Can Trulance (plecanatide) and Amitiza (lubiprostone) be taken together?

Can Trulance and Amitiza Be Taken Together?

There is no specific contraindication to taking Trulance (plecanatide) and Amitiza (lubiprostone) together, but combining these medications is not recommended in routine clinical practice because both are intestinal secretagogues that work through similar mechanisms and would likely result in additive side effects—particularly severe diarrhea—without clear evidence of additional benefit.

Mechanistic Considerations

Both medications increase intestinal fluid secretion, though through different pathways:

• Plecanatide is a guanylate cyclase-C agonist that increases chloride and bicarbonate secretion, primarily acting in the proximal small bowel 1, 2
• Lubiprostone activates type-2 chloride channels on the apical membrane of epithelial cells throughout the GI tract 3, 4

The overlapping mechanism of action (both increase intestinal fluid secretion) makes combination therapy pharmacologically redundant and increases the risk of excessive fluid secretion leading to severe diarrhea and potential dehydration.

Evidence-Based Treatment Approach

The 2023 AGA-ACG guidelines for chronic idiopathic constipation provide clear guidance on pharmacological management but do not recommend or discuss combination therapy with multiple secretagogues 5. The guidelines made:

• Strong recommendations for plecanatide and conditional recommendations for lubiprostone as monotherapy options
• No mention of combining secretagogues, suggesting this is not standard practice

Safety Concerns with Combination

Diarrhea Risk

• Diarrhea is the most common adverse event for plecanatide (reported in ~5% of patients) 6, 7
• Lubiprostone's most common side effects include nausea (up to 31%), diarrhea, and headache 3
• Combining these agents would substantially increase the risk of severe diarrhea, which is already the primary reason for discontinuation of either medication 5

Additional Considerations

• Post-marketing surveillance data shows diarrhea as the most frequently reported adverse event across all secretagogues, with potential for clinically significant dehydration 8
• The FDA label for Trulance specifically warns about severe diarrhea and advises stopping the medication if this occurs 1

Clinical Practice Algorithm

If a patient has inadequate response to one secretagogue:

1. First: Optimize the current medication dose and ensure adequate trial duration (at least 4 weeks)
2. Second: Switch to a different class of medication rather than adding another secretagogue:
   • Consider prucalopride (5-HT4 agonist) - different mechanism 5
   • Consider osmotic laxatives (PEG, magnesium oxide) if not already tried 5
   • Consider stimulant laxatives for rescue therapy 5
3. Third: If switching within secretagogues, discontinue the first agent before starting the second

Bottom Line

Do not combine Trulance and Amitiza. If one secretagogue is ineffective, switch to the other or choose a medication from a different class. The lack of any published data supporting combination secretagogue therapy, combined with the predictable increase in diarrhea risk, makes this combination clinically inadvisable. The 2023 guidelines support sequential monotherapy approaches rather than polypharmacy with agents having overlapping mechanisms 5.