Amitiza vs Linzess: How They Differ and Which to Choose
Amitiza (lubiprostone) and Linzess (linaclotide) are both prescription medications that increase fluid in the intestine to treat chronic constipation, but they work through different pathways, treat different conditions, and cause different side effects. Amitiza’s most common side effect is nausea. Linzess’s is diarrhea. Both require a prescription, and no head-to-head trial has directly compared them.
This guide compares them side by side. For more on lubiprostone itself, see our guides to Amitiza and lubiprostone.
Quick comparison
| Amitiza (lubiprostone) | Linzess (linaclotide) | |
| Drug class | Chloride channel activator | Guanylate cyclase-C agonist |
| Chronic idiopathic constipation (CIC) | Yes, adults | Yes, adults |
| IBS with constipation (IBS-C) | Yes, women 18 and older | Yes, adults |
| Opioid-induced constipation (OIC) | Yes, adults with chronic non-cancer pain | Not approved |
| Labeled adult dose | CIC and OIC: 24 mcg twice daily | IBS-C: 290 mcg once daily. CIC: 145 mcg once daily (72 mcg may be used) |
| How to take it | With food and water | On an empty stomach, at least 30 minutes before a meal |
| Most common side effect | Nausea | Diarrhea |
| Boxed warning | None | Yes, serious dehydration risk in children under 2 (contraindicated under 2) |
Your provider sets your actual dose. These are the labeled doses (Amitiza label, Linzess label).
How they work
Amitiza activates ClC-2 chloride channels in the lining of the small intestine. Chloride moves into the gut, and sodium and water follow, which softens stool and helps it pass with less straining.
Linzess is a guanylate cyclase-C (GC-C) agonist. It acts on receptors in the intestinal lining to increase intestinal fluid and speed transit, which is why it also treats the abdominal discomfort that comes with IBS-C.
Neither is a stimulant laxative. Both work on the gut lining rather than forcing the muscle to contract.
What each one treats
The approved conditions are the clearest practical difference.
- Chronic idiopathic constipation (CIC): both are approved for adults.
- IBS-C: Linzess is approved for adults. Amitiza is approved for women 18 and older.
- Opioid-induced constipation (OIC): only Amitiza is approved, for adults with chronic non-cancer pain. Linzess is not approved for OIC.
Side effects
The side effect profiles differ, which is often what decides the choice.
- Amitiza: nausea is the most common. In CIC trials, nausea occurred in 29% of people on 24 mcg twice daily versus 3% on placebo, diarrhea in 12% versus under 1%, and headache in 11% versus 5%. Taking it with food and water reduces nausea. Shortness of breath was reported in 3% of CIC trial patients and has been reported after dosing.
- Linzess: diarrhea is the most common. In a CIC trial of the 72 mcg dose, diarrhea occurred in 19% versus 7% on placebo. Severe diarrhea was reported in 2% of people taking the 145 or 290 mcg doses.
These numbers come from different trials, populations, and doses, so they are not directly comparable. Both medications are contraindicated with a known or suspected mechanical bowel obstruction. Contact your provider if you develop severe diarrhea, vomiting, or severe abdominal pain.
Which works better, Linzess or Amitiza?
No head-to-head trial has directly compared them, so any claim that one clearly outperforms the other rests on indirect comparisons.
A 2024 systematic review and meta-analysis found lubiprostone, linaclotide, and elobixibat showed similar efficacy for chronic constipation, but different safety profiles: lubiprostone was linked to the highest risk of nausea and linaclotide to diarrhea (BMC Gastroenterology).
In IBS-C, a network meta-analysis found all secretagogues were superior to placebo. Linaclotide 290 mcg ranked highest overall for efficacy, though differences between drugs were generally small, and lubiprostone had lower diarrhea rates but more nausea (Gastroenterology, 2018).
In practice, the choice usually comes down to the condition being treated, which side effect you are more willing to manage, dosing preference, cost and insurance coverage, and how you responded to a medication before.
Pregnancy and other situations
Lubiprostone is generally avoided during pregnancy, and women who could become pregnant should use effective contraception while taking it. If you are pregnant or planning to be, talk to your provider before starting any prescription constipation medication.
If constipation started after you began a GLP-1 medication, neither drug is specifically labeled for that, but see our guide to Ozempic constipation for how lubiprostone fits.
Getting lubiprostone through Bummed
Bummed prescribes lubiprostone, the active ingredient in Amitiza, after an online intake reviewed by a licensed provider. Our product is the 24 mcg capsule, the labeled dose for chronic idiopathic constipation and opioid-induced constipation. If a provider prescribes it, the prescription is sent to a pharmacy near you for pickup, where you can use insurance or a discount coupon. The $49 fee covers your consultation, including 12 months of refills, and you pay the pharmacy for the medication.
If you have already tried Linzess or another constipation medication, tell the provider what happened. See lubiprostone through Bummed to get started.
Frequently asked questions
Is Linzess or Amitiza better?
Neither is better for everyone. No head-to-head trial exists, and indirect comparisons show similar efficacy for chronic constipation with different side effects. The right choice depends on your condition, tolerability, and coverage.
Is Linzess stronger than Amitiza?
“Stronger” is hard to define for these drugs. A 2024 meta-analysis found similar efficacy for chronic constipation. In IBS-C, one network meta-analysis ranked linaclotide highest overall, with small differences between drugs.
Which has more side effects, Amitiza or Linzess?
They have different ones. Amitiza is more associated with nausea, and Linzess with diarrhea.
Which is approved for opioid-induced constipation?
Amitiza is approved for OIC in adults with chronic non-cancer pain. Linzess is not approved for OIC.
Can you take Amitiza and Linzess together?
There is no standard reason to take both, and combining two medications that increase intestinal fluid could raise the risk of diarrhea and dehydration. Only do so under a provider’s direction.
Is there a generic Amitiza?
Yes. Generic lubiprostone has been available since 2021. See our guide to Amitiza for the cost comparison.
Do I need a prescription for either one?
Yes. Both require an online or in-person consultation with a provider who decides whether a prescription is appropriate.
This article is for general education and isn’t a substitute for medical advice about your individual situation. Prescription products require an online consultation with a physician who will determine if a prescription is appropriate.