Brief Answer:
Effexor (venlafaxine) clearly the cause

Detailed Answer:
Hello sir and welcome.

Thank you for writing to us.

I have gone through your query with diligence and would like you to know that I am here to help you as much as I can.

Effexor which contains the active ingredient venlafaxine has quite a few side effects, but some of the less common (although not rare) side effects include:
-Male sexual dysfunction
-Reduced libido
-Impotence
-Abnormal ejaculation
and a few others.
A recent study reported phase 3 side effects of lack of erection and lack of ejaculation in several subjects.

So in my opinion sir, the cause for your presentation is the effexor indeed.

I would also like to point out sir, as you are on flow XXXXXXX I am assuming you have been diagnosed with a prostate abnormality. Venlafaxine also contributes to prostate abnormalities like enlargement, inflammation and irritability. So please discuss this with your doctor as well.

If at all a solution is to be found, it is by replacing the venlafaxine with another effective drug. But please understand sir, that the depression is considered the more serious problem and not the sexual function. So your doctor will still aim at keeping the depression at bay, and at the same time find a drug which does not cause such undesired side effects (eg. sexual dysfunction).

I hope you find my response both helpful and informative sir. Please feel free to write back to me for any further clarifications, I would be more than happy to help you.

Best wishes.

---