Constipation is a common complaint, based on the definition – either self-reported or using Rome criteria – chronic constipation can affect from 2-27% of the population.1 Many misconceptions surround bowel habits and what is normal, leading to misdiagnoses and overuse of laxatives.2 When patients consult pharmacists for assistance with bowel complaints, it is critical that you are fully aware of different options for treating and preventing constipation. 

Causes 

There are many factors that contribute to or cause constipation, often by altering transit time. According to the Canadian Society of Intestinal Research these can include:  

• medication side effects (e.g., some narcotics, antidepressants, codeine, calcium or iron supplements, and medications that affect the nervous system), 
• diseases in which there is a physiological change to some tissue or organ of the body (e.g., radiation therapy, inflammatory bowel disease, colon cancer, diabetes, stroke, hypothyroidism, or Parkinson’s disease), 
• functional disorders, such as irritable bowel syndrome, intestinal obstructions or strictures resulting from surgery, and 
• diet and lifestyle choices, such as consuming a diet too low in fibre and fluid, insufficient physical activity, and chronic use of laxatives, suppositories, or enemas.³ 
• Older age is also a factor according to Cleveland Clinic. “Older people tend to be less active, have a slower metabolism and less muscle contraction strength along their digestive tract than when they were younger,” they said. 
• Being a woman. “Especially while you are pregnant and after childbirth,” Cleveland Clinic explained. “Changes in a woman’s hormones make them more prone to constipation. The baby inside the uterus squishes the intestines, slowing down the passage of stool.”⁴ 

Symptoms 

Symptoms of constipation can vary depending on the patient and whether the constipation is chronic or temporary. The Southern Cross Medical Care Society highlights the following symptoms: 

• Passing fewer than three stools a week 
• Having dry, lumpy, or hard stools 
• Straining to a have bowel movement 
• Having a feeling that there's a blockage in your rectum that is preventing a bowel movement 
• Having a feeling that a stool can’t be completely emptied from your rectum5 
• bloated abdomen⁶ 
• abdominal cramps⁶ 

Most complications result from the intense straining needed to pass stool. These can include haemorrhoids, faecal impaction, anal fissures, bright red streaks on the stool, and rectal prolapse.^1,6 

Treatment 

For most patients with constipation, treatment should focus on dietary change and exercise rather than laxatives, enemas, and suppositories, none of which really address the underlying problem. It’s important to increase the intake of dietary fibre and fluid, exercise daily, and reduce consumption of foods and drinks that cause constipation.^5,6 

If constipation does not improve with diet, then there are supplements and medications available: 

• Bulk forming agents (fibres, e.g. psyllium, sterculia): absorb liquid in the intestines and swell to form a soft bulky stool, the presence of which stimulates bowel movement. While not quick-acting, they are safe for long-term use.^3,5 
• Enemas and suppositories (e.g. sodium citrate, glycerol, phosphate enemas): help to soften stools and produce a bowel movement.³ 
• Lubricant laxatives (e.g. paraffin liquid): coat the colon and stool in a waterproof film, allowing it to remain soft and slip easily through the intestine, usually within 6-8 hours.^3,5 
• Stimulant laxatives (e.g. sennoside B, bisacodyl): increase muscle contractions to move food along the digestive tract more quickly. Stimulants are typically recommended for short-term use.^3,5 
• Hyperosmotics (osmotic laxatives): encourage bowel movements by drawing water into the bowel from nearby tissue (intestinal lumen), thereby softening stool.3,5 Some of these laxatives can cause electrolyte imbalances if they draw out too many nutrients and other substances with the water. They can increase thirst and dehydration. The Canadian Gastrointestinal Society (CGS) list the following four main types of hyperosmotics:³ 
  • Saline laxatives are salts dissolved in liquid; “they rapidly empty all contents of the bowel, usually working within 30 minutes to three hours. Examples of saline laxatives are citrate salts, magnesium preparations, sulphate salts, and sodium phosphate. They are not intended for long-term use or for pregnant women.” 
  • Lactulose laxatives are “sugar-like agents that work similarly to saline laxatives but at a much slower rate and are sometimes used to treat chronic constipation. They take six hours to two days to produce results”. 
  • Polymer laxatives consist of large molecules that cause the stool to hold and retain water. “They are usually non-gritty, tasteless, and are well tolerated for occasional constipation. Results can be expected within six hours, but it can take longer depending on the dose. An example of a polymer laxative is polyethylene glycol.” 
  • Glycerine is available as a suppository and mainly has a hyperosmotic effect, but it may also have a stimulant effect from the sodium stearate used in the preparation.⁵ 
• Prokinetic agents (e.g. prucalopride): trigger and normalise bowel motions. Their use is restricted to people with severe constipation. ^3,5 

REFERENCES: 

1. Sanchez MI, Bercik P. Epidemiology and burden of chronic constipation. Can J Gastroenterol. 2011 Oct;25 Suppl B(Suppl B):11B-15B. doi: 10.1155/2011/974573. PMID: 22114752; PMCID: PMC3206560. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3206560/ 
2. Allen, S. (2007). ‘How to deal with constipation’. Available from: https://pharmaceutical-journal.com/article/ld/how-to-deal-with-constipation  
3. BadGut. ‘Constipation.’ Available from: https://badgut.org/information-centre/a-z-digestive-topics/constipation/ 
4. Southern Cross. ‘Constipation: Symptoms and Treatment.’ Available from:  https://www.southerncross.co.nz/group/medical-library/constipation-symptoms-treatment 
5. Cleveland Clinic. ‘Constipation.’ Available from: https://my.clevelandclinic.org/health/diseases/4059-constipation 
6. Better Health. ‘Constipation.’ Available from: https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/constipation