Key takeaways
Lactulose (Constulose) and lubiprostone (Amitiza) are both prescription medications used to treat constipation, but they work in different ways and have different uses. Lactulose is an osmotic laxative that draws fluid into the gut to soften stool, making it easier to pass. It is typically used for chronic constipation and can take up to two days to work. On the other hand, lubiprostone is a chloride channel activator that increases fluid in the intestines, helping stool pass more easily. It is used for long-term constipation due to unclear causes, opioid-induced constipation, and irritable bowel syndrome (IBS) in women. Lubiprostone works faster, with many people having a bowel movement within 24 hours. Lactulose is available as a lower-cost generic, while lubiprostone is also available as a generic but may still be expensive. Common side effects of lactulose include stomach pain and gas, whereas lubiprostone can cause nausea and diarrhea. Additionally, lubiprostone is not approved for children or for opioid-induced constipation related to cancer pain, while lactulose is not suitable for those who are lactose intolerant or on a low-galactose diet.
