Comparative Pharmacology
Head-to-head clinical analysis: PLENVU versus PORTALAC.
Peer-Reviewed Evidence
Head-to-head clinical analysis: PLENVU versus PORTALAC.
PLENVU vs PORTALAC
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
PLENVU is an osmotic laxative that induces bowel cleansing by causing water retention in the colon, leading to increased intraluminal pressure and stimulation of peristalsis. Its components (polyethylene glycol 3350, sodium ascorbate, ascorbic acid, sodium sulfate) act synergistically to produce a cathartic effect.
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.
2 sachets (each containing ascorbic acid 4.7g, macrogol 3350 52.5g, sodium ascorbate 5.9g, sodium sulfate 3.75g) dissolved in water to a total volume of 500mL, administered orally as a split-dose regimen: first dose (2 sachets in 500mL water) at 6-9 pm on the day before colonoscopy, followed by additional 500mL of clear fluids; second dose (2 sachets in 500mL water) on the morning of colonoscopy, completed at least 2 hours before the procedure, followed by additional 500mL of clear fluids.
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 (non-absorbed agent); systemic absorption is minimal, so no terminal half-life is defined.
1.7-2.0 hours (terminal); clinical context: short t1/2 allows rapid dose adjustment in hepatic encephalopathy.
Primarily fecal (90-95%) as unabsorbed drug; renal excretion is negligible (<1%).
Renal: ~40% as unchanged drug; fecal: ~60% as metabolites (biliary excretion of conjugates and lactulose).
Category C
Category C
Osmotic Laxative
Osmotic Laxative