Magnesium Sulfate / Potassium Sulfate / Sodium Sulfate Dosage

Medically reviewed by Drugs.com. Last updated on Jul 28, 2025.

Usual Adult Dose for Bowel Preparation

Split-Dose Regimen (Preferred Method):

• Dose 1: 1.6 grams magnesium sulfate-3.13 grams potassium sulfate-17.5 grams sodium sulfate (per 6-ounce bottle) orally ONCE in the evening before the colonoscopy, followed by 32 ounces of water orally within the next hour
• Dose 2: 1.6 grams magnesium sulfate-3.13 grams potassium sulfate-17.5 grams sodium sulfate (per 6-ounce bottle) orally ONCE the day of the colonoscopy, followed by 32 ounces of water orally within the next hour

Comments:

• Note: This drug should be diluted with 16 ounces of cool water prior to administration.
• Patients may consume a light breakfast or clear liquids on Day 1 (e.g., no solid foods).
• Dose 2 should be administered approximately 10 to 12 hours after Dose 1; dosing should be completed at least 2 hours before the colonoscopy.
• Patients should consume only clear liquids (e.g., no solid food or dairy) up until 2 hours before the time of the colonoscopy.
• Those who experience severe bloating, distention, or abdominal pain may delay the second dose until the symptoms resolve.

Use: Cleansing of the colon as a preparation for colonoscopy

Usual Pediatric Dose for Bowel Preparation

12 years and older:
Split-Dose Regimen (Preferred Method):

• Dose 1: 1.2 grams magnesium sulfate-2.35 grams potassium sulfate-13.13 grams sodium sulfate (per 4.5-ounce bottle) orally ONCE in the evening before the colonoscopy, followed by 24 ounces of water orally within the next hour
• Dose 2: 1.2 grams magnesium sulfate-2.35 grams potassium sulfate-13.13 grams sodium sulfate (per 4.5-ounce bottle) orally ONCE the day of the colonoscopy, followed by 24 ounces of water orally within the next hour

Comments:

• Note: This drug should be diluted with 12 ounces of cool water prior to administration.
• Patients may consume a light breakfast or clear liquids on Day 1 (e.g., no solid foods).
• Dose 2 should be administered approximately 10 to 12 hours after Dose 1; dosing should be completed at least 2 hours before the colonoscopy.
• Patients should consume only clear liquids (e.g., no solid food or dairy) up until 2 hours before the time of the colonoscopy.
• Those who experience severe bloating, distention, or abdominal pain may delay the second dose until the symptoms resolve.

Use: Cleansing of the colon as a preparation for colonoscopy

Renal Dose Adjustments

Renal dysfunction and/or patients taking concomitant agents that may affect renal function:
Use with caution; patients should be advised regarding adequate hydration, and baseline and pos-colonoscopy tests should be considered (e.g., blood urea nitrogen [BUN], creatinine, electrolytes).

Liver Dose Adjustments

Data not available

Precautions

CONTRAINDICATIONS:

• Hypersensitivity to any/all the active components or to any of the ingredients
• Patients with bowel perforation
• Patients with gastric retention
• Patients with gastrointestinal obstruction or ileus
• Patients with toxic colitis/megacolon

Safety and efficacy have not been established in patients younger than 12 years; this drug is not recommended for use in these patients.

Consult WARNINGS section for additional precautions.

Dialysis

Data not available

Other Comments

Administration advice:

• Once reconstituted, this drug should be consumed immediately.
• Solid food, milk, red/purple drinks, and/or alcohol should be avoided during use.
• Additional oral medications should not be taken within an hour of taking this drug; fluoroquinolone or tetracycline antibiotics, chlorpromazine, digoxin, iron, and/or penicillamine should be taken at least 2 hours before OR 6 hours after administration of this drug.
• Additional laxative use should be avoided.

Reconstitution/preparation techniques:

• Oral solutions should be diluted prior to administration; the manufacturer product information should be consulted for further details.

General:

• Limitation of use: This drug should not be used as a routine laxative.

Monitoring:

• METABOLIC: Consider baseline and post-colonoscopy electrolyte monitoring in patients with renal dysfunction
• RENAL: Consider baseline and post-colonoscopy blood urea nitrogen and creatinine level monitoring in patients with renal dysfunction

Patient advice:

• Patients should be instructed to closely follow their healthcare providers' instructions regarding bowel preparation.
• Advise patients to remain adequately hydrated while using this drug.
• Advise patients to speak to their healthcare provider if they become pregnant, intend to become pregnant, or are breastfeeding.

See also:

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer