BICOLEX ENTERIC COATED TABLETS

Indications

• Constipation
• Bowel preparation for surgical procedures
• Bowel preparation for diagnostic tests

Dosage

Children: For children aged 6 to 12 years, the recommended dose is 5-10 mg orally once

Adults: The usual adult dose is 5-15 mg orally, taken once daily.

Mechanism of action

Bisacodyl is deacetylated to the active form, bis-(p-hydroxyphenyl)-pyridyl-2-methane (BHPM), by intestinal deacetylase. BHPM stimulates parasympathetic nerves in the colon, increasing motility and secretions. It stimulates adenylate cyclase, which raises cyclic AMP levels, leading to the active transport of chloride and bicarbonate out of cells. This process causes sodium, potassium, and water to leave the cells passively, while preventing reabsorption of sodium and chloride ions. By decreasing the expression of aquaporin 3, bisacodyl reduces water movement into the vasculature, contributing to increased water content in the colon. It also directly stimulates the colonic mucosa, enhancing peristaltic contractions.

Pharmacodynamics

Bisacodyl has a wide therapeutic index, allowing for flexible dosing between 5-15 mg orally. It is important for patients to be aware of potential side effects such as abdominal pain, nausea, vomiting, or prolonged changes in bowel function exceeding two weeks. In case of rectal bleeding or no bowel movement within 12 hours, patients are advised to discontinue use and consult a healthcare provider.

Pharmacokinetics

Bisacodyl is rapidly absorbed in the gastrointestinal tract and then metabolized to its active form in the intestine. Its onset of action varies depending on the route of administration; oral doses typically take 6 to 12 hours for effect, while rectal administration may act more quickly, within 15 minutes to 1 hour. The drug's effects are localized primarily to the colon, with minimal influence on small intestinal motility.

Adverse effects

• Abdominal pain
• Nausea
• Vomiting
• Electrolyte imbalances
• Diarrhea
• Rectal bleeding

Precautions

• Counsel patients regarding potential abdominal pain, nausea, vomiting, or a change in bowel function lasting longer than 2 weeks
• Advise discontinuation if rectal bleeding occurs or no bowel movement is observed within 12 hours
• Use with caution in patients with known gastrointestinal disorders

Pregnancy

Bisacodyl should be used during pregnancy only if clearly needed. Consult a healthcare professional before use.

Breast-feeding

Bisacodyl is excreted in breast milk. Consult a healthcare professional before use while breastfeeding.

Storage

Store at room temperature, away from moisture and heat. Keep out of reach of children.

Formulations

• Oral tablets
• Suppositories

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 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. Water is also be transported from the luminal side of cells into the vasculature by aquaporin 3. Bisacodyl decreases expression of aquaporin 3, preventing water from moving into the vasculature, which may contribute to increased water in the colon. Bisacodyl directly stimulates parasympathetic nerves in the colon, stimulating contraction of longitudinal smooth muscle but not circular smooth muscle. Bisacodyl is a stimulant laxative, ... acting directly on the colonic mucosa-where it stimulates sensory nerve endings to produce parasympathetic reflexes resulting in increased peristaltic contractions of the colon. The contact action of the drug is restricted to the colon, and motility of the small intestine is not appreciably influenced. /Bisacodyl/ increases water retention in the stool by coating surfaces of stool and intestines with a water-immisicible film. Lubricant effect eases passage of contents through intestines. Emulsification of lubricant tends to enhance its ability to soften stool mass. /Laxatives/ Recent studies show that these drugs alter fluid and electrolyte absorption producing net intestinal fluid accumulation and laxation. Some of these drugs may directly stimulate active intestinal ion secretion. Increased concentrations of cyclic 3',5'-adenosine monophosphate (cAMP), occurring in colonic mucosa 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/ Bisacodyl caused dose-dependent contractions in isolated guinea pig ileum & taenia coli which was not prevented by atropine or pheniramine. It prevented acetylcholine- & histamine-induced contractions. Bisacodyl-induced contractions were not caused by a decrease in endogenous cyclic amp level. However, both endogenous cyclic amp & verapamil (a calcium transport inhibitor) inhibited bisacodyl-induced contractions, suggesting site of action on calcium-dependent contractile system of smooth muscle cells. Intestinal secretagogues as well as the laxative, bisacodyl, raise the K+ efflux rate across the mucosal border by 200-300%. Results suggest that laxatives may increase rate of K+ secretion into the colonic lumen by raising the K+ permeability of the mucosal border.

Pharmacodynamics

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.