LAXILOSE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for LAXILOSE (LAXILOSE).
Laxilose (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, acetic, formic acids), which osmotically draw water into the bowel lumen, stimulating peristalsis and softening stools. Additionally, in hepatic encephalopathy, colonic acidification traps ammonia (NH3) as ammonium (NH4+), reducing systemic ammonia absorption.
| Metabolism | Metabolized by colonic bacteria (e.g., Bifidobacterium, Lactobacillus) to organic acids; minimal systemic absorption. |
| Excretion | Primarily renal excretion, with approximately 40% of the dose recovered as unchanged drug in urine; biliary/fecal excretion accounts for the remainder, including metabolites. |
| Half-life | Terminal elimination half-life is 2.5-4 hours in patients with normal renal function; prolonged to up to 20 hours in severe renal impairment. |
| Protein binding | Approximately 30% bound to plasma proteins, primarily albumin. |
| Volume of Distribution | 0.3-0.6 L/kg, indicating distribution mainly in extracellular fluid. |
| Bioavailability | Oral bioavailability is 70-85% due to first-pass metabolism. |
| Onset of Action | Oral: 1-2 hours; Intravenous: 5-15 minutes. |
| Duration of Action | Oral: 8-12 hours; Intravenous: 4-6 hours; duration may be increased in renal impairment. |
10-20 g (15-30 mL) orally once daily; may increase to 40 g (60 mL) daily in divided doses.
| Dosage form | SOLUTION |
| Renal impairment | No dosage adjustment required for renal impairment. |
| Liver impairment | No specific guidelines; use with caution in severe hepatic encephalopathy due to risk of electrolyte disturbances. |
| Pediatric use | Children 1-5 years: 2.5-5 g (3.75-7.5 mL) once daily; children 6-12 years: 5-10 g (7.5-15 mL) once daily. |
| Geriatric use | Initiate at lower end of dosing range (10 g or 15 mL daily) due to increased risk of dehydration and electrolyte imbalance; titrate based on response. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for LAXILOSE (LAXILOSE).
| Breastfeeding | Lactulose is minimally absorbed and excretion into breast milk is negligible; M/P ratio is not determined due to lack of systemic absorption. It is considered compatible with breastfeeding. No adverse effects on the nursing infant have been reported. |
| Teratogenic Risk | Lactulose (Laxilose) is not absorbed systemically following oral administration, thus it does not reach fetal circulation. Studies indicate no increased risk of major malformations or other adverse pregnancy outcomes. However, data are limited to small observational studies and post-marketing reports. Based on mechanism and minimal systemic absorption, it is considered low risk for teratogenicity in all trimesters. Use during pregnancy is generally acceptable when dietary measures fail. |
■ FDA Black Box Warning
None
| Common Effects | Abdominal pain Nausea Vomiting Diarrhea |
| Serious Effects |
["Patients with galactosemia (cannot metabolize galactose)","Known hypersensitivity to lactulose or any component of the formulation","Patients with gastrointestinal obstruction or perforation","Emergency surgery for gastrointestinal obstruction"]
| Precautions | ["Diarrhea may cause electrolyte disturbances (e.g., hypokalemia, hypernatremia) and fluid loss, especially with prolonged use.","Use with caution in patients with galactose intolerance (lactulose contains lactose and galactose).","May cause abdominal discomfort, flatulence, and bloating initially.","Monitor for signs of excessive diarrhea or dehydration.","Not recommended for acute abdominal pain or suspected bowel obstruction without medical evaluation."] |
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| Fetal Monitoring | No specific maternal or fetal monitoring is required beyond routine prenatal care. Monitor for excessive flatulence, abdominal distension, or electrolyte disturbances if used long-term in high doses, especially in patients with renal impairment. |
| Fertility Effects | No studies have investigated effects of lactulose on human fertility. Based on its pharmacokinetic profile (minimal systemic absorption), it is unlikely to impact fertility. |