ' mean 'viagra' so perhaps 'drug' could also mean 'viagra')
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for viagra that I've seen before include "Sildenafil citrate" , "Drug treating impotence" , "potent drug?" , "Drug to improve potency" , "Drug aiding one's sex life" .)