Comparative Pharmacology
Head-to-head clinical analysis: CONSTILAC versus GLYCOLAX.
Peer-Reviewed Evidence
Head-to-head clinical analysis: CONSTILAC versus GLYCOLAX.
CONSTILAC vs GLYCOLAX
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.
Osmotic laxative. Polyethylene glycol (PEG) increases intraluminal water volume in the colon by osmosis, promoting stool passage and relieving constipation.
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.
17 g (1 heaping tablespoon) dissolved in 4-8 ounces of liquid once daily, orally.
None Documented
None Documented
Not applicable due to negligible systemic absorption; lactulose acts locally in the colon.
Not applicable due to negligible systemic absorption; local colonic transit time approximately 2-4 hours.
Primarily fecal as unchanged drug (systemic absorption negligible). Renal excretion accounts for <2% of any absorbed fraction. Biliary excretion is minimal.
Minimally absorbed; excreted primarily unchanged in feces via osmotic action. Renal excretion negligible (<0.2% absorbed dose).
Category C
Category C
Osmotic Laxative
Osmotic Laxative