How to fix urinary retention (frequent urination) caused by nightly benadryl use. how long after stopping to see results? any suggestions to help

Up to 24 hours: However if benadryl is causing this , better avoid and use an alternative , better through your doctor. This side effect of benadryl might not go away with repeated usage, also it can a be a side effect of other antihistamines, may be less with the newer ones as cetirizine or loratadine, so better run it by your doctor, good luck