Comparative Pharmacology
Head-to-head clinical analysis: NULYTELY versus PORTALAC.
Peer-Reviewed Evidence
Head-to-head clinical analysis: NULYTELY versus PORTALAC.
NULYTELY vs PORTALAC
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Polyethylene glycol (PEG) 3350 is an osmotic agent that induces diarrhea by drawing water into the gastrointestinal tract, thereby cleansing the bowel. Sodium sulfate and electrolytes (sodium, potassium, bicarbonate) are added to prevent fluid and electrolyte shifts.
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.
4 liters orally of the reconstituted solution as a single dose for colonoscopy preparation, typically administered in divided doses (e.g., 240 mL every 10 minutes) until rectal effluent is clear. Alternatively, a split-dose regimen: half the solution evening before, half on the day of procedure.
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; NULYTELY is not systemically absorbed in significant amounts, so a terminal elimination half-life is not defined. The drug acts locally in the gastrointestinal tract.
1.7-2.0 hours (terminal); clinical context: short t1/2 allows rapid dose adjustment in hepatic encephalopathy.
NULYTELY (polyethylene glycol 3350) is minimally absorbed systemically (<0.06%). The primary route of elimination is fecal excretion of the intact polymer. Renal excretion is negligible (<0.02%).
Renal: ~40% as unchanged drug; fecal: ~60% as metabolites (biliary excretion of conjugates and lactulose).
Category C
Category C
Osmotic Laxative
Osmotic Laxative