Key takeaways
Lactulose (Constulose) and calcium polycarbophil (FiberCon) are both used to treat constipation, but they work differently and have distinct characteristics. Lactulose is an osmotic laxative that requires a prescription and works by drawing fluid into the gut to soften stool, typically taking 1 to 2 days to produce a bowel movement. In contrast, calcium polycarbophil is an over-the-counter bulk-forming laxative that keeps water in the stool to make it heavier and easier to pass, usually working within 12 to 72 hours. Lactulose can cause side effects like stomach pain and gas, while calcium polycarbophil is less likely to cause gas and bloating but can be a choking hazard if not taken with enough water. Additionally, lactulose is not suitable for people who are lactose intolerant or on a low-galactose diet, whereas calcium polycarbophil should not be used by children under 12 years old. Both medications have generic forms available, making them more affordable options for treating constipation.
