CHOLAC
Clinical safety rating
cautionComprehensive clinical and safety monograph for CHOLAC (CHOLAC).
Lactulose is a synthetic disaccharide that is not absorbed in the small intestine. It is metabolized by colonic bacteria to short-chain fatty acids, primarily lactic acid and acetic acid, which lower the colonic pH. This acidification traps ammonia (NH3) as ammonium (NH4+) in the gut lumen, reducing serum ammonia levels. Additionally, the osmotic effect of lactulose draws water into the colon, producing a laxative effect.
| Metabolism | Not absorbed systemically. Metabolized by colonic bacteria (e.g., Lactobacillus, Bacteroides) to lactic acid, acetic acid, and other short-chain fatty acids. |
| Excretion | Primarily fecal (biliary excretion of unchanged drug and metabolites); minimal renal excretion (<5%). |
| Half-life | 0.5-1.5 hours for lactulose; active metabolites (e.g., acetic acid) have negligible systemic half-life due to rapid local metabolism. |
| Protein binding | Negligible (<1%); not significantly bound to plasma proteins. |
| Volume of Distribution | Approximately 0.2 L/kg; indicates distribution primarily in extracellular fluid. |
| Bioavailability | Oral: <2% systemic bioavailability due to extensive first-pass metabolism and local gut action; rectal: minimal systemic absorption. |
| Onset of Action | Oral: 24-48 hours for laxative effect; 30 minutes to 2 hours for ammonia reduction via rectal administration. |
| Duration of Action | Laxative effect persists 24-48 hours after single dose; ammonia-lowering effect sustained during therapy. |
| Molecular Weight | 342.3 |
15-30 mL (10-20 g lactulose) orally once daily, titrated to produce 2-3 soft stools per day; maximum dose 60 mL/day. For hepatic encephalopathy: 30-45 mL (20-30 g) orally 3-4 times daily, titrated to 2-3 soft stools per day.
| Dosage form | SOLUTION |
| Renal impairment | No dose adjustment required for renal impairment. |
| Liver impairment | No specific Child-Pugh based adjustments. Use with caution in severe hepatic impairment due to risk of electrolyte disturbances; monitor serum electrolytes. |
| Pediatric use | Infants: 2.5-10 mL/day in divided doses. Children: 40-90 mg/kg/day (as lactulose) divided 1-2 times daily, titrated to produce soft stools. For hepatic encephalopathy: 2.5-10 mL (1.7-6.7 g) orally 3-4 times daily, titrated to 2-3 soft stools per day. |
| Geriatric use | Initiate at lower end of dosing range (15 mL once daily) and titrate slowly to avoid diarrhea and electrolyte imbalance; monitor renal function and electrolytes. |
| 1st trimester | Limited human data; no evidence of fetal harm from animal studies. Use only if clearly needed. |
| 2nd trimester | No known teratogenic risk; monitor for maternal electrolyte imbalance. |
| 3rd trimester | No reported adverse fetal effects; use caution in pregnant women with bowel obstruction. |
Clinical note
Comprehensive clinical and safety monograph for CHOLAC (CHOLAC).
| Placental transfer | Minimal due to poor systemic absorption; expected to cross placenta only in negligible amounts. |
| Breastfeeding | Cholac (lactulose) is minimally absorbed systemically; concentrations in breast milk are likely negligible. It is considered compatible with breastfeeding. |
| Lactation Rating | L1 (Safe) |
| Teratogenic Risk | Lactulose is not absorbed systemically; no teratogenic effects reported in animal studies or human case reports. FDA Pregnancy Category B. Trimester-specific risks: no known fetal harm in any trimester. |
| Fetal Monitoring | Monitor maternal electrolyte levels (especially potassium, chloride) with prolonged use due to potential diarrhea-induced losses. Fetal monitoring not required. |
| Fertility Effects | No known effects on fertility in animal or human studies. |
■ FDA Black Box Warning
No FDA black box warning.
| Serious Effects |
GalactosemiaBowel obstructionIntestinal perforationAcute surgical abdomen
| Precautions | Electrolyte disturbances (e.g., hypernatremia) may occur, especially with prolonged use or in patients with renal impairment, Diarrhea can lead to fluid and electrolyte loss; dosage should be adjusted to produce 2-3 soft stools per day, Galactose content: lactulose contains galactose and lactose; use with caution in patients with galactose intolerance, Lapp lactase deficiency, or glucose-galactose malabsorption, Risk of colonic perforation in patients with severe colonic ulceration, toxic megacolon, or gastrointestinal obstruction |
| Food/Dietary | No specific food restrictions. Mixing with fruit juice, water, or milk may improve taste. Avoid excessive intake of dairy products if lactose intolerant (lactulose may contain small amounts of lactose). |
| Clinical Pearls | Cholac (lactulose) is used for constipation and hepatic encephalopathy. Monitor for diarrhea and electrolyte imbalances. In hepatic encephalopathy, titrate dose to achieve 2-3 soft stools per day. Syrup can be mixed with fruit juice or water to improve palatability. Onset of action is 24-48 hours for constipation; for encephalopathy, effects may take several days. |
| Patient Advice | Take exactly as prescribed. Do not change dose without consulting your doctor. · For constipation, effects may take up to 48 hours. Do not use other laxatives unless advised. · For liver disease, it helps reduce ammonia levels. Aim for 2-3 soft bowel movements daily. · May cause gas, bloating, or stomach cramps, which usually decrease over time. · Contact doctor if you have severe diarrhea, vomiting, or signs of dehydration. · Store at room temperature, away from heat and direct light. |
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