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. |
| Molecular Weight | 138.0 Da (sodium phosphate monohydrate); 141.96 Da (dibasic anhydrous) |
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 | Not recommended due to limited data and potential for mechanical bowel obstruction; use only if clearly needed. |
| 2nd trimester | Use with caution; may be used if benefit outweighs risk as bowel preparation for procedures. |
| 3rd trimester | Avoid near term due to risk of fluid and electrolyte imbalance, which may affect fetal well-being. |
Clinical note
Comprehensive clinical and safety monograph for VISICOL (VISICOL).
| Placental transfer | No data on placental transfer; however, sodium phosphate salts are small molecules and theoretical transfer may occur. Avoid use during pregnancy unless necessary. |
| Breastfeeding | Visicol (sodium phosphate monobasic monohydrate and sodium phosphate dibasic anhydrous) is not absorbed systemically in significant amounts; excretion into breast milk is unlikely. However, due to lack of data, use with caution and consider alternative bowel preparations. |
■ 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 |
Gastrointestinal obstructionGastric retentionBowel perforationToxic colitisMegacolonKnown hypersensitivity to sodium phosphate salts
| 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 |
| Food/Dietary | Avoid alcohol, dairy products, and solid foods during the bowel preparation. Only consume clear liquids such as water, clear broth, apple juice, black coffee or tea without milk, and gelatin desserts. Avoid red, purple, or orange liquids that may interfere with colonoscopy visualization. |
Loading safety data…
| Lactation Rating | L3 - Moderately Safe |
| 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. |
| 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. |
| Clinical Pearls | VISICOL (sodium phosphate monobasic monohydrate, sodium phosphate dibasic anhydrous) is an oral colonic lavage solution used for bowel cleansing prior to colonoscopy. It can cause acute phosphate nephropathy, especially in patients with renal impairment, those taking ACE inhibitors, ARBs, diuretics, or NSAIDs, and in elderly patients. Ensure adequate hydration. Do not use in patients with pre-existing electrolyte abnormalities, ascites, or bowel obstruction. Monitor renal function and electrolytes post-procedure. |
| Patient Advice | Take VISICOL as a split-dose regimen: one dose the evening before and the second dose the morning of the colonoscopy, following your doctor's instructions exactly. · Drink plenty of clear liquids before, during, and after taking this medication to prevent dehydration and kidney injury. · Avoid taking other laxatives or stool softeners while using VISICOL. · Inform your doctor if you have kidney disease, heart problems, electrolyte disorders, or are taking blood pressure medications. · Common side effects include nausea, vomiting, bloating, and abdominal discomfort. Contact your doctor if you experience severe pain, vomiting, or signs of dehydration. |