Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
CEPHULAC vs CLENPIQ
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
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.
Picosulfate is hydrolyzed by colonic bacteria to the active metabolite bis-(p-hydroxyphenyl)-pyridyl-2-methane (BHPM), which stimulates colonic peristalsis and promotes fluid and electrolyte accumulation in the colon. Magnesium oxide and citric acid generate magnesium citrate, an osmotic agent that draws water into the colon. Combined effects induce bowel cleansing.
Treatment of constipation,Hepatic encephalopathy (portal-systemic encephalopathy) including the prevention and treatment of coma
Cleansing of the colon as a preparation for colonoscopy in adults
30-45 m L (6.67-10 g lactulose) orally 3-4 times daily for constipation; for hepatic encephalopathy, 30-45 m L orally 3-4 times daily titrated to produce 2-3 soft stools per day, or 300 m L in 700 m L of water or saline as retention enema for 30-60 min every 4-6 hours.
Two separate doses: first dose (5 mg prucalopride + 10 mg bisacodyl) orally, followed by a second dose (5 mg prucalopride + 10 mg bisacodyl) orally 6-12 hours later. Total dose: 10 mg prucalopride + 20 mg bisacodyl.
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.
Sodium picosulfate: terminal half-life 7.4 hours (clinically not relevant as action is colonic); magnesium oxide and citric acid produce bicarbonate; half-life not applicable for osmotic component
Not absorbed; metabolized by colonic bacteria (e.g., Lactobacillus, Bacteroides) to low molecular weight organic acids.
Bisacodyl (picosulfate) is hydrolyzed by colonic bacteria to its active metabolite BHPM; magnesium citrate acts locally.
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 fecal (97–98%) as unchanged drug; negligible renal excretion (<2%)
Negligible (<5%): lactulose does not bind significantly to albumin or other plasma proteins due to its hydrophilic nature.
Sodium picosulfate: <5% bound to plasma proteins
0.5-1.0 L/kg (estimated from systemic absorption studies; limited data due to minimal absorption; reflects distribution largely into extracellular water).
Sodium picosulfate: Vd ~0.2 L/kg (confined mainly to extracellular fluid, low tissue penetration)
Oral: <3% (due to poor absorption and extensive metabolism by colonic bacteria; most of the drug remains in the gut lumen). Rectal: similar to oral, as systemic absorption is minimal.
Oral (sodium picosulfate): low systemic bioavailability (<10%) due to extensive first-pass activation in colon; magnesium citrate is a locally active osmotic agent with negligible systemic absorption
No dose adjustment required for renal impairment as lactulose is minimally absorbed and primarily acts locally in the colon.
Contraindicated if e GFR < 30 m L/min/1.73 m². For e GFR 30-59 m L/min/m²: reduce total prucalopride dose to 5 mg (i.e., single administration only).
Not specifically adjusted based on Child-Pugh score; dose is titrated to achieve desired stool frequency; caution in severe hepatic impairment due to risk of electrolyte disturbances.
Contraindicated in severe hepatic impairment (Child-Pugh class C). No dose adjustment required for mild to moderate impairment (Child-Pugh A or B).
Infants: 2.5-10 m L/day in divided doses; older children: 10-25 m L/day; adolescents: 15-30 m L/day; all for constipation; for hepatic encephalopathy, doses as low as 5-10 m L 3-4 times daily with dose adjusted to produce 2-3 soft stools per day.
Not approved for use in pediatric patients (<18 years). Safety and efficacy not established.
Initiate at lower end of dosing range (15-30 m L/day) due to increased risk of dehydration and electrolyte imbalance; monitor for diarrhea and adjust accordingly.
No specific dose adjustment required solely based on age. Consider renal function (e GFR) and overall frailty; use conservative dosing in elderly with renal impairment (see renal_adjustment).
None
WARNING: RISK OF SERIOUS FLUID AND ELECTROLYTE ABNORMALITIES. CLENPIQ can cause significant fluid and electrolyte shifts, which may lead to serious adverse events including cardiac arrhythmias, seizures, and renal impairment. Monitor and correct electrolytes before use in patients at risk.
Electrolyte imbalance with prolonged use, especially in debilitated patients,Diarrhea may cause fluid and electrolyte loss,Galactose intolerance (contraindicated in patients requiring low galactose diet due to lactose content in some preparations),Monitor serum electrolytes in patients receiving high doses for hepatic encephalopathy
Risk of fluid and electrolyte abnormalities,Cardiac arrhythmias due to electrolyte imbalance,Seizures associated with electrolyte abnormalities,Renal impairment,Mucosal ulceration,Use with caution in patients with impaired gag reflex, reflux, or aspiration risk,Colonic mucosal aphthous ulcerations
Patients requiring a low-galactose diet (lactulose contains galactose and lactose),Intestinal obstruction,Suspected gastrointestinal obstruction or perforation
Gastrointestinal obstruction,Gastric retention,Bowel perforation,Toxic colitis,Toxic megacolon,Ileus,Hypersensitivity to any component,Severe renal impairment (e GFR <30 m L/min/1.73m²)
No specific food interactions. Avoid concurrent use with other laxatives unless directed. High-fiber foods may enhance effect; ensure adequate fluid intake.
Avoid solid food during bowel preparation. Only clear liquids (water, clear broth, black coffee/tea, clear fruit juices without pulp, gelatin, popsicles) are permitted. Do not consume milk, cream, or any dairy products. Avoid red or purple colored liquids that may be mistaken for blood during colonoscopy. Do not consume alcohol.
Lactulose (CEPHULAC) is not absorbed systemically; therefore, fetal exposure is negligible. Animal studies have not shown teratogenic effects. In clinical practice, no fetal risks have been identified in any trimester.
No adequate and well-controlled studies in pregnant women. In animal reproduction studies, oral administration of picosulfate sodium plus magnesium oxide (components of CLENPIQ) to pregnant rats during organogenesis at doses up to 1.2 times the human dose (based on body surface area) did not produce fetal harm. However, because animal studies are not always predictive of human response, CLENPIQ should be used during pregnancy only if clearly needed. During the first trimester, consider alternative bowel preparation to avoid any theoretical risk. In second and third trimesters, use only if potential benefit justifies potential risk to fetus.
Lactulose is not excreted into breast milk due to minimal systemic absorption. It is considered compatible with breastfeeding. M/P ratio: Not applicable (negligible absorption).
Excretion in human milk unknown. M/P ratio not available. Because many drugs are excreted in human milk, caution should be exercised when CLENPIQ is administered to a nursing woman. Consider temporary discontinuation of breastfeeding during the 24-hour period after CLENPIQ administration.
No dose adjustment required. Pharmacokinetics are unchanged in pregnancy due to lack of systemic absorption. Standard dosing of 15-30 m L (10-20 g) once daily, up to 60 m L/day in divided doses, is appropriate.
No dose adjustment recommendations available due to lack of pharmacokinetic studies in pregnancy. However, physiological changes in pregnancy (increased plasma volume, renal blood flow) may affect drug disposition; use lowest effective dose and ensure adequate hydration. No specific dose reduction recommended.
Cephulac (lactulose) is a non-absorbable disaccharide used for constipation and hepatic encephalopathy. In hepatic encephalopathy, titrate to produce 2-3 soft stools per day. Monitor serum electrolytes, especially in elderly or renal impairment. Onset of action for constipation may be 24-48 hours. Do not confuse with other lactose-containing products.
CLENPIQ (sodium picosulfate, magnesium oxide, and citric acid) is a colonoscopy preparation. Ensure adequate hydration before, during, and after use. Common adverse effects include nausea, vomiting, and abdominal distension. Contraindicated in patients with severe renal impairment (Cr Cl <30 m L/min), gastrointestinal obstruction, ileus, or known hypersensitivity. Avoid use within 1 hour of antacids or medications that affect gastrointestinal motility.
Take exactly as prescribed; may take 24-48 hours to produce a bowel movement.,For hepatic encephalopathy, maintain 2-3 soft stools daily; do not skip doses.,May cause bloating, gas, or cramping initially; usually resolves.,Do not take other laxatives without consulting your doctor.,Report severe diarrhea, vomiting, or muscle cramps to your healthcare provider.
Take CLENPIQ as a split-dose regimen: one bottle the evening before and one bottle the morning of the colonoscopy.,Do not take any other laxatives or bowel preparations concurrently.,Stay hydrated by drinking clear liquids before and after each dose.,Do not eat solid food during the preparation period; only clear liquids are allowed.,Common side effects include nausea, bloating, and abdominal cramps; contact your doctor if severe or persistent.,Avoid driving or operating machinery if you feel dizzy or lightheaded.,Inform your doctor of all medications, especially diuretics, ACE inhibitors, ARBs, NSAIDs, or any drugs affecting kidney function.
No interactions on record
No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about CEPHULAC vs CLENPIQ, answered by our medical review team.
CEPHULAC is a Laxative that works by 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.. CLENPIQ is a Laxative that works by Picosulfate is hydrolyzed by colonic bacteria to the active metabolite bis-(p-hydroxyphenyl)-pyridyl-2-methane (BHPM), which stimulates colonic peristalsis and promotes fluid and electrolyte accumulation in the colon. Magnesium oxide and citric acid generate magnesium citrate, an osmotic agent that draws water into the colon. Combined effects induce bowel cleansing.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between CEPHULAC and CLENPIQ depend on the specific clinical indication. These are both Laxative agents and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of CEPHULAC is: 30-45 m L (6.67-10 g lactulose) orally 3-4 times daily for constipation; for hepatic encephalopathy, 30-45 m L orally 3-4 times daily titrated to produce 2-3 soft stools per day, or 300 m L in 700 m L of water or saline as retention enema for 30-60 min every 4-6 hours.. The standard adult dose of CLENPIQ is: Two separate doses: first dose (5 mg prucalopride + 10 mg bisacodyl) orally, followed by a second dose (5 mg prucalopride + 10 mg bisacodyl) orally 6-12 hours later. Total dose: 10 mg prucalopride + 20 mg bisacodyl.. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
No direct drug-drug interaction has been formally documented between CEPHULAC and CLENPIQ in current clinical databases. However, individual patient risk factors including other medications, organ function, and comorbidities should always be evaluated by a qualified healthcare provider.
The maternal-fetal safety profiles differ. CEPHULAC is classified as Category C. Lactulose (CEPHULAC) is not absorbed systemically; therefore, fetal exposure is negligible. Animal studies have not shown teratogenic effects. In clinical practice, no fetal risks . CLENPIQ is classified as Category C. No adequate and well-controlled studies in pregnant women. In animal reproduction studies, oral administration of picosulfate sodium plus magnesium oxide (components of CLENPIQ) to. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.