Bisacodly is a diphenylmenthane stimulant laxative. The tannic acid present in the bisacodly tannex complex precipitates protein and its astringent effect decreases mucous secretion in the large intestine. Tannic acid also facilitates adherence of contrast media to mucous membranes. Tannic acid increases evacuation of the colon. Stimulant laxatives alter fluid and alectrolyte absorption, producing net intestinal fluid accumulation and laxation.
Some of these drugs may directly stimulate active intestinal ion secretion. Increased concentration of cyclic 3’,5’-adenosine monophosphate (cAMP), occurring in colonic mucosal cells following administration of stimulant laxatives, may alter the permeability of these cells and mediate active ion secretion thereby producing net fluid accumulation and laxative action. Stimulant laxatives mainly promote evacuation of the colon.
Following oral or rectal administration Bisacodly is converted to the active desacetyl metabolite bis(p-hydroxyphenyl)pyridyl-2-methane by intestinal and bacterial enzymes. Absorption from the gastro-intestinal tract is minimal with enteric-coated tablets, the small amount absorbed is excreted in the urine as the glucuronide. Bisacodly is mainly excreted in the faeces
Bisacodly is a laxative used for the treatment of constipation and for bowel evacuation before investigational procedures or surgery. It is usually effective within 6-12 hours after oral doses.
Dosage and administration
Adults and children over 10 years: 5-10 mg at bedtime.
Children aged between 4 and 10 years: should only be given if recommended by the doctor
Usual doses: 5 mg at bed time
Children under 4 years: not recommended
Contraindications and warnings
As with other laxatives, prolonged use should be avoided. Bisacodly should not be given to patients with intestinal obstruction or acute abdominal conditions such as appenditis; care should also be taken in patients with inflammatory bowel disease. It should not be used in patients with severe dehydration.
Bisacodly and other stimulant laxatives may cause abdominal discomfort such as colic or cramps. Prolonged use or overdosage can result in diarrhea with excessive loss of water and electrolytes, particularly Potassium; there is also the possibility of developing an atonic non-functioning colon.
By increasing intestinal motility, all laxatives may potentially decrease transit time of concomitantly administered oral drugs and thereby decrease their absorption. In particular, tell your doctor or pharmacist if you are taking:
- Diuretics such as bendroflumethiazide or furosemide
- Steroid medicines such as prednisolone.