Constipation is a common issue after bariatric surgery, due to changes in the digestive system and the decreased food intake. It's important to stay hydrated by drinking plenty of water and other fluids, as well as eating high-fiber foods like fruits, vegetables, and whole grains.
There are several over-the-counter medications that may be used to help with constipation, such as stool softeners (such as Colace, as you mentioned), laxatives (such as Miralax or generic versions), and fiber supplements (such as Metamucil or Benefiber).
It's always best to check with your surgeon or primary care physician before taking any new medication after bariatric surgery, since some medications may interact with the surgery or have other risks for bariatric patients.
It's also important to try to establish a regular bowel movement routine. This can include regular physical activity, eating at regular times, and avoiding dehydration.