Comparative Pharmacology
Head-to-head clinical analysis: CONSTILAC versus SUTAB.
Peer-Reviewed Evidence
Head-to-head clinical analysis: CONSTILAC versus SUTAB.
CONSTILAC vs SUTAB
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Constilac (lactulose) is a synthetic disaccharide that is not absorbed in the small intestine. In the colon, it is metabolized by bacteria to short-chain fatty acids (e.g., lactic acid), which osmotically draw water into the bowel, producing a laxative effect. Additionally, in hepatic encephalopathy, the acidification of colonic contents traps ammonia (NH3) as ammonium (NH4+), reducing its 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.
Oral, 15-45 mL (10-20 g lactulose) once daily, titrated to produce 2-3 soft stools daily; may be given as a single dose or divided twice daily. Onset of action 24-48 hours.
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
Not applicable due to negligible systemic absorption; lactulose acts locally in the colon.
Terminal elimination half-life: 6-8 hours in adults with normal renal function; prolonged to 20-40 hours in end-stage renal disease.
Primarily fecal as unchanged drug (systemic absorption negligible). Renal excretion accounts for <2% of any absorbed fraction. Biliary excretion is minimal.
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