Generic Name

Dulcolax

Mechanism

Dulcolax contains the active ingredient bisacodyl, a stimulant laxative.
• Direct stimulation of enteric nerves and interstitial cells of Cajal in the distal colon.
• Induces smooth‑muscle contraction and increases bowel motility.
• Stimulates secretion of water and electrolytes, enhancing stool volume.
• Onset of action: 15–60 min after oral ingestion; 5–15 min after rectal administration.

Pharmacokinetics

• Absorption: ~60–80 % of oral dose is absorbed; bioavailability ≈ 1 % (first‑pass glucuronidation limits systemic exposure).
• Distribution: Low protein binding; penetrates mucosa to reach intestinal smooth muscle.
• Metabolism: N‑glucuronidation in the liver → inactive metabolites.
• Elimination: Primarily excreted unchanged in feces; minimal renal excretion.
• Half‑life: 15–19 h (shorter for rectal use).
• Special populations: No dose adjustment needed for mild–moderate hepatic impairment; cautious use in severe hepatic disease.

Indications

• Acute constipation and fecal impaction.
• Preoperative bowel cleansing (short‑term, <72 h).
• Decongestive proctologic preparations (e.g., hemorrhoid evaluation).
• Brief postoperative gut motility stimulation.

Contraindications

Contraindications
• Mechanical bowel obstruction or suspected perforation.
• Active inflammatory bowel disease (e.g., Crohn’s, ulcerative colitis) until disease quiescent.
• Severe electrolyte disturbances or dehydration.

Warnings
• Diarrhea & cramping can precipitate electrolyte imbalance (hypokalemia, hyponatremia).
• Prolonged use (>3 days): risk of refractory constipation, dependency, and electrolyte depletion.
• Pregnancy & lactation: Category C; use only if benefit outweighs risk.
• Elderly & renal disease: Monitor stool output and serum electrolytes.

Dosing

Guidelines
• Start at the lowest effective dose.
• If stool is not achieved in 24 h, consider increased dose or alternate route.
• Do not exceed 4 mg/day orally or 2 mg/day rectally.

Adverse Effects

Common
• Abdominal cramping, bloating.
• Nausea, mild vomiting.
• Diarrhea (often watery).
• Flatulence.

Serious
• Severe electrolyte disturbances (hypokalemia, hyponatremia).
• Pseudomembranous colitis (secondary to Clostridioides difficile).
• Bowel perforation (rare, usually with underlying pathology).
• Hypersensitivity reactions (rash, urticaria, anaphylaxis).

Monitoring

• Electrolytes (K⁺, Na⁺) if use >48 h or in at-risk patients.
• Stool frequency & consistency (aim for 2–3 bowel movements/day).
• Signs of obstruction: abdominal pain, distension, vomiting.
• Renal function: not routinely but in patients on diuretics or with renal impairment.

Clinical Pearls

1. Dual‑route strategy: For severe constipation, combine a low oral dose with a single rectal dose to maximize peristaltic effect while limiting systemic exposure.

2. Electrolyte protection: Pair short‑term bisacodyl therapy with oral rehydration solutions containing potassium to mitigate hypokalemia risk.

3. Avoid polypharmacy: Do not co‑administer with other stimulants (e.g., senna, magnesium hydroxide) without monitoring, as synergistic effects can cause life‑threatening colonic spasm.

4. Pregnancy prudence: In the 3rd trimester, bisacodyl has been associated with increased uterine contractility; use only under obstetric supervision if benefit clear.

5. Elderly caution: Reduced colonic motility and comorbidities heighten risk of electrolyte derangement—use the lowest effective dose and monitor serum potassium.

6. Drug interactions: Bisacodyl may alter absorption of oral medications by increasing GI transit; separate dosing times by at least 1 hour when possible.

7. Contraindication sign-off: If signs of abdominal distention or pain appear, discontinue bisacodyl immediately and assess for potential obstruction or perforation.

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• *All information is current as of 2026 and may evolve with emerging evidence. For individualized patient care, refer to up‑to‑date prescribing information and professional guidelines.*