bisacodyl
Brand: Dulcolax, Correctol
Prototype Drug
Drug Class: stimulant laxative
Drug Family: GI agent
Subclass: diphenylmethane stimulant laxative
Organ Systems: gastrointestinal
Mechanism of Action
After deacetylation by intestinal bacteria and mucosal esterases to the active form (BHPM), stimulates the colonic mucosa via irritation of the myenteric plexus, increasing peristaltic contractions and promoting fluid and electrolyte accumulation in the colon.
colonic epithelial cells (via deacetylation to BHPM)
Indications
- constipation
- bowel preparation before procedures
- postoperative constipation
Contraindications
- intestinal obstruction
- acute abdomen
- inflammatory bowel disease (flare)
- abdominal pain of unknown origin
Adverse Effects
Common
- abdominal cramping
- nausea
- diarrhea
- rectal irritation (suppository)
Serious
- electrolyte imbalances (chronic use)
- melanosis coli (long-term use)
- laxative dependence
Pharmacokinetics (ADME)
| Absorption | minimally absorbed from GI tract (<5%); enteric-coated tablets designed to release in colon |
| Distribution | low systemic exposure |
| Metabolism | converted in colon to active BHPM by bacterial enzymes |
| Excretion | primarily fecal |
| Half-life | short |
| Onset | 6–12 hours (oral); 15–60 minutes (rectal) |
| Peak | varies |
| Duration | varies |
| Protein Binding | minimal |
| Vd | minimal |
Drug Interactions
| Drug / Agent | Mechanism | Severity |
|---|---|---|
| milk or antacids | premature dissolution of enteric coating if taken within 1 hour | moderate |
| diuretics | additive electrolyte depletion with chronic use | moderate |
Nursing Considerations
- Do not crush or chew enteric-coated tablets; do not administer within 1 hour of milk, antacids, or acid-suppressing agents.
- Intended for short-term use only; chronic use leads to laxative dependence and electrolyte imbalances.
- Monitor electrolytes (sodium, potassium) with repeated use, particularly in elderly patients.
- Educate patients that suppository onset is 15–60 minutes; optimal timing is prior to planned defecation.
Clinical Pearls
- Bisacodyl is a commonly used component of bowel prep protocols (e.g., for colonoscopy) due to its reliable and predictable colonic stimulation.
- Melanosis coli — brownish discoloration of the colonic mucosa — can develop with chronic stimulant laxative use and is visible on colonoscopy; it is generally benign and reversible.
Safety Profile
Pregnancy avoid
Lactation generally-safe
Renal Adjustment Not required
Hepatic Adjustment Not required
TDM Not required
Concordance Terms
Cross-referenced clinical concepts — click any term to see all content where it appears.