Trulance and Linzess perform similarly in clinical trials, and a large meta-analysis of over 10,000 patients found no statistically significant difference between them in efficacy, diarrhea rates, or the number of people who quit treatment because of side effects. Neither drug is clearly “better” overall, but they differ in ways that might matter to you personally: how they work in your gut, dosing flexibility, cost, and how quickly they relieve specific symptoms.
How They Compare on Effectiveness
Both Trulance (plecanatide) and Linzess (linaclotide) are FDA-approved for the same two conditions: chronic idiopathic constipation (CIC) and irritable bowel syndrome with constipation (IBS-C). A 2018 systematic review and meta-analysis pooling data from 15 clinical trials found both drugs significantly outperformed placebo for both conditions. When the researchers ran a meta-regression comparing the two drugs head to head, there were no statistically significant differences in how well they worked.
The joint American Gastroenterological Association and American College of Gastroenterology guideline on chronic constipation gives both drugs the same rating: a strong recommendation based on moderate certainty of evidence. They sit in the same treatment tier alongside prucalopride (Motegrity), meaning professional guidelines don’t favor one over the other.
How They Work Differently in Your Gut
Both drugs activate the same receptor on the lining of your intestines, triggering your cells to push chloride, bicarbonate, and water into the intestinal space. That extra fluid softens stool and gets things moving. But the way each drug reaches that receptor is slightly different.
Linzess is a 14-amino-acid peptide that activates the receptor regardless of the surrounding pH. It works the same way whether it’s in a more acidic or more alkaline stretch of your intestines. Trulance is a 16-amino-acid peptide designed to mimic uroguanylin, a natural hormone your body already makes. Because of that design, Trulance is pH-sensitive: it binds more actively in the mildly acidic environment of the upper small intestine, which is where uroguanylin naturally does its work.
In theory, this pH sensitivity could mean Trulance activates in a more targeted way, but clinical trial data hasn’t shown that this translates into a meaningful difference in outcomes or side effects for most people.
Diarrhea and Other Side Effects
Diarrhea is the most common side effect of both drugs, which makes sense given that they work by pulling water into your intestines. In the meta-analysis, both Linzess and Trulance caused diarrhea at significantly higher rates than placebo. For IBS-C specifically, Linzess at its approved dose (290 mcg) was about 8 times more likely than placebo to cause diarrhea, while Trulance at 3 mg was about 4 to 5.5 times more likely.
Those numbers might suggest Trulance causes less diarrhea, but the researchers noted something important: the clinical trials for each drug used different definitions of diarrhea, making a direct comparison unreliable. When they controlled for that difference statistically, they found no significant gap between the two drugs in diarrhea rates or in the number of patients who dropped out of trials because of it.
Both drugs carry an FDA boxed warning against use in children under 2 years old, based on animal studies showing fatal dehydration in neonatal mice. Linzess has since been approved for children ages 6 to 17 with functional constipation. Trulance does not currently have a pediatric approval.
Dosing Differences
Trulance comes in a single dose: one 3 mg tablet once daily, used for both CIC and IBS-C. There’s no dose adjustment between conditions.
Linzess offers more flexibility. It comes in 145 mcg capsules (the recommended dose for CIC) and 290 mcg capsules (the recommended dose for IBS-C). A 72 mcg dose also exists, which gives your doctor room to start lower if you’re sensitive to side effects or to step up if you need more relief. Both medications are taken once daily on an empty stomach, at least 30 minutes before your first meal.
How Quickly They Work
Linzess tends to show its effect on bowel movement frequency within the first week of treatment. Abdominal pain relief takes longer, typically beginning to separate from placebo in the first week but reaching its peak effect around weeks 6 to 9. That pain relief held steady through the end of 12-week trials. Trulance’s clinical trials show a similar early-onset pattern for bowel movements, though detailed week-by-week pain data is less well documented in publicly available reviews.
For either drug, give it at least a few weeks before deciding it isn’t working. The constipation relief comes faster than the belly pain relief.
Cost Can Be a Deciding Factor
Without insurance, the price gap is substantial. A 30-day supply of Linzess runs around $284 at retail, while Trulance costs roughly $617 for the same supply. That’s more than double the price for a drug with equivalent clinical performance.
Your actual out-of-pocket cost depends on your insurance formulary. Many plans place both drugs on specialty tiers, but Linzess has been on the market longer (approved in 2012 versus 2017 for Trulance) and tends to have broader formulary coverage. If cost is a concern, it’s worth checking whether your plan covers one but not the other, or whether manufacturer copay cards bring the price down.
Which One Might Work Better for You
Since the clinical data shows equivalent effectiveness and similar side effect profiles, the choice between Trulance and Linzess often comes down to practical factors:
- If you want dosing flexibility, Linzess has three dose options, letting you and your doctor fine-tune treatment. Trulance is one-size-fits-all.
- If cost matters, Linzess is significantly cheaper at retail and more likely to be covered by insurance.
- If you’ve tried one and it didn’t work, switching to the other is reasonable. The slight differences in how they activate receptors mean some people respond better to one than the other, even though population-level data shows them as equivalent.
- If you’re treating a child, Linzess is the only option with an FDA-approved pediatric indication (ages 6 to 17).
Neither drug is objectively superior. The best choice is the one that your body tolerates, your insurance covers, and your doctor can adjust to fit your symptoms.