lactulose

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.

Adv. Reactions/Side Effects ⬆ ⬇

Endo: hyperglycemia (patients with diabetes)

GI: belching, cramps, distention, flatulence, diarrhea

Interactions ⬆ ⬇

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.

Availability ⬆ ⬇

(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)

Route/Dosage ⬆ ⬇

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 ): 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.

US Brand Names ⬆ ⬇

Constulose, Enulose, Generlac, Kristalose

Action ⬆ ⬇

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.

Therapeutic effects:

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

Classifications ⬆ ⬇

Therapeutic Classification: laxatives

Pharmacologic Classification: osmotics

Pharmacokinetics ⬆ ⬇

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.

Time/Action Profile ⬆ ⬇

(relief of constipation)

ROUTE	ONSET	PEAK	DURATION
PO	24–48 hr	unknown	unknown

Patient/Family Teaching ⬆ ⬇

Explain purpose and side effects of lactulose to patient. Instruct patient to take lactulose as directed. May mix drug with fruit juice, water, or milk. If patient is using drug to relieve constipation, inform patient that drug effects may not be seen for 24–48 hr. Advise patient to read Patient Information before starting and with each Rx refill in case of changes.
Encourage patients to use other forms of bowel regulation, such as ↑ bulk in the diet, fluid intake, and 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 provider should be notified if this becomes bothersome or if diarrhea occurs.
Advise patient to notify health care provider of all Rx or OTC medications, vitamins, or herbal products being taken and to consult with health care provider before taking other medications. Use with other laxatives is not recommended.
Rep: Advise women of reproductive potential to notify health care provider if pregnancy is planned or suspected or if breastfeeding.

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Indications ⬇

Contraind./Precautions ⬆ ⬇