Management of chronic constipation
Treatment of mild cases of constipation includes increasing the intake of fiber-rich foods like fruits, vegetables, whole grains and other lifestyle changes. In more severe conditions, patients may have to take medications to aid bowel regularity for constipation treatment.
The initial management of chronic constipation includes dietary changes, the use of laxatives (bulk-forming and/or non bulk-forming) or enemas. Most often in mild cases, medical intervention is not necessary. The use of dietary fibers such as pectin, inulin or resistant maltodextrin are the most physiologic and effective approach to managing such mild cases of constipation.
Commonly used over the counter (OTC) preparations for chronic constipation:
1. Dietary fibers
Mechanism of action:
There are 2 groups of dietary fibers: (1) soluble fibers, and (2) insoluble fibers. Both groups act differently to help with constipation. Soluble fibers, like Fibrosol, may increase the fecal stool bulk as well as soften it so that it slides easily through the large intestine, easing constipation. Click here to read more on the mechanisms of action for Fibrosol and how it helps with constipation. Insoluble fibers, on the other hand, adds bulk to fecal content in the large intestine to help with constipation.
Caution and side effects:
Although generally regarded as safe, taking excessive amounts of fiber may lead to local gastrointestinal issues such as bloating and passing of gas.
2. Lubricant laxative - Mineral oil (Lubricant Petrolatum)
Mechanism of action:
This lubricant laxative coats the bowel with a waterproof film to avoid the absorption of water from the stool. Thus, it encourages for easier bowel movement.
Caution and side effects:
Children below 6 years old should not use mineral oil to treat constipation. Only one mineral oil enema should be used per day. You should consult a physician if you experience rectal bleeding or did not have any bowel movement after using the mineral oil enema. If taken at higher doses, it may cause leakages into the rectum, which can lead to itching around the anus. Mineral oil enemas should not be used during pregnancy or for women planning for pregnancy, as it may inhibit vitamin absorption (for fat-soluble vitamins). Side effects of mineral oil are mild bloating, gas, diarrhea and stomach cramps.
3. Emollient laxative - Docusate Calcium or Sodium (Anionic Surfactant)
Mechanism of action:
These are also called stool softeners which helps manage constipation by allowing water and lipids to penetrate the stools, hence reducing the surface tensions. This can prevent the stools from being excessively dry and hard.
Caution and side effects:
Irritated throat, severe dizziness, trouble in breathing. The patient needs to discontinue the use of emollient laxatives if abdominal pain, GI bleeding, and vomiting occur.
4. Osmotic laxative - Polyethylene Glycol, Magnesium Hydroxide, Lactulose, Sorbitol, Magnesium Citrate
Mechanism of action:
Osmotic laxatives encourage bowel movement by engulfing water from surrounding body tissues, resulting in distention and promotes peristalsis.
Caution and side effects:
These can cause problems like bloating, diarrhea. Dehydration can occur for some people due to electrolyte imbalance, as osmotic laxatives draw out nutrients and other elements along with water.
5. Bulk-forming laxatives - Psyllium, Polycarbophil, Guar Gum, Methylcellulose, Malt Soup Extract
Mechanism of action:
These laxatives are not digested but absorbs the liquids from the intestine and swell to soften the stool. Due to the resulting bulk, the bowel is stimulated for bowel movement to occur.
Caution and side effects:
Stomach pain, bloating, intestinal blockage, skin rash, itchiness, difficulty swallowing and breathing may occur with the use of bulk-forming laxatives. However, they are known to be generally safe when taken at the prescribed doses.
6. Stimulant laxatives - Dehydrocholic Acid
Mechanism of action:
It induces and stimulates bowel movements by increasing the contraction of muscles in the intestines.
Caution and side effects:
These medications may cause urine to turn reddish-brown (note that they are usually a harmless side effect), nausea, diarrhea, weakness.
Prescription drugs for chronic constipation
These medications require a prescription by a doctor, and should only be taken with physician’s advice.
Linaclotide
It is approved by the U.S. Food and Drug Administration (FDA) for the treatment of Irritable Bowel Syndrome with Constipation (IBS-C) & Chronic Idiopathic Constipation (CIC) (i.e., no known causes for the constipation). Linaclotide is a peptide agonist which works by increasing the amount of fluid in the intestine. It increases smooth muscle contraction, thereby promoting bowel movement. The most common side effect of Linaclotide is diarrhea, abdominal pain, and flatulence. The U.S. FDA included a black box label warning to avoid use for children under 6 years old. Linaclotide should also be avoided in children and adolescent from 6 years to 18 years old due to the risk of serious dehydration.
Source: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=09beda19-56d6-4a56-afdc-9a77b70b2ef3
Lubiprostone
It is an oral bicyclic fatty acid approved by the U.S. FDA for treating chronic idiopathic constipation (CIC) in adults. It is also approved to treat irritable bowel syndrome with constipation (IBS-C) for women 18 years old and older. Lubiprostone is a prostaglandin derivative which activates CIC-2 chloride channels on gastrointestinal epithelial cells which produce chloride-rich fluid secretion. These secretions help to soften the stools and also increase spontaneous bowel movement. The most commonly reported adverse effects in clinical trials for lubiprostone were nausea, diarrhea, headache, and abdominal distention.
Source: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=222817c2-d4a6-43d0-8cbb-215f19acb198
Prucalopride Succinate
Prucalopride succinate is not approved by U.S. FDA, however, this is approved in Europe, Canada, and many other countries. Prucalopride is indicated for symptomatic treatment of chronic constipation in adults in whom laxatives fail to provide adequate relief. Prucalopride is a selective serotonin (5-HT4) receptor agonist, which improves gut motility. Adverse effects of the drug include headache, dizziness, tremors, palpitations, nausea, diarrhea, abdominal pain, vomiting.
Source: https://www.medicines.org.uk/emc/product/584/smpc
Methylnaltrexone
It is a U.S. FDA-approved narcotic drug used for treating opioid-induced constipation. Generally, it is used when the conventional laxatives failed. Methylnaltrexone acts as an antagonist on the opioid receptors. This drug does not cross the blood brain barrier and hence does not reverse the painkilling properties of opioids such as morphine. Common side effects are passing of gas, dizziness, hot flashes, tremor, and chills.
Source: https://www.rxlist.com/relistor-side-effects-drug-center.htm
Naloxegol Oxalate
Naloxegol is approved by the U.S. FDA as an oral tablet. Similar to methylnaltrexone, naloxegol oxalate is indicated for the treatment of opioid-induced constipation in adult patients with chronic non-cancer pain. The side effects of naloxegol include diarrhea, nausea/vomiting, passing of gas, and sweating/chills.
Source: https://www.accessdata.fda.gov/drugsatfda_docs/label/2014/204760s000lbl.pdf
Plecanatide
Plecanatide is approved by the U.S. FDA as an oral tablet, and belongs to the same class of medication as linaclotide, and is also indicated for the treatment of chronic idiopathic constipation (CIC) in adults. Plecanatide increases fluid secretion into the gastrointestinal tract, accelerating intestinal transit and causes changes in stool consistency. Diarrhea is the most common side effect of plecanatide.
Source: https://www.accessdata.fda.gov/drugsatfda_docs/label/2017/208745lbl.pdf