I'm experiencing penile discharge for the second time in less than 2 months, but STI tests came back negative. I'm 25 years old, so it can't be prostatitis. The first time, the ST I tests were negative and I was prescribed doxycycline, and it cleared up. Now it's back, I assume because my girlfriend didn't get treated since STI's were ruled out. I was given a rocephin injection and four tablets of azythromycin this time but my symptoms haven't shown any signs of slowing down.