How Do IBS Agents Work?

Irritable bowel syndrome (IBS) agents involve a combination of drug classes mainly used to treat IBS. IBS is a group of symptoms that typically affects the intestine. Some of the symptoms of IBS include:

• Abdominal pain or discomfort
• Alternating constipation and diarrhea
• Weight loss or anemia

IBS agents mainly aim to relieve the symptoms rather than the disease itself. Some of the commonly used drug classes of IBS agents are:

• Antispasmodics: In people with IBS, the muscles of the gastrointestinal tract (GI) contract abnormally due to the release of excess acetylcholine or calcium ions. Acetylcholine is a stimulatory neurotransmitter that acts on the muscles of the GI tract to induce contraction. It results in chronic pain and disturbances in bowel habits. Antispasmodic drugs either inhibit the action of acetylcholine or block calcium ions to prevent abnormal contraction.
• Antidepressants: They work to suppress the chronic pain associated with IBS.
• Drugs acting on opioid receptors: Opioid receptor agonists slow the GI and colonic transit and increase water absorption in the intestine. GI transit is the passage of food through the entire GI tract, whereas colonic transit is the passage of food through the colon. Opioid receptors delay the GI and colonic transit and increase water absorption from the intestine, thus reducing loose stools. Opioid receptor agonists also alleviate pain sensation, providing overall relief of symptoms.
• 5-HT3 receptor antagonists: 5-HT3 receptors are mainly found in the brain and the intestinal cells. People who have diarrhea as a symptom also have increased levels of serotonin in their blood. High serotonin levels can increase bowel reactions like cramps and diarrhea. 5-HT3 receptor antagonist drugs bind to the receptors and delay the passage of stomach contents in the colon (colonic transit).
• Intestinal secretagogues: They act via two mechanisms:
  • Chloride-channel activation: Drugs activating chloride channels in the intestine allow the movement of water and sodium inside the intestine. As a result, the stools become loose, and the transit is accelerated.
  • Sodium-hydrogen exchanger: These drugs allow the movement of sodium and water inside the intestine.

IBS agents are mainly given to treat the symptoms of irritable bowel syndrome. They include:

• Constipation
• Diarrhea
• Mixed diarrhea/constipation

IBS agents, when taken orally, can cause the following side effects:

• Constipation
• Abdominal pain
• Headache
• Nausea
• Fatigue
• Bloating
• Piles
• Acid reflux
• Muscle spasm
• Cough
• Diarrhea
• Vomiting

The information contained herein is not intended to cover all possible side effects, precautions, warnings, drug interactions, allergic reactions, or adverse effects. Check with your doctor or pharmacist to make sure these drugs do not cause any harm when you take them along with other medicines. Never stop taking your medication and never change your dose or frequency without consulting your doctor.

Generic and brand names of IBS agents include:

• Alosetron
• Amitiza
• Eluxadoline
• Ibsrela
• Linaclotide
• Linzess
• Lotronex
• Lubiprostone
• Plecanatide
• Tegaserod
• Tenapanor
• Trulance
• Viberzi
• Zelnorm