Comparative Pharmacology
Head-to-head clinical analysis: GOLYTELY versus PORTALAC.
Peer-Reviewed Evidence
Head-to-head clinical analysis: GOLYTELY versus PORTALAC.
GOLYTELY vs PORTALAC
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Polyethylene glycol 3350 is an osmotic laxative that induces diarrhea by retaining water in the bowel lumen through osmotic activity. Electrolytes (sodium sulfate, potassium chloride, sodium bicarbonate) prevent significant electrolyte absorption or loss.
Lactulose is a synthetic disaccharide that is not absorbed from the gastrointestinal tract. It is metabolized by colonic bacteria to short-chain fatty acids (e.g., acetic, lactic, and formic acid), resulting in acidification of colonic contents and an increase in osmotic pressure, which stimulates bowel evacuation. In hepatic encephalopathy, acidification reduces blood ammonia levels by converting NH3 to NH4+ in the colon, inhibiting ammonia absorption.
240 mL (oral) every 10 minutes until 4 L consumed or rectal effluent is clear; typically 4 L total over 3-4 hours.
Initial: 15-30 mL (10-20 g lactulose) orally, 2-3 times daily; titrate to 2-3 soft stools daily. For acute hepatic encephalopathy: 30-45 mL (20-30 g) orally every hour until evacuation, then 3-4 times daily.
None Documented
None Documented
Not applicable (PEG 3350 is not significantly absorbed; effective half-life in GI tract is approximately 2-4 hours for colonic clearance).
1.7-2.0 hours (terminal); clinical context: short t1/2 allows rapid dose adjustment in hepatic encephalopathy.
Primarily fecal elimination of unabsorbed polyethylene glycol 3350. Minimal systemic absorption (<0.06%), less than 0.06% recovered in urine as intact PEG 3350; electrocytes and sulfate (from sodium sulfate) are renally excreted.
Renal: ~40% as unchanged drug; fecal: ~60% as metabolites (biliary excretion of conjugates and lactulose).
Category C
Category C
Osmotic Laxative
Osmotic Laxative