Daily Polyethylene Glycol (PEG) Therapy for Chronic Idiopathic Constipation

Guideline Recommendation

The 2023 AGA‑ACG clinical practice guideline gives a strong recommendation (moderate‑certainty evidence) for daily PEG 3350 in adults with chronic idiopathic constipation (CIC). 1

In randomized controlled trials, PEG increased complete spontaneous bowel movements (CSBMs) by ≈ 2.9 per week compared with placebo (95 % CI 2.12–3.68). Population: adults with CIC; Intervention: PEG 3350 17 g daily; Control: placebo. Evidence strength: moderate. 2, 4
PEG also raised spontaneous bowel movements (SBMs) by ≈ 2.3 per week versus placebo (95 % CI 1.55–3.06). Population: adults with CIC; Intervention: PEG 3350 17 g daily; Control: placebo. Evidence strength: moderate. 2, 5

Clinical response to PEG is durable for at least 6 months, supporting its use as a long‑term daily therapy. Population: adults with CIC; Intervention: continuous daily PEG; Outcome: sustained symptom improvement. Evidence strength: strong (guideline). 1, 4

The standard regimen is 17 g PEG 3350 dissolved in ≈ 8 oz of liquid, taken once daily. Population: adults with CIC; Intervention: standard dose. Evidence strength: moderate. 3, 4
Initiation should begin with the standard 17 g daily dose. 1, 4
PEG may be prescribed alone or combined with fiber supplementation (e.g., psyllium). 1, 6
For mild constipation, a trial of fiber (particularly psyllium) can be offered before or together with PEG. 1, 6
Dose adjustments are permissible based on clinical response, although most trials used the fixed 17 g dose. 2, 3

Common, mild‑to‑moderate adverse events reported with daily PEG include abdominal distension, loose stools/diarrhea, flatulence, and nausea. Population: adults with CIC on chronic PEG; Outcome: side‑effect frequency. Evidence strength: moderate. 1, 3, 4
No serious adverse events were attributed to PEG in controlled trials. Population: adults with CIC; Intervention: PEG 3350; Outcome: safety. Evidence strength: moderate. 2, 4

PEG is reasonable as an early‑line therapy for CIC, either after a fiber trial or in combination with fiber. Population: adults with CIC; Intervention: PEG ± fiber. Evidence strength: moderate. 3, 7
Although FDA‑approved only for “occasional constipation,” PEG has demonstrated efficacy in CIC for up to 6 months in randomized trials. Population: adults with CIC; Outcome: efficacy duration. Evidence strength: moderate. 3, 7
PEG is widely available over‑the‑counter and inexpensive, facilitating broad use. 3, 7
If patients fail or cannot tolerate PEG, second‑line options include lactulose, magnesium oxide, or prescription agents. Population: adults with CIC non‑responsive to PEG. Evidence strength: moderate. 1

Evidence supports continuous daily PEG use for at least 6 months with strong supporting data. Population: adults with CIC; Intervention: daily PEG; Outcome: sustained efficacy and safety. Evidence strength: strong. 2, 4
The guideline notes that the response remains durable over 6 months, and there is no requirement for periodic drug holidays. 1, 4