Recommended Dosage and Treatment Duration for Miralax (Polyethylene Glycol) for Constipation
For adults with constipation, the recommended dose of Miralax (polyethylene glycol 3350) is 17 grams once daily mixed in 4-8 ounces of beverage, with treatment duration of up to 6 months for chronic idiopathic constipation. 1, 2
Dosing Recommendations
- The standard recommended dose for adults and children 17 years and older is 17 grams of polyethylene glycol (PEG) 3350 once daily 2
- The powder should be fully dissolved in 4-8 ounces of any beverage (cold, hot, or room temperature) before drinking 2
- For short-term constipation relief, PEG can be used for up to 7 days without physician supervision 2
- For chronic idiopathic constipation (CIC), treatment has been shown to be effective and durable for up to 6 months 1
- Children 16 years of age or under should only use PEG under physician guidance 2
Efficacy and Response Timeline
- Most patients experience a bowel movement within 24 hours of taking the first dose 3
- In clinical studies, the average time to first bowel movement was approximately 14.8 hours with a therapeutic dose 3
- PEG significantly increases the number of complete spontaneous bowel movements (CSBMs) per week compared to placebo (mean difference 2.90, CI 2.12-3.68) 1
- Response to PEG treatment has been shown to be durable over a 6-month period 1
- For chronic constipation, approximately 83.3% of patients achieve normalization of bowel movements after 14 days of treatment 4
Special Considerations for Chronic Use
- Long-term studies have demonstrated that PEG remains safe and effective for treating constipation for periods up to 12 months, with no evidence of tachyphylaxis (decreased response over time) 5
- For patients with medication-induced constipation, PEG has shown a 78.3% success rate compared to 39.1% with placebo 6
- PEG is particularly effective for elderly patients with constipation, with 84-94% reporting successful treatment 5
- For mild constipation, a trial of fiber supplement can be considered before PEG use or in combination with PEG 1
Potential Side Effects
- Common side effects include abdominal distension, loose stool, flatulence, and nausea 1
- Diarrhea may occur more commonly in the treatment group but is generally mild to moderate in severity 1, 5
- No significant changes in laboratory findings, including electrolytes, have been observed even with long-term use 6, 5
Important Precautions
- Do not combine PEG with starch-based thickeners used for difficult swallowing 2
- Ensure the powder is fully dissolved before drinking; do not drink if there are any clumps 2
- For short-term use without medical supervision, do not use for more than 7 consecutive days 2
- If constipation persists beyond 7 days of treatment, consult a healthcare provider 2
- After discontinuation of treatment, approximately 61.7% of patients may require additional constipation treatment interventions within 30 days 4