Constipation%20in%20adults%20-%20chronic%20functional Treatment

• Treatment should be instituted primarily to obtain regular and complete bowel movements and secondarily to palliate symptoms of anorexia, bloating, and abdominal pain
• Efficacy, safety and drug dependency should all be considered when deciding on which laxative to use
  • Bulk-producing and osmotic laxatives are generally the 1st choice
  • Other agents for management of chronic constipation may be considered after a therapeutic trial of fiber supplementation and laxatives

Bulk-Producing Laxatives

• Eg Ispaghula (Psyllium), Methylcellulose, Sterculia, Calcium polycarbophil 
• Increases bulk of stool and increases gastrointestinal motility
• Psyllium has been shown to increase stool frequency in patients with chronic constipation
• Therapy should be started with 2 daily doses in the morning and evening with fluids; dose may be adjusted after 7-10 days
• Patients should be informed that immediate response should not be expected and that bloating and abdominal distension may occur especially at the start of fiber therapy but may decrease over time or with a dose reduction

Osmotic Laxatives

• Eg Lactulose, Macrogol/Polyethylene glycol (PEG), Milk of Magnesia, Sorbitol, Na chloride, Na phosphate
• Poorly absorbed or non-absorbed substances which cause secretion of water into the intestines osmotically increasing intraluminal fluids that ease transport of colonic content
• Osmotic laxatives may be attempted if an increase in fiber or use of bulk-producing laxatives fails to relieve symptoms
• Lactulose has been shown to be effective at increasing stool frequency and stool consistency in patients with chronic constipation
  • May have a prebiotic effect ie growth of colonic probiotic bacteria is supported that could bring about bowel function improvement
• PEG has been demonstrated in a Cochrane analysis to be superior to Lactulose in patients with chronic constipation; it is also useful for fecal disimpaction in the elderly
• Combination therapy may also be considered with either a stimulant or an enterokinetic agent (eg Prucalopride) plus an osmotic agent
• Patients may be instructed to adjust dose so that soft, but not liquid stools, are achieved and that these agents may take several days to work

Stimulant Laxatives

• Eg Bisacodyl, Na picosulfate, Senna, Glycerin
• Active metabolites have both secretory and anti-absorptive effects increasing intestinal motility
  • Glycerin or Bisacodyl suppository causes local rectal stimulation thus inducing defecation
• Work within hours but may cause abdominal cramps
• Long-term oral use of stimulant laxatives should be avoided
• Short-term use of Senna is considered safe during pregnancy and no increased risk of congenital abnormalities was observed with its use during pregnancy

Enemas

• Distend the colon thus inducing stool evacuation
• Aid in the treatment of fecal impaction
  • Cleansing enema or short-term stimulant laxative can be used to relieve symptoms
  • Bulk-producing or osmotic laxative may then be used to maintain bowel patency
• May be considered in patients who have failed all other treatment measures 
• Avoid in patients at risk of fluid or electrolyte imbalance eg individuals with cardiac or renal disease, elderly

Other Laxatives

• Stool softener eg Docusate sodium
• Lubricant eg Mineral oil

Other Agents for Constipation

Secretagogues

• Eg Lubiprostone, Linaclotide, Plecanatide
• Stimulate chloride and fluid secretion into the intestinal lumen accelerating small bowel and colon transit
• These agents have no arrhythmic effects

Prokinetic Agent

• Eg Prucalopride
• A selective serotonin [5-hydroxytryptamine (5-HT₄)] receptor agonist which accelerates colonic transit time
• Effective in patients with severe chronic constipation refractory to conventional laxatives
• Has demonstrated no significant adverse cardiac side effects in large trials
  • May be given to elderly patients and those with stable cardiovascular disease

Ileal Bile Acid Transporter Inhibitor

• Eg Elobixibat
• Enhances bile acid supply in the proximal colon where it induces secretory and motor effects

Probiotics

• Bifidobacterium lactis DN173010, Lactobacillus casei Shirota, and Lactobacillus casei YIT were shown, in a systematic review, to improve stool consistency and increase stool frequency in patients with chronic constipation
• Use of probiotics appears promising; however, further studies are needed prior to recommending a specific probiotic strain or preparation for the treatment of functional constipation