I've used Immodium and Pepto in a crunch when things were bad and I had to show up for something but you're asking (I think) whether to use them regularly and that is something I wouldn't recommend. You really need to get the symptoms under control not mask the symptoms.
If your meds are not working to do that you need to change things.
Rowasa never helped D for me. It sometimes helps extreme C though.
Your not having a solid BM for so long means inflammation is present and a dysfunctional colon. You really need to get the inflammation down and OTC won't address that at all.
In remission April 2010 after 10 years of suffering and no remission ever
Jan 2010 started SCD diet (modified to remove dairy, fruit & juices)
Gluten-free=bleeding stopped in 3 days, 95% remission in 5.5 months on SCD
at 5.5 month stage homemade yogurt, hard cheese and some fruit OK
SCD Diet: Gluten/grain-free, starch-free, low carb, low-sugar
Supplements: tsp. fish oil, Vit D3 5000 with oil/fat, veggie juice, sunflower seeds, VSL#3, (4) Citrucel, (1) turmeric capsule, (1) calcium
Highly recommend: the book "Life without Bread" and the Specific Carbohydrate Diet
Rx: (6) balsalazide daily, mesalamine enema occasionally