Management of GLP‑1 Receptor Agonist–Induced Constipation

First‑Line Pharmacologic Therapy

Polyethylene glycol 3350 (PEG 3350) 17 g mixed in 8 oz of liquid once daily is the recommended initial treatment for constipation caused by GLP‑1 receptor agonists, based on strong evidence from the 2023 AGA‑ACG chronic constipation guidelines 1.

PEG 3350 increases complete spontaneous bowel movements by ≈2.9 per week and overall spontaneous bowel movements by ≈2.3 per week compared with no treatment, demonstrating moderate‑to‑strong efficacy 2.
The therapeutic response to PEG 3350 is durable for at least 6 months of continuous use, supporting long‑term management 1.
Common adverse effects are mild and include abdominal distension, loose stools, flatulence, and nausea 1.

Psyllium fiber supplementation (taken with 8–10 oz of fluid) can be added for patients with mild symptoms or those with low dietary fiber intake, either before escalating to PEG or in combination with PEG (strong guideline recommendation) [1][2].
Fiber supplementation is low‑risk, low‑cost, and readily accessible, making it appropriate for patients whose diets are deficient in fiber 2.
The principal side effect of fiber is flatulence; wheat bran in finely ground powder form should be avoided because it may paradoxically harden stool 2.

Patients in the lowest quartile of daily fluid consumption are at higher risk for constipation; increasing fluid intake in this subgroup improves bowel regularity (strong guideline recommendation) 1.
Standard fiber supplement doses should be taken with 8–10 oz of fluid to maximize efficacy 1.

Continue PEG 3350 therapy for a minimum of 6 months, as efficacy has been shown to persist over this period 1.