After the divorce I move to the west coast and got a new doctor. He looked at my med's and suggested I get off of Pristiq, which my previous DOC put me on 3 years ago. He said that studies were showing Pristiq was a erection killer in some cases. Pristiq is a anti depression medication. It took 2 months to get off the drug and there were some really bad withdrawal symptoms. Afterwards my mind felt so clear, like a fog was lifted. I started to have a dramatic increase in penis sensitivity and desire. I began to have erections again, nothing to write home about (about 60%) but they were there. My new Uro want to me to try Tri-Mix again and prescribed alp 10 pap 12 phent 1. I was suppose to go to see him next week to try the process again. After failed injections at such a high dose in the past I had little hope. Well my new girl friend (who has know idea about my problem) decided it was time for us to get BUSY! last night. We had fooled around orally but not intercourse. In desperation I put 15 units of the new mix in the syringe and injected. In 3-4 minutes I had a Rock hard erection " I was Fricken amazed" and thankfully so was she..
..Im not saying you should use your med's before seeing the DOC. 
.but i had used it before. 3 years ago my ED got worse..same time I started Prisiq.2 months after I stopped using Pristiq and 15 units of a lower concentration Tri-Mix and I was a rock-star again. Wow the emotional toll ED is so terrible. Please be careful using pristiq.
I hope this helps you.