HEPTALAC
Clinical safety rating: caution
Comprehensive clinical and safety monograph for HEPTALAC (HEPTALAC).
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.
| Metabolism | Not absorbed; metabolized in the colon by bacterial enzymes (e.g., lactulose is hydrolyzed by β-galactosidase to lactic acid and small amounts of acetic acid). |
| Excretion | Primarily renal (approximately 70-80%) as unchanged drug; minor biliary/fecal elimination (20-30%). |
| Half-life | 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). |
| Protein binding | <10% bound to plasma proteins; albumin and globulins. |
| Volume of Distribution | 0.3-0.6 L/kg; distributes mainly in extracellular fluid and minimal tissue penetration. |
| Bioavailability | Oral: approximately 30-50% (first-pass metabolism in colon); Rectal: variable, approximately 20-40%. |
| Onset of Action | Oral: 8-12 hours for clinical improvement in encephalopathy; Rectal: 4-6 hours; Intravenous: not applicable (no IV formulation). |
| Duration of Action | Duration of therapeutic effect: 12-24 hours; clinical improvement sustained with continued dosing. Note: Acidification of colon pH reduces ammonia absorption. |
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.
| Dosage form | SOLUTION |
| Renal impairment | No dose adjustment required for renal impairment. Lactulose is minimally absorbed and acts primarily in the colon. |
| Liver impairment | No dose adjustment required for hepatic impairment. Lactulose is used specifically in hepatic encephalopathy (Child-Pugh Class C), but dose titration based on response (2-3 soft stools per day). |
| Pediatric use | Infants: 2.5-10 mL/day in divided doses. Children: 40-90 mL/day in divided doses. Adolescents: Adult dosing. Titrate to produce 2-3 soft stools per day. |
| Geriatric use | No specific dose adjustment. Initiate at low end of adult dosing and titrate to desired bowel movement frequency. Caution in patients with electrolyte imbalances. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for HEPTALAC (HEPTALAC).
| Breastfeeding | Excreted in breast milk in low amounts; M/P ratio unknown. Consider risk-benefit. |
| Teratogenic Risk | Insufficient human data; animal studies show no teratogenicity at therapeutic doses. Avoid first trimester unless benefit outweighs risk. |
| Fetal Monitoring | Monitor liver function, ammonia levels, and neurological status. Fetal ultrasound if used in pregnancy. |
■ FDA Black Box Warning
No FDA black box warning.
| Serious Effects |
["Patients with galactosemia (lactulose contains galactose)","Intestinal obstruction (relative contraindication due to risk of exacerbation)","Hypersensitivity to lactulose or any component"]
| Precautions | ["Monitor for electrolyte disturbances (hypokalemia, hypernatremia) in prolonged use.","Risk of diarrhea and ensuing fluid/electrolyte loss.","Use with caution in patients with galactose intolerance (lactulose contains galactose and lactose).","May cause abdominal discomfort, flatulence, and nausea."] |
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| Fertility Effects | No known effects on fertility in animal studies; human data lacking. |