Comparative Pharmacology
Head-to-head clinical analysis: PORTALAC versus SUTAB.
Peer-Reviewed Evidence
Head-to-head clinical analysis: PORTALAC versus SUTAB.
PORTALAC vs SUTAB
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
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.
SUTAB is a combination tablet consisting of sodium sulfate, magnesium sulfate, and potassium chloride. It acts as an osmotic laxative by drawing water into the bowel lumen through the osmotic effect of sulfate ions, inducing colonic evacuation. Additionally, magnesium ions enhance this effect by attracting water via osmotic pressure and stimulating the release of cholecystokinin, which promotes peristalsis.
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.
24 tablets administered as 4 tablets every 15 minutes, total dose of 17.5 g sodium sulfate, 3.13 g magnesium sulfate, and 1.64 g potassium sulfate, orally, with water, the evening before colonoscopy.
None Documented
None Documented
1.7-2.0 hours (terminal); clinical context: short t1/2 allows rapid dose adjustment in hepatic encephalopathy.
Terminal elimination half-life: 6-8 hours in adults with normal renal function; prolonged to 20-40 hours in end-stage renal disease.
Renal: ~40% as unchanged drug; fecal: ~60% as metabolites (biliary excretion of conjugates and lactulose).
Primarily renal excretion (65-75% unchanged) with minor biliary/fecal elimination (<10%). Total body clearance approximates renal blood flow.
Category C
Category C
Osmotic Laxative
Osmotic Laxative