Volume 152, Issue 4, Pages 675-680 (March 2017) Seventy Years of Polyethylene Glycols in Gastroenterology: The Journey of PEG 4000 and 3350 From Nonabsorbable Marker to Colonoscopy Preparation to Osmotic Laxative  John S. Fordtran  Gastroenterology  Volume 152, Issue 4, Pages 675-680 (March 2017) DOI: 10.1053/j.gastro.2017.01.027 Copyright © 2017 AGA Institute Terms and Conditions

Figure 1 A, Sodium concentrations in fluid aspirated from the stomach and small intestine of normal subjects after they consumed a natural meal. In about one-half of the studies, 10 g of polyethylene glycol (PEG) 4000 was dissolved in the liquid portion of the meal. The sodium concentration increased rapidly in the duodenum and jejunum to approximately 140 mEq/L, but in the ileum sodium concentration varied widely between 97 and 156 mEq/L. B, When PEG was not present in the test meal, sodium concentration in ileal fluid was similar to plasma, averaging 140 mEq/L (range, 133-157). When the meal contained 10 g of PEG, there was an inverse correlation between sodium and PEG concentrations in the aspirated ileal fluid. Gastroenterology 2017 152, 675-680DOI: (10.1053/j.gastro.2017.01.027) Copyright © 2017 AGA Institute Terms and Conditions

Figure 2 Contrasting effects of plasmalike electrolyte and NaKSO4-polyethylene glycol (PEG) solutions on fluid absorption and colonic irrigation volume under steady-state conditions. The solutions were infused into the stomach at a rate of 30 mL/min. Over a 3-hour period, 5400 mL of solution was infused. After a steady state had been established, rectal effluent was collected for 3 hours as the intragastric infusion was continued. See text for a discussion of the results. Gastroenterology 2017 152, 675-680DOI: (10.1053/j.gastro.2017.01.027) Copyright © 2017 AGA Institute Terms and Conditions

Figure 3 Laxative effects of polyethylene glycol (PEG) 3350. Normal subjects ingested 53, 95, 190, or 252 g/d of PEG 3350 each day during 4-day experimental periods while they consumed their regular diet. These amounts were ingested in 4 divided doses, with each main meal and at bedtime. (A) Effect on stool weight and fecal fluid PEG concentration. When no PEG 3350 was ingested, stool weight averaged 146 g/d. Increasing doses of PEG 3350 were associated with a corresponding increase in daily stool weight. PEG concentration in stool was almost as high when PEG intake was 53 g/d as when PEG intake was 252 g/d. (B) Percent water content of stools during ingestion of various laxatives. Diarrheal stools produced by PEG 3350 had lower percent water concentrations (and higher percent solid concentrations) than diarrheal stools produced by other laxatives under similar experimental conditions: lactulose (▪), milk of magnesia (Δ), phenolphthalein (▼), and sodium sulfate (○). Gastroenterology 2017 152, 675-680DOI: (10.1053/j.gastro.2017.01.027) Copyright © 2017 AGA Institute Terms and Conditions