lactulose (Rx)

Brand and Other Names:Enulose, Kristalose, more...Constulose, Generlac
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Dosing & Uses

AdultPediatric

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

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Interactions

Interaction Checker

and lactulose

No Results

     activity indicator 
    No Interactions Found
    Interactions Found

    Contraindicated

      Serious - Use Alternative

        Significant - Monitor Closely

          Minor

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            Contraindicated (0)

              Serious - Use Alternative (0)

                Monitor Closely (6)

                • 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.

                Minor (0)

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                  Adverse Effects

                  Frequency Not Defined

                  Dehydration

                  Diarrhea

                  Excessive bowel activity

                  Hypernatremia

                  Hypokalemia

                  Nausea

                  Vomiting

                  Abdominal cramping

                  Abdominal distention

                  Belching

                  Flatulence

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                  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

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                  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.

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                  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)

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                  Images

                  BRAND FORM. UNIT PRICE PILL IMAGE
                  Generlac oral
                  -
                  10 gram/15 mL solution
                  Generlac oral
                  -
                  10 gram/15 mL solution
                  Enulose oral
                  -
                  10 gram/15 mL solution
                  Constulose oral
                  -
                  10 gram/15 mL solution
                  Constulose oral
                  -
                  10 gram/15 mL solution
                  Kristalose oral
                  -
                  20 gram miscellaneous
                  Kristalose oral
                  -
                  10 gram miscellaneous
                  Kristalose oral
                  -
                  20 gram miscellaneous
                  lactulose 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

                  Copyright © 2010 First DataBank, Inc.

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                  Patient Handout

                  Patient Education
                  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, usually once daily for constipation, or as directed by your doctor. 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. Dosage is based on your medical condition and response to therapy.It may take up to 48 hours to have a bowel movement. Inform your doctor if your condition persists or worsens.

                  SIDE EFFECTS: Gas, bloating, burping, stomach rumbling/pain, nausea, and cramps may occur. If any of these effects persist or worsen, notify 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: diarrhea, vomiting, muscle cramps/weakness, irregular heartbeat, mental/mood changes, seizures, severe or persistent stomach/abdominal pain, 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 (e.g., a diet that includes few or no milk products), certain other bowel problem (bowel obstruction), diabetes.The elderly may be at a greater risk for loss of blood minerals (e.g., potassium, sodium) while using this drug, especially if they are using it for an extended time.Do not take any other laxative medications while taking this drug. Frequent use or overuse of laxatives can cause dehydration. This is especially likely to occur in children or the elderly. Contact your doctor right away if you develop any of the following symptoms of dehydration: muscle weakness, muscle cramps, dizziness.Before having surgery or other procedures (e.g., electrocautery), tell your doctor or surgeon that you are using this medication.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.During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.It is not known whether 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 an extended time, laboratory and/or medical tests (e.g., blood mineral levels) should be performed periodically to monitor your progress or check for side effects. 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 2021. Copyright(c) 2021 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.

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                  Formulary

                  FormularyPatient Discounts

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                  The above information is provided for general informational and educational purposes only. Individual plans may vary and formulary information changes. Contact the applicable plan provider for the most current information.

                  Tier Description
                  1 This drug is available at the lowest co-pay. Most commonly, these are generic drugs.
                  2 This drug is available at a middle level co-pay. Most commonly, these are "preferred" (on formulary) brand drugs.
                  3 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs.
                  4 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
                  5 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
                  6 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
                  NC NOT COVERED – Drugs that are not covered by the plan.
                  Code Definition
                  PA Prior Authorization
                  Drugs that require prior authorization. This restriction requires that specific clinical criteria be met prior to the approval of the prescription.
                  QL Quantity Limits
                  Drugs that have quantity limits associated with each prescription. This restriction typically limits the quantity of the drug that will be covered.
                  ST Step Therapy
                  Drugs that have step therapy associated with each prescription. This restriction typically requires that certain criteria be met prior to approval for the prescription.
                  OR Other Restrictions
                  Drugs that have restrictions other than prior authorization, quantity limits, and step therapy associated with each prescription.
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                  Medscape prescription drug monographs are based on FDA-approved labeling information, unless otherwise noted, combined with additional data derived from primary medical literature.