Lubiprostone and Linzess are not the same medication. Lubiprostone (brand name Amitiza) and linaclotide (brand name Linzess) are two distinct prescription drugs that treat constipation through entirely different mechanisms. They’re often compared because they belong to the same broad category of drugs called secretagogues, which work by pulling more fluid into your intestines to soften stool and speed up transit. But the similarities largely end there: they target different receptors, carry different side effect profiles, and are approved for somewhat different conditions.
How They Work Differently
Lubiprostone is a fatty acid derived from a natural compound called prostaglandin E1. It activates a specific chloride channel (called ClC-2) on the surface of your intestinal lining. When this channel opens, chloride ions flow into the intestinal space, and water follows. The result is softer, more hydrated stool that moves through your system faster. Lubiprostone also appears to act on certain prostaglandin receptors, which may contribute to its effects on gut motility.
Linaclotide takes a completely different route. It binds to a receptor called guanylate cyclase C (GC-C) on the inner surface of your intestinal cells. This triggers a chain reaction that increases levels of a signaling molecule called cGMP, which ultimately opens a different chloride channel (CFTR) and drives fluid secretion. The elevated cGMP also has a secondary benefit: it can reduce the firing of pain-sensing nerves in the gut wall, which is why Linzess is specifically useful for people whose constipation comes with abdominal pain.
Approved Uses
Both drugs treat chronic idiopathic constipation (CIC) and irritable bowel syndrome with constipation (IBS-C) in adults. Beyond that, their approvals diverge.
Lubiprostone has one approval that Linzess does not: opioid-induced constipation (OIC) in adults with chronic, non-cancer pain. This was granted by the FDA in 2013. If you’re taking opioid pain medication and experiencing constipation as a side effect, lubiprostone is the secretagogue option with a specific indication for that problem. One caveat: its effectiveness hasn’t been established in people taking certain opioids in the methadone family.
Linzess, on the other hand, has a pediatric approval that lubiprostone lacks. The FDA approved Linzess for functional constipation in children ages 6 to 17, and for IBS-C in children 7 and older, at a dose of 145 mcg once daily. Children under 2 should not take Linzess due to the risk of serious dehydration.
Effectiveness for Constipation
Both medications significantly outperform placebo in clinical trials, though direct head-to-head comparisons are limited. In studies of chronic constipation, lubiprostone produced responder rates (patients achieving a meaningful increase in weekly bowel movements) of roughly 65% to 75% in the first week, compared to 29% to 49% for placebo. Linaclotide’s first-week responder rates ranged from about 78% to 84%, against placebo rates of 57% to 61%.
These numbers come from different trials with different patient populations and different definitions of “responder,” so a direct percentage comparison can be misleading. What the data consistently shows is that both drugs work well for most people, with noticeable improvement typically appearing within the first week of treatment. Over a 12-week period, around 39% to 41% of patients on linaclotide sustained an increase of at least two additional bowel movements per week for the majority of the trial, compared to 13% to 16% on placebo.
Side Effects to Expect
The most common side effects differ between the two drugs, and this is often a deciding factor when choosing one over the other.
- Lubiprostone’s signature side effect is nausea. It’s the most frequently reported complaint and tends to be more common in women. Taking it with food can help reduce nausea. Headache and diarrhea are also reported but less common.
- Linzess’s main side effect is diarrhea. For some patients this can be significant, particularly in the first few days. The diarrhea is a direct extension of the drug’s fluid-secretion mechanism. It’s typically managed by taking the medication on an empty stomach at least 30 minutes before the first meal of the day.
If you’ve tried one of these drugs and couldn’t tolerate it, the other may be worth discussing with your prescriber, since the side effect profiles are distinct enough that many people tolerate one better than the other.
Key Practical Differences
Both are taken orally, once or twice daily depending on the drug and indication. Linzess is taken once daily on an empty stomach. Lubiprostone is typically taken twice daily with food and water. Both are available only by prescription.
Cost can vary significantly depending on insurance coverage. Both brands have been on the market long enough that manufacturer savings programs exist, but neither has a widely available generic in the U.S. as of recent years. Checking with your pharmacy and insurance plan is the most reliable way to compare out-of-pocket costs.
For people dealing with opioid-induced constipation specifically, lubiprostone is the clear choice between the two since it’s the only one with FDA approval for that use. For patients who experience significant belly pain alongside their constipation, linaclotide’s ability to reduce visceral pain signaling gives it a potential edge. For children with constipation, Linzess is the only option of the two with pediatric approval.