|ATC code||A06AB02 (WHO) A06AG02 (WHO)|
|Biological half-life||16 Hours|
|Excretion||primarily in the feces, systemically absorbed drug is excreted in the urine|
|Chemical and physical data|
|Molar mass||361.391 g/mol|
|3D model (Jmol)||Interactive image|
|(what is this?)|
Bisacodyl (INN) is an organic compound that is used as a laxative drug. It works directly on the colon to produce a bowel movement. It is typically prescribed for relief of constipation and for the management of neurogenic bowel dysfunction as well as part of bowel preparation before medical examinations, such as for a colonoscopy.
Bisacodyl is marketed under the trade names Dulcolax/Durolax, Fleet, Nourilax, Alophen, Correctol, and Carter's Little Pills (formerly Carter's Little Liver Pills) as well as being available generically. It is usually sold as 5 mg tablets, 10 mg suppositories, or 5 mg pediatric suppositories. It is also available as a 1.25 US fluid ounces (37 ml) prepackaged enema containing a 10 mg delivered dose of liquid bisacodyl.
When bisacodyl is administered orally, it is usually taken at bedtime. Oral administration is known to produce no action for more than eight hours and then to work suddenly and relatively quickly. This is especially true if more than 10 milligrams is taken at one time. Normally the dosage is 5 or 10 milligrams, but up to 30 milligrams can be taken for complete cleansing of the bowel before a procedure. If taken at the maximum dosage, there will likely be a sudden, extremely powerful, uncontrollable bowel movement and so precautions should be taken. It is not recommended to take bisacodyl within one hour of taking an antacid or milk, as this may destroy the tablet coating and irritate the stomach. If taken too late in the evening, the action of this drug can start during sleep with undesirable results.
When administered rectally in suppository form, it is usually effective in 15 to 60 minutes. Two suppositories can be inserted at once if a very strong, purgative, enema-like result is needed. A few hours after the initial evacuation, there can be a secondary action which will continue as long as there is unexpelled bisacodyl present in the rectum.
As a small commercially prepared enema, it is usually effective in 5 to 20 minutes.
Mechanism of action
Bisacodyl works by stimulating enteric nerves to cause colonic contractions. It is also a contact laxative; it increases fluid and salt secretion. Action of bisacodyl on small intestine is negligible; stimulant laxatives mainly promote evacuation of the colon.
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- Robert Engelhorn, Ernst Seeger and Jan H. Zwaving "Laxatives" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2000. doi:10.1002/14356007.a15_183