Table 1.
Main types of pharmacologic laxatives
| Type | Agents | Mechanism of action | Most common adverse events |
| Bulking agents | Psyllium | Increase in stool bulk and reduction in consistency by luminal water binding | Bloating |
| Methylcellulose | Flatulence | ||
| Calcium polycarbophil | |||
| Stool softeners | Docusate potassium | Softening and lubrication of stools by increasing water secretion | Nausea |
| (surfactants) | Docusate sodium | Vomiting | |
| Docusate calcium | Abdominal pain/cramps | ||
| Rectal urgency | |||
| Osmotic laxatives | Milk of Magnesia (magnesium hydroxide) | Osmotic water retention, decreased stool consistency, and increase fecal volume and peristalsis | Sweet taste |
| Magnesium citrate | Nausea | ||
| Magnesium sulphate | Bloating | ||
| Sodium picosulphate/magnesium citrate (Picoprep®) | Flatulence | ||
| Lactulose/lactilol | Abdominal pain/cramps | ||
| Sorbitol | Electrolyte disturbances (?) | ||
| Polyethylene glycol (macrogol) | |||
| Stimulant laxatives | Anthraquinones | Luminal water retention through activation of CAMP, and induction of colonic contractions by acting on enteric nerves | Abdominal pain/cramps |
| Senna | Dehydration | ||
| Cascara | Electrolyte disturbances | ||
| Bisacodyl | Muscle cramps | ||
| Phenolphthalein | Melanosis coli/colonic inertia (?) |
CAMP: Cyclic adenosine monophosphate.