Lithium with Methyldopa Interaction Details
Brand Names Associated with Lithium
- Eskalith®
- Eskalith® CR
- Lithium
- Lithobid®
Brand Names Associated with Methyldopa
- Aldochlor® (as a combination product containing Chlorothiazide, Methyldopa)
- Aldomet®
- Methyldopa
Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
Nov 21, 2023
Interaction Effect
An increased risk of toxic side effects
Interaction Summary
Concomitant use of lithium and methyldopa may increase the risk of toxic side effects. Several case reports have demonstrated that concurrent administration of methyldopa with lithium has resulted in signs of lithium toxicity .
Severity
Moderate
Onset
Delayed
Evidence
Theoretical
How To Manage Interaction
Concomitant use of lithium and methyldopa may increase the risk of toxic side effects.
Mechanism Of Interaction
Unknown
Literature Reports
A) A 42-year-old female on lithium carbonate therapy with therapeutic levels of lithium was treated for hypertension with methyldopa and developed swollen feet, ataxia, shakiness, slurred speech, and vocal soreness. Following discontinuation of both drugs, the patient's serum lithium dropped from 1.5 to 0.1 mEq/L within nine days and she showed no signs of tremor or ataxia, although slurred speech persisted .
B) A 45-year-old woman who was receiving lithium carbonate 900 mg daily for five years, was generally well controlled. The patient then began to show initial signs of manic decompensation and was admitted to the hospital where it was learned that she had been diagnosed as having hypertension. The patient was discharged on a regimen of 1800 mg of lithium carbonate and 1 g of methyldopa daily with serum levels of lithium below 1 mEq/L. Despite the therapeutic level of lithium, the patient began to show signs of lithium toxicity manifested by diarrhea, hand tremor, blurred vision, slurring speech and confusion. Methyldopa was discontinued and lithium was decreased to 1500 mg daily. The patient's serum lithium level was 1.4 mEq 10 days later. Lithium was reduced to 900 mg daily with a subsequent serum lithium level of 1 mEq/L .
C) Concomitant administration of lithium and methyldopa was reported to result in elevations of lithium serum levels and lithium toxicity in a 69-year-old woman. The interaction may occur secondary to methyldopa-induced sodium retention, resulting in reabsorption of lithium ions .
Lithium Overview
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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.
Methyldopa Overview
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Methyldopa is used to treat high blood pressure. Methyldopa is in a class of medications called antihypertensives. It works by relaxing the blood vessels so that blood can flow more easily through the body.
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High blood pressure is a common condition and when not treated, can cause damage to the brain, heart, blood vessels, kidneys and other parts of the body. Damage to these organs may cause heart disease, a heart attack, heart failure, stroke, kidney failure, loss of vision, and other problems. In addition to taking medication, making lifestyle changes will also help to control your blood pressure. These changes include eating a diet that is low in fat and salt, maintaining a healthy weight, exercising at least 30 minutes most days, not smoking, and using alcohol in moderation.
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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:
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.