Comparative Pharmacology
Head-to-head clinical analysis: CONSTILAC versus NULYTELY FLAVORED.
Peer-Reviewed Evidence
Head-to-head clinical analysis: CONSTILAC versus NULYTELY FLAVORED.
CONSTILAC vs NULYTELY-FLAVORED
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.
NULYTELY-FLAVORED is an osmotic laxative containing polyethylene glycol (PEG) 3350 and electrolytes. It induces diarrhea by retaining water in the colon through osmotic action, thereby cleansing the bowel.
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.
Adult dose: 4 liters of reconstituted solution orally as a single dose, or 240 mL (8 oz) every 10 minutes until 4 liters are consumed, approximately 1-1.5 hours before colonoscopy.
None Documented
None Documented
Not applicable due to negligible systemic absorption; lactulose acts locally in the colon.
Not applicable; PEG 3350 is not significantly absorbed and does not exhibit a terminal elimination half-life in the systemic circulation. Clinical effect is due to local osmotic action in the gut.
Primarily fecal as unchanged drug (systemic absorption negligible). Renal excretion accounts for <2% of any absorbed fraction. Biliary excretion is minimal.
Primarily fecal elimination as unabsorbed PEG 3350; minimal systemic absorption (<0.06%). Renal excretion of absorbed fraction is negligible.
Category C
Category C
Osmotic Laxative
Osmotic Laxative