Table 1:

Characteristics of treatments of chronic constipation in older people

Category; mechanism	Treatment	Dose	Adverse effects
Osmotic agents Increase water content in colon to maintain isotonicity with plasma	Polyethylene glycol	17–34 g/d	Bloating, flatulence, abdominal pain, diarrhea
	Lactulose	15–30 mL daily to twice daily	Bloating, flatulence, abdominal pain, diarrhea
	Sorbitol	15–30 mL daily to twice daily	Bloating, flatulence, abdominal pain, diarrhea
	Magnesium hydroxide	15–30 mg daily to twice daily	Hypermagnesemia, bloating, flatulence, abdominal pain, diarrhea
	Sodium phosphate	10–25 mL with 350 mL of water	Hyperphosphatemia, hypocalcemia, hypernatremia and hypokalemia, bloating, flatulence, abdominal pain, diarrhea
Bulk agents Fibre retains water, which increases fecal mass, stimulating peristalsis	Psyllium	Up to 20 g/d	Bloating, flatulence; rarely cases of mechanical obstruction and allergic reactions
	Methylcellulose	Up to 20 g/d	Bloating, flatulence
	Polycarbophil	Up to 20 g/d	Bloating, flatulence
Stimulants Increase intestinal motility	Sennoside	Up to 68.8 g/d in divided doses	Abdominal cramps, hypokalemia, pseudomelanosis coli
	Bisacodyl	5–10 mg/d orally or rectally	Abdominal cramps, hypokalemia, pseudomelanosis coli
Stool softeners Decrease stool surface tension leading to increased water penetration	Dioctyl sodium sulfosuccinate or docusate	100 mg twice daily	Abdominal cramps, diarrhea
	Docusate calcium	240 mg twice daily	Abdominal cramps, diarrhea
Prokinetic agents Stimulates 5-HT4 intestinal receptors, inducing peristalsis	Prucalopride	2 mg/d	Nausea, vomiting, flatulence, headache
Enemas or suppositories Enemas distend the rectum to initiate the defecation reflex; they also soften stool	Phosphate-based enema	120 mL/d	Hyperphosphatemia and other electrolyte disturbances
	Tap-water enema	500 mL/d
	Glycerin suppository	Once daily

Note: 5-HT₄ = 5-hydroxytryptamine-4.

Source: Lembo and Camilleri.⁴²