Stimulant Laxative

Bisacodyl

A stimulant laxative given as tablets or suppositories for constipation and to empty the bowel before procedures.

Drug card

Class: Stimulant laxative
How it works: Stimulating the colon lining to push stool along and secrete water
Used for: Short-term relief of constipation
Emptying the bowel before surgery or colonoscopy
Known for: Abdominal cramps and pain

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Mechanism of action

How does bisacodyl work?

A diphenylmethane prodrug that esterases in the gut lining turn into the active BHPM. Acting locally on the colon and rectum, it triggers peristalsis and the secretion of water and salts. Enteric-coated tablets work in about 6 to 12 hours, and suppositories in about 10 to 45 minutes.

Like other stimulant laxatives: Stimulant laxatives are turned into their active forms in the gut and act directly on the lining of the large bowel. They set off propulsive contractions of the colon and make it secrete water and salts while absorbing less, so stool arrives sooner and softer: about 6 to 12 hours after a tablet, and within an hour after a bisacodyl suppository.

Uses

What is bisacodyl used for?

Short-term relief of constipation
Emptying the bowel before surgery or colonoscopy

Side effects

Side effects of bisacodyl

Abdominal cramps and painKnown for
Diarrhea
Nausea and vomiting
Dizziness or fainting, usually from straining
Mild blood in the stool
Ischemic colitis (rare)Serious
Low potassium with overuseSerious
DehydrationSerious
Allergic reactions, including angioedemaSerious

Known for marks what an exam expects you to know it for.

Watch for

Cautions and what sets it apart

Do not take the tablets with milk, antacids or PPIs: they dissolve the enteric coating too early.
Contraindicated with ileus or obstruction, acute abdominal conditions, acute inflammatory bowel disease and severe dehydration.
Daily use beyond 5 days calls for finding the cause; overuse brings fluid loss and low potassium.

Remember it

A way to remember it

Stimulant laxatives make the colon squeeze, and squeezing cramps.

Senna and bisacodyl act on the colon lining to trigger strong propulsive contractions and secretion, which is why abdominal cramps are their classic side effect.

Written for biofideX

Its class

Stimulant laxatives

Other stimulant laxatives with a card:

Senna

Easily mixed up with osmotic laxatives.

All about stimulant laxatives

Sources

Checked against

Written for biofideX in plain words, after checking these references:

For learning pharmacology, not for treatment decisions: no doses are given, and a prescriber, pharmacist or the product's own label is the word on any one patient. Spotted a mistake? Tell us and we'll correct it.

Practice it

Stomach and gut

Bisacodyl is one of 15 drugs practiced together here: their classes, how they work, what they treat and what they're known for.

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