What is the recommended dose of Glycolax (polyethylene glycol 3350) for a 3-year-old child with moderate constipation?

Glycolax (Polyethylene Glycol 3350) Dosing for a 3-Year-Old

For a 3-year-old child with moderate constipation, start with 0.4 g/kg per day of polyethylene glycol 3350 mixed in 4-8 ounces of liquid, which typically translates to approximately 5-7 grams daily for an average-sized 3-year-old (12-18 kg). 1

Evidence-Based Starting Dose

• The optimal starting dose of 0.4 g/kg per day is supported by the highest quality pediatric trial, which demonstrated 74% treatment success (≥3 bowel movements per week) compared to 42% with placebo 1
• This dose provides the best balance of efficacy and tolerability, with significantly improved stool consistency (p < 0.001) and reduced straining (p < 0.05) 1
• The 0.4 g/kg dose had fewer side effects than higher doses (0.8 g/kg caused more abdominal pain and fecal incontinence) 1

Dose Titration Strategy

• Adjust the dose every 3 days based on response, with the goal of achieving 1-2 soft, non-forced bowel movements daily 2
• The effective maintenance dose typically ranges from 0.26 to 1.42 g/kg per day, with a mean of 0.78-0.84 g/kg per day across multiple studies 3, 2
• If no bowel movement occurs after 3-4 days, add a bisacodyl suppository (10 mg) or glycerin suppository while continuing PEG 4

Administration Guidelines

• Mix the powder in at least 4-8 ounces of liquid (water, juice, coffee, or tea) 4
• Juices containing sorbitol provide synergistic osmotic effects 4
• Insufficient liquid volume is a common cause of treatment failure 4
• Ensure adequate daily fluid intake beyond just the mixing liquid, as PEG requires water to work osmotically 4

Expected Timeline and Monitoring

• Stool frequency should increase significantly within the first 1-2 weeks of treatment 2
• Continue maintenance dosing once bowel movements normalize rather than stopping abruptly 4
• Treatment can be safely continued for 6+ months with sustained efficacy 2, 5

Safety Profile in Young Children

• PEG 3350 is safe and effective in children as young as 0-18 months at a mean dose of 0.78 g/kg per day 3
• Common side effects include transient diarrhea (which resolves with dose adjustment), abdominal distension, flatulence, and nausea 3, 1
• Rule out fecal impaction before starting therapy, which may require manual disimpaction or enema first 4
• Contraindicated in bowel obstruction or paralytic ileus 4

Common Clinical Pitfalls to Avoid

• Not using adequate liquid volume significantly reduces efficacy 4
• Assuming treatment failure without first optimizing dose and confirming compliance 4
• Starting with too high a dose (0.8 g/kg) increases side effects without improving efficacy 1
• Delaying rectal intervention beyond 3-4 days without a bowel movement increases risk of impaction 4

Adjunctive Measures

• Address any underlying constipation with dietary modifications (increased fluids, fiber if adequate fluid intake) 6
• Encourage regular toileting habits, especially after meals 6
• For persistent constipation despite optimal PEG dosing, consider adding oral stimulant laxative (senna or bisacodyl) 4