lactulose (Rx)
Generic: Lactulose
Brand: Constulose, Enulose, Generlac, Kristalose
(lak'tyoo-lose)
Pharmacological Action
Prevents absorption of ammonia in colon by acidifying stool; increases water, softens stool
Therapeutic outcome: Decreased constipation, decreased blood ammonia level
Uses
Chronic constipation, portal-systemic encephalopathy in patients with hepatic disease
Contraindications
Hypersensitivity, low-galactose diet
Precautions: Pregnancy B, breastfeeding, geriatric and debilitated patient, diabetes mellitus
Dosage & Routes
Constipation
Adult: PO 15-30 ml/day (10-20 g), may increase to 60 ml/day prn Child (unlabeled): PO 7.5 ml/day Hepatic encephalopathy
Adult: PO 30-45 ml (20-30 g) tid or qid until stools are soft; retention enema 300 ml diluted
Infant: PO 2.5-10 ml/day in divided doses
Child: PO 40-90 ml/day in divided doses given 3-4×/day
Available forms: Oral sol (encephalopathy) 10 g/15 ml; oral sol (constipation) 10 g/15 ml
Implementation
PO route: - Give with full glass of fruit juice, water, milk to increase palatability of oral form; for rapid effect, give on empty stomach; increase fluids by 2 L/day; do not give with other laxatives; if diarrhea occurs, reduce dosage -
Kristalose: dissolve contents of packet in 4 oz of water
Rectal route: - Administer retention enema by diluting 300 ml of lactulose/700 ml of water or of 0.9% NaCl; administer by rect balloon catheter; retain for 30-60 min; repeat if evacuated too quickly
Adverse Effects
GI: Nausea, vomiting, anorexia, abdominal cramps, diarrhea, flatulence, distention, belching
META: Hypernatremia
Pharmacokinetics
Absorption: Poorly absorbed
Distribution: Not known
Metabolism: Colonic bacteria to acids
Excretion: Kidneys, unchanged
Half-life: Unknown
Pharmacodynamics
Unknown
Interactions
Individual drugs
Neomycin: decreased lactulose effect NIFEdipine extended release tab: increased GI obstruction
Drug classifications Antiinfectives (oral), antacids: decreased lactulose effect
Laxatives: do not use together (hepatic encephalopathy)
Drug/herb Flax, senna: increased laxative effect
Drug/lab test Blood glucose (diabetic patients): increase Blood ammonia: decrease
Nursing Considerations
Assessment -
Stool: Assess for amount, color, consistency - Monitor glucose levels in diabetic patients (increases) - Cause of constipation: Determine whether fluids, bulk, or exercise is missing from lifestyle - Monitor blood, urine, electrolytes if used often by patient; may cause diarrhea, hypokalemia, hypernatremia; check • I&O ratio to identify fluid loss - Assess cramping, rectal bleeding, nausea, vomiting; if these symptoms occur, product should be discontinued; identify cause of constipation: identify whether fluids, bulk, or exercise is missing from lifestyle - Hepatic encephalopathy: Monitor blood ammonia level (30-70 mg/100 ml); monitor for clearing of confusion, lethargy, restlessness, irritability (hepatic encephalopathy); may decrease ammonia level by 50%
Patient/family education - Discuss with patient that adequate fluid consumption is necessary - Teach patient that normal bowel movements do not always occur daily - Teach patient not to use in presence of abdominal pain, nausea, vomiting; tell patient to notify prescriber of unrelieved constipation or if symptoms of electrolyte imbalance occur: muscle cramps, pain, weakness, dizziness, excessive thirst - Teach patient not to use laxatives for long-term therapy; bowel tone will be lost - Do not give at bedtime as a laxative; may interfere with sleep - Notify prescriber if diarrhea occurs; may indicate overdosage
Evaluation
Positive therapeutic outcome: Decreased constipation; Decreased blood ammonia level; Clearing of mental state
Reference
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