Drug Guide

Generic Name

Lactulose

Brand Names Cephulac, Chronulac, Constulose, Constilac, Cholac, Enulose, Generlac, Duphalac, Portalac, Evalose, Heptalac, Acilac, Laxilose

Classification

Therapeutic: Laxative/Ammonia reducer

Pharmacological: Osmotic laxative, Disaccharide

FDA Approved Indications

Chronic constipation
Hepatic encephalopathy

Mechanism of Action

Lactulose works as an osmotic laxative by drawing water into the bowel lumen, increasing bowel movements. It is also metabolized by colonic bacteria into acids that lower colonic pH, reducing the absorption of ammonia, thus helping in hepatic encephalopathy.

Dosage and Administration

Adult: Typically 15-30 g (about 1-2 level tablespoons) taken orally 1-3 times daily, titrated to achieve 2-3 soft stools per day.

Pediatric: Dosing varies based on age; generally, 1-3 mL/kg/day divided into 1-3 doses, adjusting for effect.

Geriatric: Use with caution; start at lower doses due to possible electrolyte imbalance and dehydration risks.

Renal Impairment: Dose adjustment generally not required, but monitor electrolytes.

Hepatic Impairment: Dosing primarily targets hepatic encephalopathy; use as prescribed for hepatic encephalopathy.

Pharmacokinetics

Absorption: Minimal; mostly metabolized by colonic bacteria.

Distribution: Limited, localized in the gastrointestinal tract.

Metabolism: Metabolized by colonic bacteria into short-chain fatty acids.

Excretion: Excreted in feces.

Half Life: Depends on bowel transit time, generally 24-48 hours.

Contraindications

Galactosemia
Obstructive bowel disease
Intestinal obstruction

Precautions

Electrolyte imbalance (especially in elderly or ill patients)
Dehydration risk in the elderly, children, or severely ill

Adverse Reactions - Common

Bloating, cramping, flatulence (Common)

Adverse Reactions - Serious

Electrolyte imbalance (hypokalemia, hyponatremia, hypomagnesemia) (Rare but serious)
Dehydration (Rare)

Drug-Drug Interactions

Metformin (may increase risk of lactic acidosis, check renal function)

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Monitor bowel movements, electrolyte levels, hydration status.

Diagnoses:

Risk for electrolyte imbalance
Impaired renal function due to dehydration

Implementation: Administer as prescribed, monitor stool frequency and consistency, check electrolytes and hydration status.

Evaluation: Goal: Regular, soft bowel movements without electrolyte disturbances.

Patient/Family Teaching

Take medication with plenty of water.
Report severe cramps, bloating, or irregular heartbeat.
Maintain hydration and electrolyte balance.

Special Considerations

Black Box Warnings: N/A

Genetic Factors: None specified

Lab Test Interference: May affect blood glucose measurements; caution in diabetic patients.

Overdose Management

Signs/Symptoms: Severe diarrhea, dehydration, electrolyte imbalance.

Treatment: Discontinue medication, correct electrolytes, rehydrate as needed.

Storage and Handling

Storage: Store at room temperature, away from moisture and heat.

Stability: Stable when stored properly.