If your doctor mentioned Amitiza for chronic constipation, you probably have questions before you fill the prescription. Here’s what it treats, how it works, what to expect, and how the brand-name version compares to generic lubiprostone.
New to the basics of how digestion and bowel habits actually work? Our constipation guide is a good place to start before diving into a specific medication.
What Is Amitiza?
Amitiza is the brand name for lubiprostone, a prescription medication first approved by the FDA in 2006. It belongs to a drug class called chloride channel activators. This medication is FDA-approved to treat:
- Chronic idiopathic constipation (CIC) in adults
- Irritable bowel syndrome with constipation (IBS-C) in women 18 and older
- Opioid-induced constipation (OIC) in adults with chronic non-cancer pain
“Idiopathic” simply means there’s no single identifiable cause. If standard fiber and over-the-counter laxatives haven’t moved the needle, this drug works through a different mechanism than most of them. For a broader look at where it fits among prescription options, see our chronic constipation treatment options guide.
Generic Amitiza: Cost and What’s Different
The generic name for Amitiza is lubiprostone. Generic lubiprostone has been available since 2021, and it’s usually far cheaper than the brand. Here’s what that means for you:
- Same active ingredient, same effectiveness. The generic contains the identical active compound as the brand-name version and must meet the same FDA quality and efficacy standards.
- Significantly lower cost. The brand-name product can run several hundred dollars a month at retail price, while the generic is typically available for a fraction of that with a discount coupon or through insurance. Actual prices vary by pharmacy and coverage, so check with your provider or pharmacy for current numbers. As of October 2026, the price ranges from $42 – $55 for generic Amitiza, according to GoodRx.
- Ask before you assume. Some insurance plans cover one version but not the other, and some prescriptions are written brand-only. If cost is a concern, ask your prescriber whether the generic fits your situation.
Why can lubiprostone still be expensive? Even as a generic, prices vary widely by pharmacy, and some insurance plans require prior authorization or ask you to try other laxatives first before they’ll cover it. A discount coupon or a different pharmacy can make a big difference.
Curious how it stacks up against a different laxative entirely? Our lactulose page covers another commonly prescribed option, and lactulose side effects is useful if you’re comparing tolerability.
How It Works
The medication activates chloride channels (specifically ClC-2) in the lining of your small intestine. This increases fluid secretion into the intestine, which softens stool and helps it move more easily, without stimulating the muscle contractions that harsher stimulant laxatives rely on. If you want the fuller picture of what “motility” means and why it matters, we cover that in how to improve gut motility.
Dosage and How to Take It
Dosing depends on what it’s treating:
- Chronic idiopathic constipation: 24 mcg twice daily
- IBS-C: 8 mcg twice daily
- Opioid-induced constipation: 24 mcg twice daily
Capsules should be swallowed whole with food and a full glass of water. Don’t break, crush, or open them. Taking it with food also helps reduce nausea. For a closer look at the 24 mcg strength specifically, see our lubiprostone 24 mcg capsule page.
Always follow your prescriber’s specific instructions. This is general information, not a substitute for your own dosing plan.
Possible Side Effects
The most common side effect is nausea, reported in roughly 3 in 10 people in clinical trials (less common in patients over 65). Other side effects include:
- Diarrhea
- Headache
- Abdominal pain or bloating
- Stomach discomfort
Taking it with food lowers the chance of nausea. Contact your doctor if you develop severe diarrhea, or if you notice symptoms like fainting, rapid heartbeat, or swelling, which have been reported rarely after starting treatment.
This medication isn’t right for everyone. It’s contraindicated if you have a known or suspected mechanical bowel obstruction, and it should be avoided if you already have severe diarrhea. It’s classified as Pregnancy Category C, so talk to your doctor before starting it if you’re pregnant, trying to become pregnant, or breastfeeding.
Consult with a medical provider before starting any medications, especially if you’re pregnant, breastfeeding, or managing another health condition.
Who Should Consider This Medication
It can be a good option if over-the-counter laxatives and fiber haven’t been enough, especially for chronic idiopathic constipation, IBS-C, or constipation caused by opioid pain medication. It’s not the right starting point for everyone, and it requires a prescription for a reason: a provider needs to rule out things like bowel obstruction first and make sure it fits your full health picture.
Bummed offers generic lubiprostone prescription online through a straightforward consult, with a licensed provider reviewing your history before anything is prescribed.
Amitiza FAQs
How quickly does Amitiza work?
Many people have a bowel movement within a day of their first dose, but it can take up to a week of taking it twice daily to see the full effect. See our guide to lubiprostone 24 mcg dosing for what to expect.
What should I avoid while taking Amitiza?
Avoid taking it on an empty stomach, which makes nausea more likely. Tell your provider if you take methadone, which can make it less effective. Don’t take it if you have a known or suspected bowel obstruction or severe diarrhea.
Which is better, Linzess or Amitiza?
Neither is better for everyone. Amitiza (lubiprostone) is taken twice daily with food, and nausea is its most common side effect. Linzess (linaclotide) is taken once daily on an empty stomach, and diarrhea is its most common side effect. Many people try one, then switch if side effects or results aren’t right. Your provider can help you decide which to start with.
References
- FDA prescribing information — https://www.accessdata.fda.gov/drugsatfda_docs/label/2017/021908s015lbl.pdf
- Drugs.com — https://www.drugs.com/pro/amitiza.html
- GoodRx — https://www.goodrx.com/amitiza and https://www.goodrx.com/lubiprostone
- Drugs.com — https://www.drugs.com/availability/generic-amitiza.html
Bummed content is for general education and should never replace professional medical advice that considers your individual health. If you think you’re experiencing a medical emergency, call 911 or head to the nearest emergency department.
Prescription products require an online consultation with a physician who will determine if a prescription is appropriate.