CITRIC ACID; MAGNESIUM OXIDE; SODIUM PICOSULFATE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for CITRIC ACID; MAGNESIUM OXIDE; SODIUM PICOSULFATE (CITRIC ACID; MAGNESIUM OXIDE; SODIUM PICOSULFATE).
Sodium picosulfate is a stimulant laxative that is hydrolyzed by colonic bacteria to the active metabolite bis-(p-hydroxyphenyl)-pyridyl-2-methane, which stimulates colonic peristalsis by acting on the colonic mucosa and inhibiting water and electrolyte absorption. Magnesium oxide acts as an osmotic laxative by drawing water into the intestinal lumen. Citric acid reacts with magnesium oxide to form magnesium citrate, an osmotic laxative.
| Metabolism | Sodium picosulfate is hydrolyzed by colonic bacteria to its active metabolite. Magnesium and citrate are not metabolized; they are absorbed and excreted renally. |
| Excretion | Sodium picosulfate is primarily excreted in feces (90-95%) as the active metabolite BHPM via biliary elimination; <5% excreted renally. Magnesium oxide is excreted renally as magnesium ions. Citric acid is metabolized to bicarbonate and excreted renally. |
| Half-life | The terminal elimination half-life of the active metabolite BHPM is approximately 7-9 hours; clinical effect (bowel cleansing) begins within 1-3 hours and is complete by 6 hours. |
| Protein binding | Sodium picosulfate and its active metabolite BHPM are minimally protein bound (<5%); magnesium oxide and citric acid are not significantly protein bound. |
| Volume of Distribution | The volume of distribution of the active metabolite BHPM is not well defined; magnesium distributes mainly to extracellular fluid (0.2-0.4 L/kg). |
| Bioavailability | Sodium picosulfate is a prodrug; systemic bioavailability of BHPM after oral administration is approximately 10-15% due to extensive presystemic metabolism. |
| Onset of Action | Oral administration: onset of bowel evacuation occurs within 1-3 hours. |
| Duration of Action | Duration of bowel cleansing effect is typically 3-6 hours post-dose; complete evacuation usually occurs within 6-8 hours. |
Adult: 10 mg oral sodium picosulfate (as 10 mg powder for oral solution) plus 3.5 g magnesium oxide and 12 g citric acid, taken as a single dose the day before colonoscopy, followed by a second dose the next morning, for a total of 2 doses.
| Dosage form | FOR SOLUTION |
| Renal impairment | Contraindicated in patients with severe renal impairment (eGFR < 30 mL/min/1.73 m²). For eGFR 30-60, use with caution and ensure adequate hydration. |
| Liver impairment | No specific adjustment provided; use with caution in severe hepatic impairment (Child-Pugh C) due to potential for electrolyte disturbances. |
| Pediatric use | Safety and efficacy not established in pediatric patients; not recommended for use in children. |
| Geriatric use | No specific dose adjustment; ensure adequate hydration and monitor electrolyte levels due to increased risk of renal impairment and dehydration. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for CITRIC ACID; MAGNESIUM OXIDE; SODIUM PICOSULFATE (CITRIC ACID; MAGNESIUM OXIDE; SODIUM PICOSULFATE).
| Breastfeeding | Unknown if components excreted in human milk. Sodium picosulfate may be excreted in small amounts; magnesium and citrate are normal milk constituents. Risk to infant considered low with single doses, but caution advised with chronic use. M/P ratio not available. |
| Teratogenic Risk | No adequate studies in pregnant women. In animal studies, sodium picosulfate showed no teratogenic effects at clinically relevant doses. Theoretical risk of electrolyte disturbances from magnesium absorption may affect fetal development; avoid in first trimester if possible. Insufficient data for second and third trimesters; use only if clearly needed. |
■ FDA Black Box Warning
Risk of acute phosphate nephropathy and renal failure, particularly in patients at increased risk (e.g., renal impairment, dehydration, medications affecting renal function).
| Serious Effects |
["Gastrointestinal obstruction, ileus, or perforation","Renal failure (creatinine clearance < 30 mL/min)","Ascites","Congestive heart failure (NYHA class III or IV)","Known hypersensitivity to any component"]
| Precautions | ["Do not use in patients with gastrointestinal obstruction, perforation, or ileus.","Use caution in patients with renal impairment, electrolyte abnormalities, or those taking medications that affect electrolyte balance.","Monitor for fluid and electrolyte disturbances.","Avoid use in patients with known hypersensitivity to any component."] |
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| Fetal Monitoring | Monitor maternal serum electrolytes (magnesium, sodium, potassium) and renal function during prolonged use. Assess for signs of dehydration, especially in pregnant patients. Fetal heart rate monitoring not specifically required. |
| Fertility Effects | No known effects on fertility. Magnesium oxide and citric acid are not expected to impair fertility; sodium picosulfate has no reported fertility impact in animal studies. |