Premature ejaculation. Is it advisable.

Dr I am 46 yrs bachelor.i had never had sex before.iwas sexually very active and indulged in porn and masturbation. Last six months back I tried having sex with my female friend.She was willing and on numerous occasions we had engaged in sex.Initially few times I failed the moment I started entering her vagina and start stroking I ejaculate immediately. Even though she tried hard I could not satisfy her.i knew I had a problem. I consulted one urologist and he prescribed me medication Nano cap daily one with 5 mg effile for 2 months.During medication we had sex .I could feel the difference. My penis could get stiff and I had sex not once but twice that to for more than 15 min at one go.Then I started using manforce tab 50 mg and 100 mg 30 min before sex.it worked I was really enjoying .But my concern is is it advisable.