VISICOL
Clinical safety rating: caution
Comprehensive clinical and safety monograph for VISICOL (VISICOL).
VISICOL (sodium phosphate) is a saline laxative that induces osmotic diarrhea, increasing water retention in the intestinal lumen, stimulating peristalsis, and promoting bowel evacuation.
| Metabolism | Metabolized through intracellular hydrolysis in the intestinal mucosa; phosphate is absorbed into systemic circulation and excreted renally. |
| Excretion | Renal: <1% (unchanged). Biliary/Fecal: >99% (as polyethylene glycol 3350, unchanged). |
| Half-life | Polyethylene glycol 3350: 4–6 hours (terminal half-life); clinically not absorbed significantly. |
| Protein binding | <1% bound (polyethylene glycol is non-charged and not protein-bound); binding proteins: negligible. |
| Volume of Distribution | Polyethylene glycol 3350: 0.01–0.02 L/kg (confined to gastrointestinal lumen; minimal systemic distribution). |
| Bioavailability | Oral: <0.2% (polyethylene glycol 3350 is minimally absorbed; systemic absorption negligible). |
| Onset of Action | Oral: 30–60 minutes to first bowel movement (colon cleansing effect). |
| Duration of Action | Duration of bowel cleansing: 3–5 hours after last dose; effects may persist for up to 24 hours. |
For bowel cleansing prior to colonoscopy: 4 tablets orally every 15 minutes with 8 oz of clear liquid until all tablets are consumed (total 32 tablets).
| Dosage form | TABLET |
| Renal impairment | Contraindicated in patients with GFR < 60 mL/min/1.73 m² due to risk of phosphate nephropathy. No dose adjustment recommended for mild impairment (GFR ≥ 60). |
| Liver impairment | No specific Child-Pugh based adjustments recommended. Use caution in severe hepatic impairment due to potential electrolyte disturbances. |
| Pediatric use | Not recommended for patients < 18 years of age due to risk of electrolyte imbalance and phosphate toxicity. |
| Geriatric use | Use with caution in elderly patients; consider monitoring renal function and electrolytes. No specific dose adjustment, but ensure adequate hydration. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for VISICOL (VISICOL).
| Breastfeeding | No data on excretion in human milk. M/P ratio unknown. Due to potential for severe electrolyte disturbances in the infant (e.g., hyperphosphatemia, hypocalcemia), use while breastfeeding is not recommended. Alternative agents are preferable. |
| Teratogenic Risk | Visicol (sodium phosphate monobasic monohydrate, sodium phosphate dibasic anhydrous) is an oral bowel evacuant. No adequate and well-controlled studies in pregnant women. Animal reproduction studies have not been conducted. There is a potential for electrolyte disturbances, particularly hyperphosphatemia and hypocalcemia, which could affect maternal and fetal homeostasis. First trimester: limited data; theoretical risk of electrolyte imbalance. Second trimester: same as first. Third trimester: increased risk of maternal hypovolemia and electrolyte shifts; consider use only if clearly needed and with careful monitoring. |
■ FDA Black Box Warning
Warning: Risk of acute phosphate nephropathy, acute renal failure, and electrolyte abnormalities. Use with caution in patients with renal impairment, bowel obstruction, or those taking medications affecting renal function.
| Serious Effects |
["Bowel obstruction or ileus","Gastric retention","Gastrointestinal perforation","Toxic colitis or megacolon","Hypersensitivity to sodium phosphate","Renal failure (creatinine clearance <50 mL/min)","Pre-existing electrolyte abnormalities (e.g., hyperphosphatemia, hypocalcemia, hypernatremia)","Congestive heart failure","Ascites"]
| Precautions | ["Acute phosphate nephropathy","Electrolyte disturbances (hyperphosphatemia, hypocalcemia, hypernatremia)","Dehydration and hypotension","Cardiac arrhythmias due to QT prolongation","Seizures","Colonic mucosal ulceration","Gastrointestinal obstruction or perforation","Renal impairment","Use with caution in elderly, debilitated patients, or those with electrolyte imbalances"] |
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| Fetal Monitoring | Monitor serum electrolytes (sodium, potassium, chloride, bicarbonate, calcium, phosphate, magnesium) before, during, and after administration. Assess volume status and renal function. Fetal monitoring for signs of distress if used near term. Evaluate for symptoms of hypocalcemia (tetany, prolonged QT interval) and hyperphosphatemia. |
| Fertility Effects | No human data on fertility effects. Animal studies have not been conducted. The drug's mechanism (osmotic laxative) is unlikely to directly affect fertility, but severe electrolyte disturbances could theoretically impair reproductive function. No evidence of impaired fertility in reproductive-aged patients. |