Comparative Pharmacology
Head-to-head clinical analysis: CEPHULAC versus HEPTALAC.
Peer-Reviewed Evidence
Head-to-head clinical analysis: CEPHULAC versus HEPTALAC.
CEPHULAC vs HEPTALAC
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Lactulose, a synthetic disaccharide, is not absorbed from the gastrointestinal tract. It is metabolized by colonic bacteria to form short-chain fatty acids (e.g., lactic, acetic, formic acids), which acidify the colonic contents. In hepatic encephalopathy, the acidic environment converts ammonia (NH3) to ammonium (NH4+), which is poorly absorbed and excreted in feces. Additionally, the osmotic effect of lactulose draws water into the colon, softening stools and increasing bowel movements.
Ammonia scavenger; lactulose is metabolized by colonic bacteria to organic acids, acidifying the colon, which converts NH3 to NH4+ and promotes ammonia excretion. Lactulose also reduces colonic transit time and bacterial production of ammonia.
30-45 mL (6.67-10 g lactulose) orally 3-4 times daily for constipation; for hepatic encephalopathy, 30-45 mL orally 3-4 times daily titrated to produce 2-3 soft stools per day, or 300 mL in 700 mL of water or saline as retention enema for 30-60 min every 4-6 hours.
Oral: 3.33 g (30 mL) 3 times daily. Rectal: 200 mL of 30% solution as retention enema, 3 times daily. Intravenous: 30 g as a single dose via intra-abdominal instillation.
None Documented
None Documented
Terminal elimination half-life is 7-10 hours (renal impairment: prolonged); systemic absorption is minimal (<3%) after oral administration, so half-life reflects clearance of absorbed fraction.
Terminal elimination half-life is 6-12 hours in patients with normal hepatic function; prolonged in hepatic encephalopathy due to altered clearance (up to 24 hours).
Primarily renal (20-30% as unchanged drug) and fecal (up to 70% as unmetabolized drug via biliary elimination; following gastric acid-mediated degradation, only 5-10% reaches urine as intact lactulose; hepatic metabolism is negligible).
Primarily renal (approximately 70-80%) as unchanged drug; minor biliary/fecal elimination (20-30%).
Category C
Category C
Laxative
Laxative