• Chronic constipation.
• Adjunct in the management of portal-systemic (hepatic) encephalopathy.

Contraindicated in:

• Patients on low-galactose diets.

Use Cautiously in:

• Diabetes mellitus
• Excessive or prolonged use (may lead to dependence)
• Lactation: Safety not established in breastfeeding.

Endo: hyperglycemia (patients with diabetes).

GI: belching, cramps, distention, flatulence, diarrhea.

Drug-Drug:

• Should not be used with other laxatives in the treatment of hepatic encephalopathy (leads to inability to determine optimal dose of lactulose).
• Anti-infectives may ↓ effectiveness in treatment of hepatic encephalopathy.

(Generic available)

• Oral solution: 10 g/15 mL;
• Single-use packets (Kristalose): 10 g (equal to 15 mL liquid lactulose); 20 g (equal to 30 mL liquid lactulose);

Constipation

• PO (Adults): 15–30 mL/day up to 60 mL/day as liquid or 10–20 g as powder for oral solution (up to 40 g/day has been used).
• PO (Children): 7.5 mL once daily after breakfast (unlabeled).

Portal-Systemic Encephalopathy

• PO (Adults): 30–45 mL 3–4 times/day; may be given every 1–2 hr initially to induce laxation.
• PO (Infants): 2.5–10 mL/day in 3–4 divided doses (unlabeled).
• PO (Children and Adolescents): 40–90 mL/day in 3–4 divided doses (unlabeled).
• Rect (Adults): 300 mL diluted and administered as a retention enema every 4–6 hr.

Constulose, Enulose, Generlac, Kristalose

• Increases water content and softens the stool.
• Lowers the pH of the colon, which inhibits the diffusion of ammonia from the colon into the blood, thereby reducing blood ammonia levels.

• Relief of constipation.
• Decreased blood ammonia levels with improved mental status in portal-systemic encephalopathy.

Therapeutic Classification: laxatives

Pharmacologic Classification: osmotics

Absorption: Less than 3% absorbed after oral administration.

Distribution: Unknown.

Metabolism/Excretion: Absorbed lactulose is excreted unchanged in the urine. Unabsorbed lactulose is metabolized by colonic bacteria to lactic, acetic, and formic acids.

Half-life: Unknown.

(relief of constipation)

• Explain purpose of lactulose to patient. Instruct patient to take lactulose as directed.
• Encourage patients to use other forms of bowel regulation, such as increasing bulk in the diet, increasing fluid intake, and increasing mobility. Normal bowel habits are individualized and may vary from 3 times/day to 3 times/wk.
• Caution patients that this medication may cause belching, flatulence, or abdominal cramping. Health care professional should be notified if this becomes bothersome or if diarrhea occurs.
• Advise females of reproductive potential to notify health care professional if pregnancy is planned or suspected or if breastfeeding.

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