Dosing & Uses
Dosage Forms & Strengths
oral/rectal solution
- 10g/15mL
packet
- 10g
- 20g
Constipation
Solution: 15-30 mL (10-20 g) PO once daily; may be increased to 60 mL (40 g) once daily
Crystals: 10-20 g PO qDay; may increase to 40 g/day
Portal Systemic Encephalopathy
Prophylaxis
30-45 mL (20-30 g) PO q6-8hr, adjusted until 2-3 soft stools/day; if acute, may be given q1-2hr until 2-3 soft stools/day
Treatment
20-30 g (30-45 mL) PO q1hr to induce rapid defecation; reduced to 20-30 g q6-8hr after defecation achieved; titrated to produce 2-3 soft stools/day
300 mL (200 g) PR with 700 mL water or NS, retained for 30-60 minutes; may be repeated q4-6hr; transition to oral treatment before discontinuance of rectal administration
Dosage Forms & Strengths
oral/rectal solution
- 10g/15mL
packet
- 10g
- 20g
Constipation
0.7-2 g/kg/day (1-3 mL/kg/day) PO in divided doses; not to exceed 40 g/day (60 mL/day)
Portal Systemic Encephalopathy
Prophylaxis
Infants: 2.5-10 mL/day (1.7-6.67 g/day) PO in divided doses; titrated to produce 2-3 soft stools/day
Children and adolescents: 40-90 mL/day (26.7-60 g/day) PO in divided doses; titrated to produce 2-3 soft stools/day
Interactions
Interaction Checker
No Results
Contraindicated
Serious - Use Alternative
Significant - Monitor Closely
Minor
Contraindicated (0)
Serious - Use Alternative (0)
Monitor Closely (7)
- aluminum hydroxide
aluminum hydroxide decreases effects of lactulose by pharmacodynamic antagonism. Use Caution/Monitor.
- calcium carbonate
calcium carbonate decreases effects of lactulose by pharmacodynamic antagonism. Use Caution/Monitor.
- deflazacort
lactulose and deflazacort both decrease serum potassium. Use Caution/Monitor.
- dichlorphenamide
dichlorphenamide and lactulose both decrease serum potassium. Use Caution/Monitor.
dichlorphenamide, lactulose. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Both drugs can cause metabolic acidosis. - sodium bicarbonate
sodium bicarbonate decreases effects of lactulose by pharmacodynamic antagonism. Use Caution/Monitor.
- sodium citrate/citric acid
sodium citrate/citric acid decreases effects of lactulose by pharmacodynamic antagonism. Use Caution/Monitor.
- warfarin
lactulose increases effects of warfarin by unspecified interaction mechanism. Use Caution/Monitor.
Minor (0)
Adverse Effects
Frequency Not Defined
Dehydration
Diarrhea
Excessive bowel activity
Hypernatremia
Hypokalemia
Nausea
Vomiting
Abdominal cramping
Abdominal distention
Belching
Flatulence
Warnings
Contraindications
Galactosemia (patients require low-galactose diet)
Cautions
Diabetes (preparation contains lactose and galactose)
Monitor for electrolyte imbalance when drug is used for >6 months or in patients predisposed to electrolyte abnormalities
Avoid using other laxatives concomitantly
Inadequate response possible when taken concomitantly with anti-infective
Pregnancy & Lactation
Pregnancy category: B
Lactation: Unknown whether drug is distributed into milk; use with caution
Pregnancy Categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk. C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done. D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk. X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist. NA: Information not available.Pharmacology
Mechanism of Action
Constipation: Hyperosmotic agent increases stool water contents, softens stool, promotes peristalsis, and reduces blood ammonia concentration
Portal systemic encephalopathy: Breakdown of lactulose to organic acids by colonic bacteria acidifies colonic contents, thereby subsequently inhibiting diffusion of ammonia back to blood; agent also enhances diffusion of NH3 from blood into gut, where it is converted to NH4+
Absorption
Bioavailability: <3% absorbed
Onset: 24-48 hr
Metabolism
Absorbed lactulose is not metabolized; unabsorbed lactulose is extensively metabolized to organic acids by colonic bacteria
Metabolites: Lactic acid (main), formic acid, acetic acid (all active)
Elimination
Excretion: Urine (absorbed lactulose), feces and bile (unabsorbed lactulose and metabolites; minimal)
Images
| BRAND | FORM. | UNIT PRICE | PILL IMAGE |
|---|---|---|---|
| Generlac oral - | 10 gram/15 mL solution |  | |
| Generlac oral - | 10 gram/15 mL solution |  | |
| Constulose oral - | 10 gram/15 mL solution |  | |
| Constulose oral - | 10 gram/15 mL solution |  | |
| lactulose oral - | 20 gram/30 mL solution |  | |
| lactulose oral - | 10 gram/15 mL solution |  | |
| lactulose oral - | 10 gram/15 mL solution |  | |
| lactulose oral - | 10 gram/15 mL solution |  | |
| lactulose oral - | 10 gram/15 mL solution |  | |
| lactulose oral - | 10 gram/15 mL solution |  | |
| lactulose oral - | 10 gram/15 mL solution |  | |
| lactulose oral - | 10 gram/15 mL solution |  | |
| lactulose oral - | 10 gram/15 mL solution |  | |
| lactulose oral - | 10 gram/15 mL solution |  | |
| lactulose oral - | 10 gram/15 mL solution |  | |
| lactulose oral - | 10 gram/15 mL solution |  | |
| Enulose oral - | 10 gram/15 mL solution |  | |
| Kristalose oral - | 20 gram miscellaneous |  | |
| Kristalose oral - | 10 gram miscellaneous |  | |
| Kristalose oral - | 20 gram miscellaneous |  |
Copyright © 2010 First DataBank, Inc.
Patient Handout
lactulose oral
LACTULOSE (LAXATIVE) - ORAL
(LACK-tew-lohss)
COMMON BRAND NAME(S): Cephulac, Chronulac, Constulose
USES: This medication is a laxative used to treat constipation. It may help to increase the number of bowel movements per day and the number of days you have a bowel movement. Lactulose is a colonic acidifier that works by increasing stool water content and softening the stool. It is a man-made sugar solution.
HOW TO USE: Take this medication by mouth as directed by your doctor, usually once daily for constipation. If you are taking the solution, to improve the taste, you may mix it into fruit juice, water, milk, or a soft dessert. If you are using the crystals in packets, dissolve the contents of the packet in half a glass of water (4 ounces or 120 milliliters), or as directed by your doctor.Use this medication regularly in order to get the most benefit from it. Remember to take it at the same time each day. The dosage is based on your medical condition and response to treatment.It may take up to 48 hours to have a bowel movement. Tell your doctor if your condition lasts or gets worse.
SIDE EFFECTS: Gas, bloating, burping, stomach rumbling/pain, nausea, and cramps may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.Tell your doctor right away if you have any serious side effects, including: stomach/abdominal pain that is severe or doesn't go away, diarrhea, vomiting, muscle cramps/weakness, irregular heartbeat, mental/mood changes, seizures, bloody stools, rectal bleeding.A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.In the US -Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.
PRECAUTIONS: Before taking lactulose, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.Before using this medication, tell your doctor or pharmacist your medical history, especially of: a low galactose diet (such as a diet that includes few or no milk products), certain other bowel problem (bowel obstruction), diabetes.Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).This medication contains different sugars. If you have diabetes, this medication may affect your blood sugar. Check your blood sugar regularly as directed and share the results with your doctor. Your doctor may need to adjust your diabetes medication, exercise program, or diet.Older adults may be at a greater risk for loss of blood minerals (such as potassium, sodium) while using this drug, especially if they are using it for an extended time.During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.It is unknown if this drug passes into breast milk. Consult your doctor before breast-feeding.
DRUG INTERACTIONS: Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.Some products that may interact with this drug are: antacids containing aluminum and/or magnesium, other laxatives.
OVERDOSE: If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center. Symptoms of overdose may include: severe stomach cramps, diarrhea.
NOTES: Do not share this product with others.If you use this product for a long time, lab and/or medical tests (such as blood mineral levels) should be done while you are taking this medication. Keep all medical and lab appointments. Consult your doctor for more details.
MISSED DOSE: If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.
STORAGE: Store at room temperature away from light and moisture. Do not freeze because this will make the medication too thick to pour. If it becomes frozen, warm it to room temperature until it is pourable again. A normal darkening of color may occur. If too much darkening occurs and you cannot swallow it, discard the medication and get a refill. Do not store in the bathroom. Keep all medications away from children and pets.Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.
Information last revised August 2023. Copyright(c) 2023 First Databank, Inc.
IMPORTANT: HOW TO USE THIS INFORMATION: This is a summary and does NOT have all possible information about this product. This information does not assure that this product is safe, effective, or appropriate for you. This information is not individual medical advice and does not substitute for the advice of your health care professional. Always ask your health care professional for complete information about this product and your specific health needs.
Formulary
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