Microlax (Sodium Citrate, Sorbitol (E420), Sodium Lauryl Sulfoacetate)

• Microlax is an osmotic rectal laxative used to treat conditions affecting bowel motility and stool consistency.
• Occasional constipation: provides rapid softening of stool and facilitates evacuation without systemic absorption.
• Bowel cleansing before diagnostic or therapeutic procedures: clears the rectum to improve visualization and preparation for examinations such as colonoscopy or surgery.
• Pre‑operative bowel preparation: ensures an empty rectum to reduce infection risk during surgery.
• Diagnostic imaging preparation: improves image quality for barium enema or other rectal studies.
• Rapid onset of action: typically produces a bowel movement within 5–20 minutes.

• Microlax works by combining osmotic agents and a surfactant. Sodium citrate and sorbitol create an osmotic gradient that draws water into the intestinal lumen, increasing stool fluidity. Sodium lauryl sulfoacetate reduces surface tension of the fecal mass, stimulating intestinal motility and facilitating the passage of softened stool through the rectum. The combined action results in rapid, localized bowel evacuation without significant systemic absorption.

Microlax may cause local and systemic reactions, most of which are mild and transient.

Common Side Effects

• Mild rectal irritation or burning sensation that usually resolves quickly.
• Cramping or abdominal discomfort occurring shortly after administration.
• Urgency to defecate or increased frequency of bowel movements for a short period.
• Watery or loose stool resulting from the osmotic effect.
• Transient nausea or mild feeling of queasiness that usually subsides quickly.

Serious or Rare Side Effects

• Severe abdominal pain or colic that persists beyond the initial evacuation.
• Allergic reactions such as rash, facial swelling, or difficulty breathing requiring medical attention.
• Rectal bleeding or hemorrhage, especially if the mucosa is traumatized.
• Electrolyte imbalance such as low sodium, though rare, may occur with excessive use.

Before using Microlax, consider the following precautions to ensure safe and effective use.

• Contraindicated in intestinal obstruction: avoid use if there is a known blockage of the bowel.
• Avoid in inflammatory bowel disease flare-ups: may exacerbate symptoms during active disease.
• Allergy assessment: do not use if hypersensitivity to sodium citrate, sorbitol or sodium lauryl sulfoacetate is known.
• Pregnancy and lactation: safety not established; use only if clearly needed after medical advice.
• Frequency of use: limit to occasional relief; prolonged use may cause electrolyte disturbances.
• Store at room temperature: keep container tightly closed, protect from moisture and direct sunlight.

Microlax can interact with certain medications; consider the following when co‑administering.

Major Interactions (Avoid)

• None identified: no major drug–drug interactions have been reported for the rectal enema formulation.

Moderate Interactions (Monitor Closely)

• Diuretics: concurrent use may increase risk of electrolyte imbalance due to additional fluid loss.
• Other laxatives or stool softeners: additive effect may cause excessive bowel stimulation or diarrhea.
• Antacids containing magnesium or aluminum: may alter the osmotic activity of sorbitol.
• Oral electrolyte supplements: monitor serum levels if Microlax is used frequently.
• Antibiotics that affect gut flora: may increase risk of diarrhea when combined with Microlax.
• Cardiovascular drugs that rely on fluid balance (e.g., ACE inhibitors): monitor blood pressure if large volumes are used repeatedly.