While nerves to bladder may be involved in diseases affecting spinal cord and, thus, may have combined paralytic and bladder components, the combination is unlikely to happen with polio since the latter affects nerves beyond the spinal cord. People afflicted with polio, however, are as prone to develop lower urinary tract symptoms as any other person. The residual urine of more than 100 ml is worrisome, and needs to be confirmed on a repeat ultrasound study. Nasal stuffiness may occur with tamsulosin, and unlikely from dutasteride. Your Urologist would take your urinary symptom score, your clinical examination, investigation findings and flow parameters into account before advising whether you continue with both or only one of the medications in question.