Magnesium Sulfate, Potassium Sulfate, and Sodium Sulfate

This combination of sulfate salts is an osmotic laxative oral solution used exclusively to clean out the colon before a colonoscopy.

• Approved for colonoscopy bowel prep in adult patients across all labeled oral solution products
• SUPREP Bowel Prep Kit is approved for colonoscopy prep in adults and pediatric patients 12 years of age and older
• Potassium Sulfate and Magnesium Sulfate Oral solution is approved for colonoscopy prep in adults and pediatric patients 12 years of age and older
• Several other labeled oral solution products are approved for adult use only — pediatric approval is product-specific and not universal across all formulations

This prep contains sulfate salts (sodium sulfate, potassium sulfate, and magnesium sulfate) that are poorly absorbed by the gut. Because they stay inside the intestine, they draw water inward through osmosis — the natural movement of water toward areas of higher concentration. This retained water flushes the colon clear, producing the bowel movements needed to prepare for colonoscopy.

This solution is taken by mouth using a split-dose, two-day regimen — one dose the evening before the colonoscopy and one dose the morning of the procedure. Each dose must be diluted with water before drinking, and extra water must be consumed after each dose to stay hydrated. Stop all fluids at least 2 hours before the scheduled colonoscopy. Always follow your prescriber's exact instructions and the directions in your kit — do not take both doses in a single evening, as this is not a recommended regimen and is associated with more side effects.

• Must dilute in water before ingesting — never take undiluted
• Drink additional water after each dose as directed
• Take other oral medications at least 1 hour before starting each dose
• Stop fluids at least 2 hours before colonoscopy

Most people will experience some GI discomfort — that is expected with any bowel prep. Common side effects include:

• Overall discomfort
• Abdominal bloating or distension
• Abdominal pain or cramping
• Nausea
• Vomiting

More serious reactions to watch for include signs of dehydration, irregular heartbeat, seizures, or a severe allergic reaction (trouble breathing, throat swelling, hives). Seek medical help right away if any of these occur.

• Fluid and electrolyte imbalance: The biggest risk. Losing too much water or minerals can cause serious heart rhythm problems, seizures, or kidney injury. Drink plenty of water as directed and get lab tests if your doctor recommends it.
• Cardiac arrhythmias (irregular heartbeat): Rare but serious. People with a history of prolonged QT interval, heart failure, recent heart attack, unstable angina, or cardiomyopathy should discuss the risks with their doctor before use. An ECG (heart tracing) may be recommended before and after the procedure.
• Seizures: Have been reported, mostly linked to electrolyte abnormalities. Extra caution is needed for people with a history of seizures, those withdrawing from alcohol or benzodiazepines, or those taking medications that lower the seizure threshold.
• Kidney injury: People with kidney disease or those taking diuretics, ACE inhibitors, ARBs, or NSAIDs are at higher risk. Lab testing before and after may be needed.
• Severe allergic reactions (anaphylaxis): Rare but possible. Seek emergency care immediately for breathing difficulty, facial swelling, or hives.
• Colonic ulceration or ischemic colitis (reduced blood flow to the colon): Risk increases if stimulant laxatives are used at the same time — avoid them.
• Aspiration risk: People with swallowing problems or a weak gag reflex should be monitored during administration.
• Gout flares: This prep can temporarily raise uric acid levels, which may trigger a gout attack in susceptible people.

This bowel prep can interact with several types of medications — tell your doctor and pharmacist about everything you take before using it.

• Diuretics, ACE inhibitors, ARBs, NSAIDs: Increase risk of kidney injury and electrolyte problems when combined with this prep
• Tricyclic antidepressants and other drugs that lower seizure threshold: Raise the risk of seizures if electrolytes become abnormal during prep
• Stimulant laxatives (bisacodyl, sodium picosulfate): Avoid — combining these with this prep raises the risk of colonic ulcerations and ischemic colitis
• All oral medications: Take at least 1 hour before starting each dose, as this prep can reduce drug absorption
• Tetracycline and fluoroquinolone antibiotics, iron, digoxin, chlorpromazine, penicillamine: Take at least 2 hours before and no less than 6 hours after each dose — magnesium in the prep can bind to these drugs and reduce their effectiveness
• Medications that prolong the QT interval (affect heart rhythm): Use with caution; electrolyte shifts during prep may worsen the risk

This is not a complete list of interactions. Always talk with your doctor or pharmacist before starting, stopping, or changing any medication.

• Do not use if you have a bowel blockage (obstruction or ileus), bowel perforation, gastric retention, or toxic colitis or megacolon
• Do not use if you have a known allergy to any ingredient in the solution
• Kidney disease: Use with caution; may need lab tests before and after the prep
• Heart disease or irregular heart rhythm: Discuss risks with your doctor; an ECG may be recommended
• History of seizures: Use with extra caution; inform your doctor
• Gout or uric acid disorders: Prep can temporarily raise uric acid — discuss with your doctor beforehand
• Severe active ulcerative colitis: Use with caution
• Swallowing difficulties or impaired gag reflex: Should be monitored during use due to aspiration risk
• Children under 12: Safety and effectiveness have not been established
• Older adults: More likely to be sensitive to fluid and electrolyte changes — monitor carefully
• Pregnancy: No human data available on safety — discuss with your doctor
• Breastfeeding: No data available on whether the drug passes into breast milk — discuss with your doctor

Taking more than the recommended amount of this prep can lead to severe electrolyte disturbances, dehydration, and low blood volume (hypovolemia). These can cause serious heart, kidney, and neurological problems. If an overdose is suspected, monitor for fluid and electrolyte imbalances and seek medical treatment promptly.

After taking this solution, sulfate levels in the blood peak at about 17 hours after the first dose and around 5 hours after the second dose. Sulfate then clears from the body with a half-life of about 8.5 hours — meaning the body eliminates roughly half of it every 8.5 hours. The primary route of elimination is through the stool (fecal excretion). In people with moderate kidney impairment, sulfate exposure is somewhat higher than in people with normal kidney function, but these differences are not considered clinically meaningful. Liver impairment does not appear to significantly affect how the body handles sulfate from this prep.

Store at 20°C to 25°C (68°F to 77°F). Keep out of reach of children.