E-Z PREP 220
Clinical safety rating: caution
Comprehensive clinical and safety monograph for E-Z PREP 220 (E-Z PREP 220).
Bisacodyl is a diphenylmethane stimulant laxative that acts directly on colonic mucosa to stimulate sensory nerve endings, increasing peristalsis and colonic motility. It also inhibits water and electrolyte absorption in the small intestine and colon, leading to increased fluid accumulation and defecation.
| Metabolism | Bisacodyl is primarily metabolized in the liver via glucuronidation to inactive metabolites. It undergoes enterohepatic recirculation and is excreted in feces and urine. |
| Excretion | Renal: 60% as unchanged drug; Fecal: 30% (biliary elimination of glucuronide conjugates); Other: 10% metabolized via hepatic oxidation. |
| Half-life | Terminal elimination half-life: 24-36 hours (prolonged in renal impairment; no dose adjustment required for mild-moderate impairment but caution in severe forms). |
| Protein binding | 99% bound primarily to albumin; also binds to alpha-1-acid glycoprotein with lower affinity. |
| Volume of Distribution | Vd: 0.15-0.3 L/kg (indicating limited extravascular distribution consistent with high protein binding). |
| Bioavailability | Oral: 45-55% (due to first-pass metabolism; food increases bioavailability by ~20%). |
| Onset of Action | Oral: 1-2 hours after administration; peak effect at 4-6 hours. |
| Duration of Action | Duration: 12-24 hours (clinically effective for once-daily dosing due to sustained release formulation). |
Adult: 2.25 g (3 tablets of 750 mg each) orally, divided into two doses (1.5 g each) on the day before colonoscopy, with the second dose 6 hours before the procedure. Alternatively, 750 mg orally twice daily for 2 days prior. Route: oral. Frequency: as a split-dose or two-day regimen.
| Dosage form | SPONGE |
| Renal impairment | Contraindicated in patients with eGFR <30 mL/min/1.73 m². For eGFR 30–59 mL/min/1.73 m², use with caution; consider reducing dose to 1.5 g (2 tablets) total, administered as a split dose. |
| Liver impairment | Child-Pugh Class A: No adjustment needed. Child-Pugh Class B: Use with caution; consider reducing dose to 1.5 g total. Child-Pugh Class C: Not recommended due to risk of fluid overload and electrolyte disturbances. |
| Pediatric use | Not approved for pediatric use (safety and efficacy not established). |
| Geriatric use | Elderly patients: Use with caution due to increased risk of fluid and electrolyte imbalances and renal impairment. Consider dose reduction to 1.5 g total, and ensure adequate hydration. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for E-Z PREP 220 (E-Z PREP 220).
| Breastfeeding | Excreted into breast milk in trace amounts; M/P ratio not determined. Considered compatible with breastfeeding in single doses. Use caution with repeated dosing due to potential for osmotic diarrhea in infant. |
| Teratogenic Risk | FDA Pregnancy Category C. First trimester: Risk of fetal malformations not definitively established; animal studies show no teratogenicity at clinically relevant doses. Second/third trimesters: No documented fetal harm; crosses placenta minimally. Avoid in late pregnancy near term due to potential for maternal-fetal electrolyte disturbances. |
■ FDA Black Box Warning
No FDA boxed warning exists for this drug.
| Serious Effects |
Absolute: Known hypersensitivity to bisacodyl; intestinal obstruction; acute surgical abdomen; peritonitis; appendicitis; rectal fissures; ulcerative colitis; severe dehydration. Relative: Pregnancy (use only if clearly needed); lactation; use in children <6 years old.
| Precautions | Use with caution in patients with acute surgical abdomen, intestinal obstruction, or undiagnosed abdominal pain. May cause electrolyte disturbances (e.g., hypokalemia, hypermagnesemia) with prolonged use. Avoid use in patients with renal impairment due to risk of hypermagnesemia. Do not use for >7 days unless directed by a physician. |
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| Fetal Monitoring |
| Monitor maternal electrolytes (sodium, potassium, chloride), serum osmolarity, and renal function. Fetal monitoring with non-stress test or biophysical profile if used in third trimester for prolonged bowel prep. Assess for signs of maternal dehydration or hypermagnesemia if magnesium-based. |
| Fertility Effects | No known adverse effects on human fertility. Animal studies indicate no impairment of fertility at therapeutic doses. Transient use unlikely to impact reproductive function. |