From the Guidelines
Linaclotide is the most recommended medication for IBS-C, due to its strong recommendation and high certainty in the evidence of effects, as stated in the 2022 AGA clinical practice guideline 1. For IBS-C (Irritable Bowel Syndrome with Constipation), several effective medication options are available.
First-line Treatments
- Fiber supplements like psyllium (Metamucil) at 3-12g daily in divided doses, which adds bulk to stool and improves transit.
- Osmotic laxatives such as polyethylene glycol (MiraLAX) at 17g daily dissolved in water can be used regularly without significant tolerance concerns.
Prescription Medications
- Linaclotide (Linzess) at 290mg once daily is the most recommended option, as it increases intestinal fluid secretion and accelerates transit, with a strong recommendation and high certainty in the evidence of effects 1.
- Lubiprostone (Amitiza) at 8mcg twice daily with food is another option that works by increasing intestinal fluid, although it has a conditional recommendation and moderate certainty 1.
- Plecanatide (Trulance) at 3mg once daily is a newer agent with similar effects to linaclotide but potentially fewer side effects.
- Tegaserod (Zelnorm) at 6mg twice daily may be considered for women under 65 without cardiovascular risk factors. These medications work through different mechanisms - some draw water into the intestine, while others increase gut motility or fluid secretion.
Dosage and Administration
Start with the lowest effective dose and adjust based on response, as diarrhea can be a side effect of many of these medications. Patients should take these medications consistently rather than intermittently for optimal symptom control.
From the FDA Drug Label
Lubiprostone is indicated for the treatment of irritable bowel syndrome with constipation (IBS-C) in women at least 18 years old. LINZESS is a guanylate cyclase-C agonist indicated for treatment of: Irritable bowel syndrome with constipation (IBS-C) in adults.
The medications lubiprostone and linaclotide are useful for IBS-C 2 3.
- Lubiprostone is indicated for women at least 18 years old.
- Linaclotide is indicated for adults.
From the Research
Medications for IBS-C
- Linaclotide is a useful medication for the treatment of irritable bowel syndrome with constipation (IBS-C) 4, 5, 6, 7, 8
Mechanism of Action
- Linaclotide acts as a potent guanylate cyclase C receptor agonist, stimulating fluid secretion, increasing colonic transit, and reducing abdominal pain 4, 5, 8
Efficacy
- Linaclotide has been shown to be effective in increasing weekly spontaneous bowel movements and complete spontaneous bowel movements, as well as reducing abdominal pain in patients with IBS-C 4, 5, 7
Safety
- The most common adverse event associated with linaclotide is diarrhea, which is generally mild and confined to the gastrointestinal tract 4, 5, 6
Dosage
- Linaclotide is approved for oral once-daily administration at doses of 145 μg for chronic constipation and 290 μg for IBS-C 5