Dicyclomine vs. Linzess: What’s the difference?

What is dicyclomine? What is Linzess?

Dicyclomine is an anticholinergic used to treat irritable bowel syndrome (IBS). Anticholinergic drugs block the effects of acetylcholine, the chemical transmitter that nerves release in order to cause muscles to contract. They prevent contraction of muscles by blocking the acetylcholine receptors on the muscle cells. Anticholinergic drugs also have a direct relaxing effect on muscle. Dicyclomine is used to reduce contraction of the muscles in the intestines.

Linzess (linaclotide) is a guanylate cyclase-C agonist used to treat symptoms of irritable bowel syndrome (IBS) with constipation and chronic constipation of unknown cause (idiopathic constipation). Linzess works locally in the intestine (it is not absorbed into the body) to increase bowel movements and reduce pain. Linzess’ effects are due to an increase in the production of a chemical called cyclic guanosine monophosphate which increases fluid secretion into the intestine and reduces the sensitivity of pain-sensing nerves.


Digestive Disorders: Common Misconceptions See Slideshow

What are the side effects of dicyclomine and Linzess?


Common side effects include:

Other important side effects include:


The most common side effects of linaclotide are:

  • diarrhea,
  • stomach pain,
  • gas, and
  • stomach distention.

Linaclotide should be stopped if patients develop severe diarrhea. Other important side effects include:

Rarely, patients may experience passage of blood from the rectum.

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What is the dosage of dicyclomine vs. Linzess?


The recommended starting oral dose of dicyclomine is 20 mg given 4 times daily. The dose can be increased to 40 mg 4 times daily. The recommended intramuscular injection is 10 to 20 mg 4 times daily. The intramuscular injection is only used for 1 to 2 days if a patient cannot take capsules or tablets.


The dose for treating IBS with constipation is 290 mcg once daily, and the dose for treating chronic idiopathic constipation is 145 mcg once daily. Linaclotide should be taken on an empty stomach at least 30 minutes before the first meal of the day.

What drugs interact with dicyclomine and Linzess?


Antiglaucoma Agents

Anticholinergics antagonize the effects of antiglaucoma agents and may increase intraoccular pressure. Anticholinergic drugs in the presence of increased intraocular pressure may be hazardous when taken concurrently with agents such as corticosteroids. Use of Bentyl in patients with glaucoma is not recommended.

Other Drugs with Anticholinergic Activity

The following agents may increase certain actions or side effects of anticholinergic drugs including Bentyl:

Other Gastrointestinal Motility Drugs

Interaction with other gastrointestinal motility drugs may antagonize the effects of drugs that alter gastrointestinal motility, such as metoclopramide.

Effect of Antacids

Because antacids may interfere with the absorption of anticholinergic agents including Bentyl, simultaneous use of these drugs should be avoided.

Effect on Absorption of Other Drugs

Anticholinergic agents may affect gastrointestinal absorption of various drugs by affecting on gastrointestinal motility, such as slowly dissolving dosage forms of digoxin; increased serum digoxin concentration may result.

Effect on Gastric Acid Secretion

The inhibiting effects of anticholinergic drugs on gastric hydrochloric acid secretion are antagonized by agents used to treat achlorhydria and those used to test gastric secretion.


Drug interaction studies have not been conducted.


What is irritable bowel syndrome or IBS? See Answer

Are dicyclomine safe to use while pregnant or breastfeeding?


There are no adequate studies of the effect of dicyclomine in pregnant women at recommended doses (80-160 mg/day). Observation of women who received dicyclomine (up to 40 mg/day) containing products during the first trimester of pregnancy did not reveal any increased risk of harm to the fetus.

Dicyclomine is excreted into breast milk. Since there have been reports of apnea (cessation of breathing) when dicyclomine has been given to children, it should not be used by nursing mothers.


Linaclotide has not been adequately evaluated in pregnant women.

It is not known whether linaclotide is excreted in human milk. It is unlikely that linaclotide is excreted in breast milk because it is poorly absorbed and therefore undetectable in blood at recommended doses.

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Medically Reviewed on 11/7/2019


FDA Prescribing Information

Section on dicyclomine interactions courtesy of the U.S. Food and Drug Administration