| Dietary fiber/bulking agents |
Wheat bran Psyllium seed husk Methylcellulose |
Luminal water binding increases stool bulk and reduces consistency |
Flatulence and abdominal distension Stool impaction (rarely) Not recommended in frail, immobile, or palliative care patients |
| Osmotic laxatives |
| Undigestible disaccharides and sugar alcohols |
Lactulose Sorbitol |
Luminal water binding by creating an osmotic gradient |
Bloating, flatulence |
| Synthetic macromolecules |
PEG Polycarbophil |
Luminal water binding |
Bloating |
| Salinic laxatives |
Magnesium hydroxide (e.g., milk of magnesia) Magnesium citrate Magnesium sulfate Sodium phosfate |
Luminal water binding Increases fluid excretion |
Electrolyte imbalance (must be used with caution in patients with compromised renal or cardiac function) |
| Stimulant laxatives |
| Diphenylmethane derivatives |
Bisacodyl, sodium picosulfate |
Act locally to stimulate colonic motility, decrease water absorption from large intestine |
Abdominal discomfort and cramps |
| Anthraquinones |
Senna, aloe, cascara |
Act locally to stimulate colonic motility, decrease water absorption from large intestine |
Abdominal discomfort and cramps |
