Classifications: gi stimulant, laxative;
Therapeutic: laxative, gi stimulant

Prototype: Bisacodyl
Pregnancy Category: C


325 mg tablets; liquid


Acts principally in large intestine by stimulating propulsive movements of colon through direct chemical irritation. Casanthrol, which is present in a variety of OTC mixtures, is a derivative of cascara sagrada.

Therapeutic Effect

Effective laxative with results in 6–12 h. Useful in conditions where straining at stool is to be avoided.


Temporary relief of constipation and to prevent straining at stool in various disease conditions. Sometimes used with milk of magnesia.


Abdominal pain, fecal impaction; GI bleeding, ulcerations; appendicitis, gastroenteritis, intestinal obstruction, CHF; pregnancy (category C).

Cautious Use

Lactation; renal impairment; diabetic patients; rectal bleeding; concomitant laxative use.

Route & Dosage

Adult: PO Tablet: 325–1000 mg/d; fluid extract: 0.5–1.5 mL/d; aromatic fluid extract: 2–6 mL/d
Child: PO 2–12 y, ? of adult dose; <2 y, 1/4 of adult dose
Infant: PO Aromatic fluid extract: 1.25 mL/d as single dose


  • Administer with a full glass of water on an empty stomach for best results. Results may be delayed somewhat by food.
  • Store in tightly covered, light-resistant containers, unless otherwise directed by manufacturer.

Adverse Effects (≥1%)

GI: Anorexia, nausea, gripping, abnormally loose stools, constipation rebound, melanosis of colon. Metabolic: Hypokalemia, impaired glucose tolerance, calcium deficiency. Urogenital: Discoloration of urine.

Diagnostic Test Interference

Possibility of interference with PSP excretion test because of urine discoloration.


Drug: Decreased effect of oral anticoagulants.


Absorption: Minimal from GI tract. Onset: 6–12 h. Metabolism: In liver. Elimination: In feces and urine; excreted in breast milk.

Nursing Implications

Assessment & Drug Effects

  • Monitor electrolyte balance if significant diarrhea occurs, especially with frail older adults.
  • Monitor restoration of normal bowel function.

Patient & Family Education

  • A single dose taken before retiring usually results in evacuation of soft stool 6–12 h later.
  • Frequent or prolonged use of irritant cathartics disrupts normal reflex activity of colon and rectum and can lead to drug dependence for evacuation.
  • See bisacodyl for additional information.

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug

© 2006-2023 Last Updated On: 02/01/2023 (0)
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