Laxatives vary widely in how long they take to work and how long their effects last, depending on the type:
- Suppositories and enemas act the fastest, typically within 15 to 30 minutes, sometimes up to 1 hour.
- Stimulant laxatives (e.g., bisacodyl, senna) usually produce effects in about 6 to 12 hours, with the active ingredients metabolized over roughly 16 hours.
- Lubricant laxatives (e.g., mineral oil) work within 6 to 8 hours.
- Bulk-forming laxatives (e.g., psyllium) generally take 12 to 24 hours for initial effects, with full effects up to 48 to 72 hours; they work by adding bulk and are eliminated with the next bowel movement, so they don't have a half-life.
- Osmotic laxatives can vary widely: saline types act quickly in 30 minutes to 6 hours, while others like lactulose take 48 to 72 hours.
- Emollient (stool softener) laxatives take about 12 to 72 hours to work, sometimes up to 3 days or more.
In general, laxatives provide short-term relief and are recommended for use only a few days (typically 2 to 3 days) to avoid harm to the intestines. The duration of laxative action depends on the active ingredient, dose, and route of administration, with effects lasting from minutes to several days after a single dose
. Summary table of onset times:
Type of Laxative| Time to Effect
---|---
Suppositories/enemas| 15 to 30 minutes (up to 1 hour)
Stimulant| 6 to 12 hours
Lubricant| 6 to 8 hours
Bulk-forming| 12 to 24 hours (initial), up to 72 hours (full)
Osmotic| 30 minutes to 3 days (varies by type)
Emollient (stool softener)| 12 to 72 hours (up to 3 days)
The laxative effect typically diminishes after the stool is passed, and the active substances are metabolized or eliminated from the body within hours to a couple of days
