Lubiprostone is marketed by the brand name Amitiza. It is a locally acting drug that primarily activates the intestinal chloride channels and increases the fluid in the digested food, relieving constipation.
Unlike Trulance and Linzess (Plecanatide and Linaclotide), Amitiza (Lubiprostone) acts on the chloride channels and activates them. Trulance and Linzess are drugs used for the treatment of chronic constipation with a different mechanism of action.
Lubiprostone (Amitiza) is used to treat patients with constipation that has poorly responded to other over-the-counter medications. These include:
- Chronic idiopathic constipation,
- IBS with constipation, and
- Opioid-induced constipation.
What is Amitiza?
Amitiza is the brand name of Lubiprostone. It is a type of medicine that has strong laxative effects. It can help to ease constipation. It is also used to help ease symptoms of constipation dominant irritable bowel syndrome (IBS). It helps to relieve constipation and to make bowel movements more normal.
How Does Lubiprostone Help Constipation?
Lubiprostone (Amitiza) acts locally in the intestinal lumen and activates the chloride channel in the luminal epithelial cells. By activating the chloride channels, it increases the intestinal fluid without altering the serum sodium and potassium levels.
An increase in the intestinal fluid results in an increase in the intestinal peristaltic movements, relieving constipation. It is also thought to repair the mucosal epithelial lining and reduces intestinal permeability by increasing the synthesis of tight junctions and incorporating them in between the cells.
Lubiprostone increases the intestinal fluid by activating the apical chloride channels
What is chronic constipation?
As per the new Rome III Criteria, constipation is defined as bowel movements of three or less per week that persists for three or more months. It is usually associated with the sensation of fullness, straining, tenesmus, incomplete evacuation, and the passage of hard stools.
It is one of the most common bowel problems that affects an estimated 2 – 27% of people in the world. Constipation occurs when your digestive system produces slow transit of your stool, making it difficult for you to pass stool.
Chronic constipation is infrequent bowel movements for 3 months or more
Symptoms of constipation:
You might experience cramps in your lower belly. You might find that you are not able to fully empty your bowels. Your poop might be hard and dry. You might find it hard to pass the stools. You might notice blood in your stools. You might experience rectal bleeding.
What is the dosage of Amitiza (Lubiprostone)?
Amitiza is available in 8 mg and 24 mg capsules.
Amitiza dose in patients with chronic constipation:
For patients with chronic constipation, it is usually administered in a dose of 24 mg twice daily with food.
For individuals with hepatic impairment, the dose is reduced. It is then given as 16 mg twice daily in Child Class B and 8 mg twice daily in Child Class C hepatic impairment. However, the dose may be increased if there is an inadequate response.
In CIC, it is given in a dose of 24 mg twice daily
Amitiza dose in patients with constipation-dominant Irritable bowel Syndrome:
Amitiza is administered in a dose of 8 mg two times a day with food in patients with IBS-C. In patients with hepatic impairment, the dose is reduced. It is given as 8 mg once daily in patients with Child Class C liver disease. In moderate hepatic impairment, no dosage adjustment is necessary.
In IBS-C, it is given in a dose of 8 mg twice daily
What are the side effects of Amitiza?
The most common side effects of Lubiprostone (Amitiza) reported in clinical trials are Nausea, Diarrhea, and abdominal pain.
The most common side effects in patients treated for IBS-C with the lower dose of 8 mg twice daily is given in the chart below:
Side effects in patients treated for constipation were more since a higher dose of the drug was used in these patients. The most commonly reported side effects were primarily related to the gastrointestinal.
The percentage of patients who reported side effects in clinical trials when they were treated for chronic idiopathic constipation at a dose of 24 mg twice daily are tabulated here:
Systemic Side effects
|GI side effects||Nausea||29|
|CNS Side effects||Headache||11|
|General Side effects||Edema||3|
|Respiratory Side effects||Dyspnea||2|
Conditions when Lubiprostone should be avoided?
Amitiza should be avoided in patients who have a mechanical GI obstruction. It should also be avoided in dehydrated patients and those who are at a high risk of developing dehydration such as children who are six years of age or younger.
Amitiza use may be associated with shortness of breath. Although this is not a serious side effect of the drug, it should be evaluated. Shortness of breath could be a clue to an underlying serious disease of the lungs, heart, or other systems. It is therefore mandatory to discontinue using the drug and if the symptoms persist, evaluation is important.
Lubiprostone should not be given to pregnant females because of limited data and adverse fetal outcomes in animal studies. It is considered pregnancy class C medicine.
Avoid Amitiza in young children!
How effective is Amitiza (Lubiprostone)?
Lubiprostone has been studied in patients with constipation and IBS-C. Spontaneous bowel movements occurred in 56.7% to 62.9% of the individuals within 24 hours in individuals treated with Lubiprostone compared to individuals who were given a placebo medicine (31.9% to 36.9%).
In clinical trials conducted in patients with IBS-C, individuals who received Amitiza in a dose of 8 mg twice daily responded well to treatment compared to those who received placebo. The percentage of “overall responders” in the Amitiza group ranged from 12.1% to 13.8% compared to 5.7% to 7.8% in the placebo group.
Lubiprostone relieves constipation by increasing the amount of water and salt in your stool. For patients with irritable bowel syndrome, it does not cure the problem but instead helps keep the bowels regular. And, for chronic constipation including patients with opioid-induced constipation, Amitiza helps improve the symptoms by increasing the volume of stools.