Lithium with Lactulose Interaction Details

Brand Names Associated with Lithium

Brand Names Associated with Lactulose

Medical Content Editor Dr. Brian Staiger, PharmD
Last updated Nov 21, 2023

Interaction Effect

Increased lithium concentrations and lithium toxicity

Interaction Summary

Use caution when prescribing lactulose to patients who take lithium. Concomitant use of lithium and lactulose may cause elevated lithium plasma concentrations. Serum lithium levels greater than 1.5 mEq/L were reported in 3 patients who were taking lithium and lactulose concomitantly. If using both drugs together, monitor for increased lithium side effects and maintain adequate hydration.

Severity

Moderate

Onset

Unspecified

Evidence

Probable

How To Manage Interaction

Use caution when prescribing lactulose to patients who take lithium. Concomitant use of lithium and lactulose may cause elevated lithium plasma concentrations. If using both drugs together, monitor for increased lithium side effects and maintain adequate hydration.

Mechanism Of Interaction

Volume depletion increase and renal tubular reabsorption of lithium

Literature Reports

A) Serum lithium levels were greater than 1.5 mEq/L in 3 patients who were taking lithium and lactulose concomitantly. In the first case, a 47-year-old male had a lithium level of 1.6 mEq/L with a serum creatinine level of 0.57 mg/dL after taking two doses of lactulose 30 mg along with lithium 300 mg twice daily. No adverse outcomes were reported and a later lithium level was 1.2 mEq/L. The probability of adverse drug reaction was 6 on the Naranjo scale. The second case was a 45-year-old woman who began taking 450 mg lithium in the morning and 600 mg at night along with 30 mL of lactulose for 3 days. Nine days later her lithium level reached 2.4 mEq/L. She reported mild fatigue, but no other signs of lithium toxicity. After discontinuation and observation in a hospital, her lithium levels normalized. This case scored a 3 on the Naranjo scale; it is notable that she was also taking hydrochlorothiazide and lisinopril. The third case involved a 48-year-old woman who was increased to lithium 900 mg twice daily and received 5 doses of lactulose 30 mg over 2 days. She reported drowsiness and tremor and her lithium level reached 1.6 mEq/L. After reducing her lithium dose to 300 mg in the morning and 600 mg in the evening, her lithium level normalized. The Naranjo score on this case was 4; notably, she was also taking benazepril 

Lithium Overview

• Lithium is used to treat and prevent episodes of mania (frenzied, abnormally excited mood) in people with bipolar disorder (manic-depressive disorder; a disease that causes episodes of depression, episodes of mania, and other abnormal moods). Lithium is in a class of medications called antimanic agents. It works by decreasing abnormal activity in the brain.

Lactulose Overview

• Lactulose is a synthetic sugar used to treat constipation. It is broken down in the colon into products that pull water out from the body and into the colon. This water softens stools. Lactulose is also used to reduce the amount of ammonia in the blood of patients with liver disease. It works by drawing ammonia from the blood into the colon where it is removed from the body.

• This medication is sometimes prescribed for other uses; ask your doctor or pharmacist for more information.

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Definitions

Severity Categories

Contraindicated

These drugs, generally, should not be used together simultaneously due to the high risk of severe adverse effects. Combining these medications can lead to dangerous health outcomes and should be strictly avoided unless otherwise instructed by your provider.

Major

This interaction could result in very serious and potentially life-threatening consequences. If you are taking this drug combination, it is very important to be under close medical supervision to minimize severe side effects and ensure your safety. It may be necessary to change a medication or dosage to prevent harm.

Moderate

This interaction has the potential to worsen your medical condition or alter the effectiveness of your treatment. It's important that you are monitored closely and you potentially may need to make adjustments in your treatment plan or drug dosage to maintain optimal health.

Minor

While this interaction is unlikely to cause significant problems, it could intensify side effects or reduce the effectiveness of one or both medications. Monitoring for changes in symptoms and your condition is recommended, and adjustments may be made if needed to manage any increased or more pronounced side effects.

Onset

Rapid: Onset of drug interaction typically occurs within 24 hours of co-administration.

Delayed: Onset of drug interaction typically occurs more than 24 hours after co-administration.

Evidence

Level of documentation of the interaction.

Established: The interaction is documented and substantiated in peer-reviewed medical literature.

Theoretical: This interaction is not fully supported by current medical evidence or well-documented sources, but it is based on known drug mechanisms, drug effects, and other relevant information.

How To Manage The Interaction

Provides a detailed discussion on how patients and clinicians can approach the identified drug interaction as well as offers guidance on what to expect and strategies to potentially mitigate the effects of the interaction. This may include recommendations on adjusting medication dosages, altering the timing of drug administration, or closely monitoring for specific symptoms.

It's important to note that all medical situations are unique, and management approaches should be tailored to individual circumstances. Patients should always consult their healthcare provider for personalized advice and guidance on managing drug interactions effectively.

Mechanism Of Interaction

The theorized or clinically determined reason (i.e., mechanism) why the drug-drug interaction occurs.

Disclaimer: The information provided on this page is for informational purposes only and should not be considered medical advice. Always consult with a qualified healthcare professional regarding your specific circumstances and medical conditions.

Where Does Our Information Come From?

Information for our drug interactions is compiled from several drug compendia, including:

• Gold Standard Drug Database
• Micromedex
• Lexicomp
• DrugBank

The prescribing information for each drug, as published on DailyMED, is also used. 

Individual drug-drug interaction detail pages contain references specific to that interaction. You can click on the reference number within brackets '[]' to see what reference was utilized.

The information posted is fact-checked by HelloPharmacist clinicians and reviewed quarterly.