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

Microlax, an osmotic laxative administered rectally, is employed to manage several clinical situations that require rapid bowel evacuation or preparation of the distal colon.

• Occasional constipation: provides rapid softening of stool, increases water content in the colon, and facilitates complete evacuation within minutes.
• Pre‑procedure bowel preparation: effectively clears the rectum and distal colon, reducing fecal residue before diagnostic imaging, endoscopic evaluation, or minor surgical procedures.
• Fecal impaction relief: assists in softening and expelling impacted stool in patients with limited mobility or neurologic disorders, when oral laxatives are insufficient.
• Colonoscopy preparation: ensures thorough rectal clearance, improving visualization and reducing the risk of contamination during colonoscopic procedures.

• Microlax works by creating an osmotic gradient in the colon. Sodium citrate and sorbitol draw water into the lumen, increasing stool liquidity. Sodium lauryl sulfoacetate acts as a surfactant, stimulating the rectal mucosa and promoting peristaltic activity, which together result in rapid bowel evacuation. The increased intraluminal fluid softens the fecal mass, while the mild irritation of the mucosa enhances motility, leading to evacuation within 5–15 minutes after administration.

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

Common Side Effects

• Mild rectal irritation: transient burning or stinging sensation.
• Cramping: brief abdominal or rectal cramps.
• Loose stools: watery bowel movements shortly after use.
• Nausea: occasional feeling of nausea.

Serious or Rare Side Effects

• Severe abdominal pain: persistent intense pain requiring medical attention.
• Allergic reaction: rash, swelling, or difficulty breathing.
• Electrolyte imbalance: rare disturbance due to excessive fluid loss.

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

• Contraindication: avoid in patients with known hypersensitivity to any component.
• Caution in bowel obstruction: do not use if mechanical obstruction is suspected.
• Use in children: limit to age‑appropriate dosing as directed by a healthcare professional.
• Fluid loss: monitor for dehydration if used repeatedly.
• Pregnancy and lactation: consult a physician before use during pregnancy or breastfeeding.
• Store at ambient temperature: keep below 25 °C, in the original container, protected from moisture and direct sunlight.

Microlax can interact with certain medications or conditions; awareness of these interactions helps prevent reduced efficacy or adverse events.

Major Interactions (Avoid)

• Antidiarrheal agents: may counteract the laxative effect.
• Oral electrolyte supplements: risk of electrolyte imbalance when combined with excessive use.

Moderate Interactions (Monitor Closely)

• Lithium therapy: increased lithium reabsorption due to altered fluid balance.
• Digoxin: potential for altered serum levels if significant fluid shifts occur.
• Other osmotic laxatives: additive effect may cause excessive fluid loss.