Action

Unclear. Thought to stimulate colonic mucosa, producing parasympathetic reflexes that enhance peristalsis and increase water and electrolyte secretion, thereby causing evacuation of colon.

Availability

Enema: 0.33 mg/ml, 10 mg/ml

Powder for rectal solution: 1.5 mg bisacodyl and 2.5 g tannic acid

Suppositories (rectal): 5 mg, 10 mg

Tablets (enteric-coated): 5 mg

Indications and dosages

➣ Constipation; bowel cleansing for childbirth, surgery, and endoscopic examination

Adults and children ages 12 and older: 5 to 15 mg P.O. or 10 mg P.R. as a single dose

Children older than age 3: 5 to 10 mg or 0.3 mg/kg P.O. as a single dose

Children ages 2 and older: 5 to 10 mg P.R. as a single dose

Children younger than age 2: 5 mg P.R. as a single dose

Contraindications

• Hypersensitivity to drug

• Intestinal obstruction

• Gastroenteritis

• Appendicitis

Precautions

Use cautiously in:

• hypersensitivity to tannic acid

• severe cardiovascular disease, anal or rectal fissures

• pregnant or breastfeeding patients.

Administration

• Make sure patient swallows tablets whole without chewing.

• Don't give tablets within 1 hour of dairy products or antacids (may break down enteric coating).

• Know that drug should be used only for short periods.

Adverse reactions

CNS: dizziness, syncope

GI: nausea, vomiting, diarrhea (with high doses), abdominal pain, burning sensation in rectum (with suppositories), laxative dependence, protein-losing enteropathy

Metabolic: hypokalemia, fluid and electrolyte imbalances, tetany, alkalosis

Musculoskeletal: muscle weakness (with excessive use)

Interactions

Drug-drug. Antacids: gastric irritation, dyspepsia

Drug-diagnostic tests. Calcium, magnesium, potassium: decreased levels

Phosphate, sodium: increased levels

Drug-food. Dairy products: gastric irritation

Patient monitoring

• Assess stools for frequency and consistency.

• Monitor patient for electrolyte imbalances and dehydration.

Patient teaching

• Instruct patient to swallow (not chew) enteric-coated tablets no sooner than 1 hour before or after ingesting antacids or dairy products. Tell him not to chew tablets.

• Advise patient not to use bisacodyl or other laxatives habitually because this may lead to laxative dependence.

• Suggest other ways to prevent constipation, such as by eating more fruits, vegetables, and whole grains to increase dietary bulk and by drinking 8 to 10 glasses of water daily.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, and foods mentioned above.