Can you take Linzess and Bentyl together? What to know about the interaction

October 10, 2025 •

4 min read

Approximately 10 to 15 percent of the global population is affected by irritable bowel syndrome (IBS), a condition for which medications like Linzess and Bentyl are frequently prescribed. However, the question of whether you can take Linzess and Bentyl together is complicated by their fundamentally opposing mechanisms of action, requiring careful consideration and medical advice.

Quick Summary

Taking Linzess and Bentyl together is medically complex because their opposing effects on intestinal movement can reduce Linzess's effectiveness. Linzess speeds up the gut to treat constipation, while Bentyl slows it down to relieve cramps. Combining these prescriptions necessitates a doctor's careful evaluation to balance symptom management and mitigate risks like severe diarrhea.

Key Points

Conflicting Actions: Linzess increases gut motility for constipation, while Bentyl decreases it for cramping, making them functionally contradictory.
Reduced Effectiveness: Taking Bentyl can decrease the effectiveness of Linzess by counteracting its primary function of accelerating bowel movements.
Risks of Combined Use: Combining the drugs can cause unpredictable and possibly severe side effects, including both severe diarrhea and worsened constipation.
Medical Supervision is Essential: Any combined use of Linzess and Bentyl must be carefully managed and supervised by a healthcare professional.
Different Symptom Focus: These medications are typically prescribed for different primary symptoms of IBS: Linzess for constipation-dominant issues (IBS-C) and Bentyl for pain and spasms.

Understanding Linzess: A Guanylate Cyclase-C Agonist

Linzess (linaclotide) is a medication approved to treat irritable bowel syndrome with constipation (IBS-C) and chronic idiopathic constipation (CIC) in adults. Its mechanism of action is unique; as a guanylate cyclase-C (GC-C) agonist, it works by increasing the concentration of cyclic guanosine monophosphate (cGMP) in the intestines. This surge in cGMP triggers the secretion of chloride and bicarbonate into the intestinal lumen, increasing fluid volume in the intestines. The added fluid helps to soften stools and speed up transit time, leading to more frequent and easier bowel movements. The most common side effect of Linzess is diarrhea, which can sometimes be severe. Other side effects include abdominal pain, gas, and bloating.

Understanding Bentyl: An Anticholinergic Agent

Bentyl (dicyclomine) is an older medication used to treat the symptoms of IBS, particularly abdominal pain and cramping caused by muscle spasms in the gut. It belongs to a class of drugs called anticholinergics, which work by blocking the action of acetylcholine. Acetylcholine is a neurotransmitter that helps stimulate muscle contractions in the gastrointestinal tract. By blocking this, Bentyl relaxes the smooth muscles of the intestines, reducing spasms and alleviating the associated pain. Common side effects of Bentyl include dry mouth, dizziness, blurred vision, and drowsiness. A potentially serious side effect is constipation, as the medication intentionally slows down bowel motility.

The Conflicting Mechanisms of Linzess and Bentyl

The central issue with combining Linzess and Bentyl lies in their fundamentally contradictory effects on the digestive system. While Linzess is designed to increase intestinal fluid and accelerate bowel motility to relieve constipation, Bentyl actively slows down intestinal movement to alleviate spasms. Taking an anticholinergic drug like Bentyl can counteract the therapeutic effect of Linzess, making the Linzess less effective than usual. This is because Bentyl's motility-slowing action directly opposes Linzess's motility-accelerating action, essentially pitting the two medications against each other.

Risks and Considerations for Combined Use

While no major drug interactions are consistently documented, the physiological conflict between Linzess and Bentyl means they are generally not prescribed together for routine use. If a physician decides to do so, it would be under close supervision and likely for very specific reasons, such as managing severe cramping alongside persistent constipation that is not fully addressed by Linzess alone. The potential consequences include:

Reduced efficacy: Bentyl could inhibit the fluid-increasing and motility-promoting effects of Linzess, leaving the patient with unresolved constipation.
Exacerbated side effects: Combining these drugs could create a push-pull effect, potentially causing unpredictable changes in bowel habits. Bentyl can cause constipation, while Linzess can cause diarrhea, making it difficult to find the right balance.
Masked symptoms: The conflicting actions could mask whether either medication is working effectively. For example, if diarrhea from Linzess is counteracted by constipation from Bentyl, it becomes hard to assess the benefit of each.
Increased risk of dehydration: The potential for severe diarrhea from Linzess, especially if not well-monitored, carries a risk of dehydration that could be complicated by other gastrointestinal issues.

Comparison Table: Linzess vs. Bentyl


Feature	Linzess (Linaclotide)	Bentyl (Dicyclomine)
Mechanism of Action	Increases fluid secretion by activating guanylate cyclase-C.	Relaxes smooth muscle by blocking acetylcholine receptors (anticholinergic).
Primary Symptom Treated	Constipation, including IBS-C and CIC.	Abdominal pain and cramping in IBS.
Effect on Bowel Motility	Increases intestinal transit time.	Decreases intestinal motility.
Interaction with other drug	Effectiveness may be reduced by Bentyl.	Can counteract the effects of Linzess.
Common Side Effects	Diarrhea, abdominal pain, bloating, gas.	Dry mouth, dizziness, blurred vision, constipation.

Consulting Your Doctor

Because of the conflicting pharmacological actions, it is critical to consult with a healthcare professional before taking these two medications together. They can assess your specific symptoms and determine the most appropriate treatment plan. In some cases, a physician may recommend using them at different times or prioritizing one medication over the other to manage your predominant symptoms. A doctor might also consider alternative strategies or dosages to minimize the risks of reduced efficacy and unwanted side effects.

Conclusion

While Linzess and Bentyl may both be used for irritable bowel syndrome, their opposing actions on the gastrointestinal tract make them generally unsuitable for combined use. Linzess is a pro-motility agent for constipation, while Bentyl is an anti-motility agent for cramps. Attempting to manage both issues simultaneously with these drugs can lead to therapeutic conflicts and potentially unpredictable side effects, such as a worsening of either constipation or diarrhea. The decision to combine these medications, if necessary, should only be made by a healthcare provider who can carefully weigh the risks and benefits and closely monitor the patient for adverse effects or lack of efficacy.

Frequently Asked Questions

The primary conflict is that Linzess speeds up the gut to treat constipation, while Bentyl slows it down to relieve cramps. Their opposing mechanisms can negate each other's effects, potentially rendering one or both medications less effective.

Yes, Bentyl can make Linzess less effective. Because Bentyl is an anticholinergic that slows down intestinal motility, it directly counteracts the action of Linzess, which increases fluid and speeds up movement to relieve constipation.

Common side effects of Linzess include diarrhea, abdominal pain, gas, and bloating. Diarrhea is the most common and can be severe in some cases.

Common side effects of Bentyl include dry mouth, dizziness, blurred vision, and drowsiness. Because it slows bowel motility, it can also cause constipation.

Linzess is specifically prescribed for IBS with constipation (IBS-C) because it addresses the core issue of slow bowel movement. Bentyl is prescribed for IBS with pain and cramping because it relaxes the muscles that cause spasms.

In some rare situations, a doctor might prescribe these medications together under very careful supervision. This is not a typical approach and would be to address very specific symptom combinations that a single medication cannot treat.

If you are currently taking both medications, you should discuss your treatment plan with your doctor. Do not stop or change your dosages without medical supervision, as a healthcare professional can best manage the conflicting effects to find an optimal solution for your symptoms.