Learn about Amitiza drug interactions including opioids, supplements, and OTC medications. Know what to avoid and what to tell your doctor.
Before starting any new medication, it's important to understand how it might interact with other drugs you're already taking. The good news about Amitiza (Lubiprostone) is that it has fewer drug interactions than many prescription medications. But there are still some important ones to know about.
This guide covers the medications, supplements, and substances that can interact with Amitiza — and what you should tell your doctor before starting treatment.
Drug interactions happen when one medication affects how another one works. This can happen in several ways:
With Amitiza, the most relevant concern is medications that may reduce its effectiveness — particularly certain opioids.
Diphenylheptane opioids, especially Methadone
This is the most significant drug interaction with Amitiza. Methadone and similar diphenylheptane opioids can block ClC-2 chloride channel activation — the exact mechanism Amitiza uses to work. This means if you take Methadone alongside Amitiza, the medication may not be effective at relieving your constipation.
If you're on Methadone for pain management or opioid use disorder and need treatment for constipation, talk to your doctor. They may recommend an alternative like Movantik (Naloxegol) or another approach that works through a different mechanism.
Other opioid medications
While Amitiza is specifically FDA-approved for opioid-induced constipation (OIC), other opioids may partially reduce its effectiveness. Common opioids to be aware of include:
This doesn't mean you can't take Amitiza with these medications — in fact, treating OIC is one of its approved uses. But your doctor should know exactly which opioid you're on and at what dose so they can monitor your response and adjust if needed.
One of the advantages of Amitiza is that it does not have significant interactions through the CYP450 enzyme system, which is the pathway where most drug interactions occur. This means Amitiza is less likely to interfere with medications processed by your liver, including:
That said, you should still tell your doctor about every medication you take — no exceptions.
If you're already taking over-the-counter laxatives or stool softeners like Docusate (Colace), Polyethylene Glycol (Miralax), Bisacodyl (Dulcolax), or Senna (Senokot), talk to your doctor before adding Amitiza. While there aren't formal drug interactions, combining multiple medications that increase intestinal fluid or motility can increase your risk of:
Your doctor may want you to stop OTC laxatives when you start Amitiza, or they may have you use them together strategically.
Fiber supplements like Psyllium (Metamucil) and Methylcellulose (Citrucel) are generally safe to take with Amitiza. However, if you're experiencing bloating or gas as a side effect, adding fiber on top may worsen those symptoms. Discuss timing and dosing with your doctor.
There are no known significant interactions between Amitiza and common antacids or acid reducers like Omeprazole (Prilosec), Famotidine (Pepcid), or calcium carbonate (Tums). These are generally considered safe to take together.
Probiotics are not known to interact with Amitiza. Many patients take both without issue, though the evidence on probiotics for constipation is mixed.
Amitiza has no specific food contraindications. In fact, taking it with food is recommended — it significantly reduces the risk of nausea, the most common side effect.
There are no known interactions with:
The main food-related guidance is simple: eat something before or with each dose. A small meal or snack is enough.
To minimize the risk of interactions and ensure Amitiza works safely for you, share the following information with your doctor:
Include:
If you start a new medication after you've already been taking Amitiza, tell both your prescriber and your pharmacist. This includes new prescriptions from other doctors, new OTC medications, and new supplements.
Your pharmacist is an excellent resource for checking drug interactions — they have access to interaction databases and can flag potential issues when filling your prescriptions.
Amitiza has a relatively clean drug interaction profile compared to many prescription medications. The main concern is with Methadone and certain opioids that may reduce its effectiveness. Beyond that, it avoids the CYP450 pathway, which means fewer surprises when combined with other common medications.
The most important thing you can do is be open with your doctor about everything you're taking. A complete medication list takes two minutes to share and can prevent serious problems down the road.
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