There actually are some patients with overactive bladder function who feel medicinal cannabis reduces their urinary frequency and urgency, and there is some laboratory data showing moderation of bladder activity is a possible minor effect of cannabis. However, urinary retention as an acute effect of cannabis seems highly doubtful except as a secondary effect. By that I mean consider how strongly bladder control can be affected by thoughts and emotions, especially at the extremes, and you can see why acute urination issues experienced when using cannabis are likely to have more to do with things other than the direct effects of cannabis on the bladder. Of course, if any other medications or substances are being taken then that might figure into it, and without knowing more medical info and history there isn’t much else to say. But if you have experienced more than a single occurrence of acute urinary retention it would be important to see a urologist and make sure nothing is going on that might require intervention.
I have this problem sometimes. I believe it’s over active mind. On pot, my mind is flying. I find concentrating on something does the trick. Sounds nutty, but I read the ingredients on my daughter’s shampoo bottles and think, what is this? Does the trick, and kind a freaks me out about using shampoo. What is that stuff?