Description
PHARMACOLOGICAL PROPERTIES:
Pharmacodynamic properties:
Mechanism of action
Bisacodyl is deacetylated to the active bis-(p-hydroxyphenyl)-pyridyl-2-methane (BHPM) by an intestinal deacetylase. BHPM can stimulate parasympathetic nerves in the colon directly to increase motility and secretions.
Bisacodyl is deacetylated to the active bis-(p-hydroxyphenyl)-pyridyl-2-methane (BHPM) by an intestinal deacetylase. BHPM can stimulate parasympathetic nerves in the colon directly to increase motility and secretions.
Bisacodyl stimulates adenylate cyclase, increasing cyclic AMP, leading to active transport of chloride and bicarbonate out of cells. Sodium ions, potassium ions, and water passively leave the cell; while sodium and chloride ions are unable to be reabsorbed.
Pharmacodynamic effects
Patients should be counselled regarding abdominal pain, nausea, vomiting, or a change in bowel function that lasts longer than 2 weeks. It has a wide therapeutic index, as patients can take 5-15 mg orally. Patients taking bisacodyl should be counselled before taking the medication if they are already experiencing abdominal pain, nausea, vomiting, or a change in bowel function lasting longer than 2 weeks. Patients should also be counselled to stop taking the medication if they experience rectal bleeding or no bowel movement in 12 hours.
Pharmacokinetic properties:
Absorption
Oral formulations of bisacodyl are only 16% bioavailable. A 10 mg enteric coated oral tablet reaches a Cmax of 26 ng/mL with a Tmax of 8 hours, while a 10 mg oral solution reaches a Cmax of 237 ng/mL with a Tmax of 1.7 hours. A 10 mg suppository reaches a Cmax of 0-64 ng/mL.
In lactating women, 10mg of oral bisacodyl reaches a Cmax of 20.5-195 ng/mL, with a Tmax of 3-4 hours, and a geometric mean AUC after a single dose of 471 h*ng/mL. After multiple doses, the geometric mean AUC decreases to 311 h*ng/mL.
Distribution
Volume of distribution of the active metabolite, BHPM, in lactating women is 181 L after a single dose and 289 L at steady state.
Metabolism
Bisacodyl is deacetylated to the active bis-(p-hydroxyphenyl)-pyridyl-2-methane (BHPM) by an intestinal deacetylase. A small amount of BHPM is absorbed from the gastrointestinal tract, and is glucuronidated before elimination.
Elimination
The majority of bisacodyl is eliminated in the feces. 13.8-17.0% of a bisacodyl dose is eliminated in the urine as the active metabolite BHPM.
THERAPEUTIC CLASS: Laxatives
CLINICAL PARTICULARS:
Therapeutic Indication:
- For the short-term relief of occasional constipation.
Posology and method of Administration:
Posology:
Adults (including the elderly) and children over 12 years: 1 to 2 coated tablets (5 – 10 mg) daily.
Method of administration
For oral administration:
The tablets should be swallowed whole with an adequate amount of fluid.
Missed Dose:
If one dose is missed, this dose should be omitted and the next dose should be taken at the usual time. Do not take a double dose to make up for a forgotten dose.
CONTRAINDICATIONS:
- Bisacodyl is contraindicated in patients with ileus, intestinal obstruction, acute abdominal conditions including appendicitis, acute inflammatory bowel diseases, and severe abdominal pain associated with nausea and vomiting which may be indicative of the aforementioned severe conditions.
- Bisacodyl is also contraindicated in severe dehydration and in patients with known hypersensitivity to Bisacodyl.
SIDE EFFECTS:
Anaphylactic reactions, angioedema, hypersensitivity, Dehydration, dizziness, abdominal pain, diarrhoea and nausea.
SPECIAL WARNINGS AND PRECAUTIONS FOR USE:
- As with all laxatives, bisacodyl should not be taken on a continuous daily basis for more than five days without investigating the cause of constipation.
OTHER MEDICINES AND BISACODYL TABLETS:
The effect of the following drugs can be influenced (interactions):
- The concomitant use of antacids and milk containing products may reduce the resistance of the tablet coating and result in dyspepsia and gastric irritation.
- The concomitant use of diuretics or adreno-corticosteroids may increase the risk of electrolyte imbalance if excessive doses of Bisacodyl are taken.
- Electrolyte imbalance may lead to increased sensitivity to cardiac glycosides.
PREGNANCY AND BREAST-FEEDING
Pregnancy: Use is recommended only if it is clearly needed.
Breast-feeding: This medicine is excreted in the milk the patients who are breast-feeding should consult with their healthcare provider.
DRIVING AND USING MACHINES
Patients should be advised that due to a vasovagal response (e.g. to abdominal spasm) they may experience dizziness and / or syncope. If patients experience abdominal spasm they should avoid potentially hazardous tasks such as driving or operating machinery.
OVER DOSE:
- If high doses are taken watery stools (diarrhoea), abdominal cramps and a clinically significant loss of fluid, potassium and other electrolytes can occur.
- Laxatives when taken in chronic overdose may cause chronic diarrhoea, abdominal pain, hypokalaemia, secondary hyperaldosteronism and renal calculi. Renal tubular damage, metabolic alkalosis and muscle weakness secondary to hypokalaemia have also been described in association with chronic laxative abuse.
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