Uses
Portal-Systemic Encephalopathy
Used as an adjunct to protein restriction and supportive therapy for prevention and treatment of portal-systemic encephalopathy (PSE), including hepatic pre-coma and coma.
Useful in the management of PSE resulting from surgical portacaval shunts or chronic hepatic diseases such as cirrhosis.
Reduces blood ammonia concentration, which usually leads to substantial improvement in patient’s mental state and EEG tracings.
Does not alter the course of underlying liver disease and therefore does not obviate treatment of such disease or PSE.
Since neomycin destroys bacteria and lactulose requires bacterial degradation for its effectiveness, concomitant therapy with these agents is theoretically counterproductive. (See Anti-infective Agents under Interactions.) However, some evidence suggests that concomitant therapy with lactulose and neomycin may be more effective than either drug alone.
Not useful in the management of non-nitrogenous types of encephalopathy such as those induced by drugs or metabolic or electrolyte disturbances. Not effective in the treatment of coma associated with infectious hepatitis or other acute liver disorders.
Chronic Constipation
Useful as a laxative in the treatment of chronic constipation in adults, including geriatric patients. Superiority compared with conventional laxatives not established.
Used in the treatment of chronic constipation in children†; safety and efficacy in children not established.
Used to restore regular bowel movements following hemorrhoidectomy†.
Used to induce bowel evacuation in geriatric patients with colonic retention of barium and severe constipation following barium meal examination†.
Dosage and Administration
Administration
Administer orally, via gastric tube, or rectally.
Oral Administration
When solution is administered orally, may minimize sweet taste by diluting with water, fruit juice, milk or by adding to food (e.g., desserts).
When administering via gastric tube, dilute well to prevent induction of vomiting and possible aspiration pneumonia.
Reconstitution
For oral administration, reconstitute powder by dissolving contents of a 10- or 20-g packet in approximately 120 mL of water.
Rectal Administration
May administer rectally to adults with PSE during stages of hepatic pre-coma or coma when the possibility of aspiration exists or when necessary endoscopic or intubation procedures interfere with oral administration.
Reconstitution
For rectal administration, dilute 200 g of powder in 700 mL of water or 0.9% sodium chloride solution and administer via a rectal balloon catheter.
Dosage
Each 15 mL of commercially available lactulose solution provides approximately 10 g of the drug; corresponding doses provided by 2.5, 5, 7.5, 10, 30, 40, 45, 90, 150, and 300 mL of the commercial solution are approximately 1.67, 3.3, 5, 6.67, 20, 27, 30, 60, 100, and 200 g, respectively. Following reconstitution of the oral powder as directed, a 10- or 20-g dose is provided by administering the total volume.
Pediatric Patients
Portal-Systemic Encephalopathy
Oral
Infants (limited data): Initially, 1.67–6.67 g daily in divided doses.
Older children and adolescents: Initially, 27–60 g daily recommended by manufacturer.
Adjust dosage every 1–2 days as necessary to produce 2–3 soft stools daily.
If the initial dose produces diarrhea, reduce dose immediately; if diarrhea persists, discontinue drug.
Chronic Constipation
At least 5 g daily, usually given as a single dose after breakfast, has been used.
Adults
Portal-Systemic Encephalopathy
Oral
20–30 g 3 or 4 times daily.
Adjust dosage every 1–2 days as necessary to produce 2 or 3 soft stools daily. Usually dosage is 60–100 g daily; some patients may require higher dosage.
Some clinicians recommend dosage adjustment according to acidity of colonic contents by measuring stool pH (with indicator paper) at initiation of therapy and adjusting dosage until stool pH is about 5. This pH is usually achieved when the patient has 2 or 3 soft stools daily during therapy.
In the management of acute PSE episodes, give 20–30 g orally at 1- to 2-hour intervals to induce rapid laxation. When the laxative effect has been achieved, reduce dosage to the amount required to produce 2 or 3 soft stools daily.
During treatment, improvement in patient’s clinical condition usually occurs within 1–3 days.
Continuous long-term therapy with lactulose may decrease severity and prevent recurrence of PSE.
Rectal
For reversal of hepatic coma, 200 g is diluted with 700 mL of water or 0.9% sodium chloride solution and administered rectally via a rectal balloon catheter; solution is retained for 30–60 minutes.
Retention enemas may be administered every 4–6 hours. If enema retained for <30 minutes, may repeat administration immediately.
In some patients, reversal of hepatic coma may occur within 2 hours of the first enema. Before discontinuance of lactulose retention enemas, initiate recommended oral dosages of the drug.
Chronic Constipation
Oral
Usual initial dosage is 10–20 g daily. Dosage may be increased to 40 g daily if necessary.
Following oral administration, 24–48 hours may be required to restore normal bowel movements.
To facilitate bowel movements in patients undergoing hemorrhoidectomy†, administer 10 g twice daily on the day before surgery and twice daily for 5 days postoperatively.
To induce bowel evacuation in geriatric patients with colonic retention of barium and severe constipation following barium meal examination†, 3.3–6.7 g twice daily for 1–4 weeks has been administered.
Special Populations
Dosage in Hepatic Impairment
Hepatic Impairment
Oral
No specific dosage recommendations for patients with hepatic impairment.
Dosage in Renal Impairment
Renal Impairment
Oral
No specific dosage recommendations for patients with renal impairment.
Geriatric Patients
No specific dosage recommendations for geriatric patients.
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