How to maintain the hair that was grown due to Minoxidil after stopping it?

If the hair grow occurred from minoxidil, then continuing minoxidil is the only way to guarantee the growth Yes, it's possible finasteride could help. Any treatment you start must be continued forever - -you can not stop treatment. 

Thank you for your question. Studies have shown the combination of finasteride plus minoxidil gives a much better result than treatment with either of them alone. I would recommend resuming your minoxidil and continuing with the finasteride.I hope this was helpful - Dr. Moore.

Finasteride is a 5-alpha-reductase inhibitor and, as such, it blocks conversion of testosterone to the potent dihydrotestosterone (DHT).  DHT acts upon the follicle to cause thinning/loss.  Once you stop finasteride, you will lose that benefit and hair will resume thinning and/or loss.  While mostly anecdotal in their results, there are some products such as HairMedica, natural inhibitors (resihi mushroom, saw palmetto, green tea, alkalinization of the blood stream), and others which may help to inhibit the effect of 5-alpha-reductase.  Also mostly anecdotal in the results are treatments like Platelet Rich Plasma (PRP) injections.  

Any hair growth as a result of treatment would need continued treatment for maintenance.  Hair therapy is generally for maintenance rather than a short term curative goal. 
Good luck!