Amitiza Is a Prescription Medication Used to Treat Chronic Constipation, IBS-C, and Opioid-Induced Constipation in Adults

If your doctor has mentioned Amitiza — or you've been researching treatments for stubborn constipation — you probably have questions. What exactly is this medication? How does it work? What does it cost? This guide covers everything you need to know about Amitiza in 2026.

What Is Amitiza?

Amitiza is the brand name for Lubiprostone, a prescription medication in a class called chloride channel activators. It was originally developed and marketed by Takeda Pharmaceuticals (manufactured by Mallinckrodt Pharmaceuticals).

Amitiza is available as a soft gelatin capsule in two strengths:

• 8 mcg capsule
• 24 mcg capsule

It is not a controlled substance, which means it doesn't carry the prescribing restrictions that medications like opioids do. A generic version (Lubiprostone) became available after Amitiza's patent expired around 2024-2025.

To understand the science behind how it works, see our article on how Amitiza works.

What Is Amitiza Used For?

Amitiza is FDA-approved for three conditions:

1. Chronic Idiopathic Constipation (CIC) in Adults

"Chronic idiopathic constipation" means long-term constipation with no identifiable underlying cause. If you've had infrequent, difficult, or incomplete bowel movements for months and over-the-counter treatments haven't helped, your doctor may consider Amitiza.

2. Irritable Bowel Syndrome With Constipation (IBS-C) in Women 18 and Older

IBS-C is a type of irritable bowel syndrome where constipation is the primary symptom, often accompanied by bloating and abdominal pain. Amitiza is FDA-approved for IBS-C specifically in women aged 18 and older. It has not been sufficiently studied in men with IBS-C for that indication.

3. Opioid-Induced Constipation (OIC) in Adults With Chronic Non-Cancer Pain

Opioid medications are well-known for causing constipation. If you take opioids for chronic pain (not related to cancer) and standard laxatives aren't enough, Amitiza can help restore more normal bowel function.

How Is Amitiza Taken?

Amitiza is taken orally, twice daily, with food and water. Here are the standard doses by condition:

• Chronic idiopathic constipation: 24 mcg twice daily
• IBS-C in women: 8 mcg twice daily
• Opioid-induced constipation: 24 mcg twice daily

Important: Swallow the capsules whole. Do not break or chew them. Taking Amitiza with food is important — it significantly reduces the risk of nausea, which is the most common side effect.

If you have liver problems, your doctor may prescribe a lower dose. For moderate hepatic impairment with CIC, the typical adjusted dose is 16 mcg twice daily. For severe hepatic impairment, it may be reduced to 8 mcg twice daily.

Who Should Not Take Amitiza?

Amitiza is not appropriate for everyone. You should not take it if you have:

• Known or suspected mechanical bowel obstruction — If something is physically blocking your intestine, Amitiza will not help and could be dangerous.
• Allergy to Lubiprostone — If you've had an allergic reaction to Lubiprostone or any ingredient in Amitiza capsules.

Pregnancy Warning

Amitiza should not be used during pregnancy. Animal studies showed fetal loss at the recommended human dose. If you could become pregnant, your doctor should:

• Confirm a negative pregnancy test before prescribing
• Advise you to use effective contraception during treatment

If you become pregnant while taking Amitiza, stop the medication and contact your doctor immediately.

Other Cautions

• Nursing mothers — It's not known whether Lubiprostone passes into breast milk. Discuss risks and benefits with your doctor.
• Children — Amitiza has not been studied in pediatric patients.
• Liver disease — Dose adjustments are needed (see above).

For a full list of medications to be cautious about while taking Amitiza, read our guide on Amitiza drug interactions.

How Much Does Amitiza Cost?

Cost is a real consideration with this medication:

• Brand-name Amitiza: $400 to $530 for a 30-day supply (60 capsules of 24 mcg)
• Generic Lubiprostone: $60 to $150 for a 30-day supply

The availability of generic Lubiprostone has made this medication significantly more affordable for many patients. However, not all pharmacies stock the generic, so you may need to shop around.

Insurance Coverage

Most insurance plans cover Amitiza or its generic, but often require:

• Prior authorization — Your doctor needs to get approval from your insurance before they'll pay for it.
• Step therapy — Your insurance may require you to try cheaper alternatives first (like Polyethylene Glycol or Docusate) before covering Amitiza.

Brand Amitiza is typically Tier 3 or specialty tier on most formularies. Generic Lubiprostone may be Tier 2, with a lower copay.

Ways to Save

There are several ways to bring down the cost:

• Ask your pharmacist for the generic (Lubiprostone) instead of brand Amitiza
• Use prescription discount cards from GoodRx, SingleCare, or RxSaver
• Check if you qualify for the Mallinckrodt Patient Assistance Program
• Look into NeedyMeds and RxAssist for additional financial help

For a complete breakdown, see our guide on how to save money on Amitiza.

Final Thoughts

Amitiza is a well-established treatment for chronic constipation, IBS-C, and opioid-induced constipation. With generic Lubiprostone now available, it's more accessible and affordable than ever. If you think Amitiza might be right for you, talk to your doctor about whether it fits your symptoms and medical history.

Ready to fill your prescription? Use Medfinder to find a pharmacy near you that has Amitiza in stock.