Section 19 · Monograph
Polyethylene glycol 3350
Reviewed Nov 2026FDA label
MiraLAXOsmotic laxative
- Forms
- Powder: 17g per dose
- Dose
- Constipation: 17g in 120-240mL fluid once daily, titrate
- MOA
- Retains water in the stool through osmosis
Indications
- Occasional constipation (OTC); prescription use for chronic constipationFDA-labeled
Mechanism of Action
- Nonabsorbed osmotic agent that retains water in the stool, softening it and increasing frequency
Full Dosing
Adult / usual
- 17g (one heaping tablespoon) dissolved in 120-240mL fluid once daily; titrate to a soft daily stool
- Can be combined with a stimulant laxative for opioid-induced or neurogenic constipation
- Effect in 1-3 days
Contraindications
- Known or suspected bowel obstruction
- Hypersensitivity to polyethylene glycol
Drug Interactions
- No significant drug interactions
- May alter absorption of drugs given close to bowel preparation doses
Adverse Effects
- Bloating, flatulence, nausea
- Loose stools or diarrhea
- Rarely, allergic reactions
Monitoring Parameters
- Stool frequency and consistency
- Hydration if diarrhea occurs
Pregnancy & Lactation
- Minimal systemic absorption; considered acceptable
- Compatible with breastfeeding