7 Lithium Interactions You Should Know About

If you have bipolar disorder, you may be taking lithium (Lithobid) to help with your symptoms. Lithium has been prescribed in the U.S. for over 50 years. It’s also a first-choice medication for treating bipolar disorder. But it comes with many side effects and interactions.

Lithium is sometimes taken with other medications for bipolar disorder. So, potential interactions can be common. However, several lithium interactions can affect lithium levels in your blood. This can increase the risk of side effects and lithium toxicity. And certain dietary changes, including your salt intake, can have a similar effect.

Fortunately, many lithium interactions can be managed by monitoring your blood work. If needed, your dose can be adjusted. But there are still several important interactions that you should know about. Let’s review a few examples and how to manage them.

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1. Diuretics

Diuretics (“water pills”) treat health conditions like high blood pressure and fluid buildup (edema). They work by helping you pee out excess fluid from your body. Examples of diuretics include loop diuretics, like furosemide (Lasix). Thiazide diuretics like hydrochlorothiazide (Microzide) are also diuretics.

When taken together, diuretics can increase lithium levels in your blood. They do this by decreasing how much lithium your kidneys remove from your body. This can result in lithium toxicity if your levels get too high.

Early symptoms of lithium toxicity can include diarrhea, lightheadedness, and drowsiness. Blurred vision and ringing in your ears (tinnitus) can happen at higher levels, among other side effects. In severe cases, lithium toxicity can cause seizures, coma, and death. Get emergency medical attention if these symptoms develop.

Your healthcare provider will monitor your lithium levels during treatment. They may want to check them more often when you’re starting, stopping, or adjusting the dose of your diuretic. If needed, they’ll adjust your lithium dose. 

2. NSAIDs

Nonsteroidal anti-inflammatory drugs (NSAIDs) are used to treat pain and inflammation. Several NSAIDs, like ibuprofen (Advil, Motrin) and naproxen (Aleve, Naprosyn), are available over the counter. Others, like meloxicam (Mobic), are prescription only.

NSAIDs can also decrease how much lithium is removed by your kidneys. This combination can put you at higher risk for lithium side effects and toxicity. Your healthcare provider can suggest safer alternatives for relief from pain and inflammation.

But if they tell you it’s OK to take an NSAID, they may want to watch your lithium levels more closely. In this case, let them know if you change how often you’re taking NSAIDs.

3. Blood pressure medications

In addition to diuretics, other blood pressure medications can affect lithium levels. These include angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs). ACE inhibitors include medications like lisinopril (Zestril). And valsartan (Diovan) is an example of an ARB.

Both ACE inhibitors and ARBs can increase lithium levels in your blood. If your levels get too high, your healthcare provider may need to lower your lithium dose. 

Calcium channel blockers (CCBs) are also used to treat high blood pressure, as well as chest pain and heart rhythm problems. Examples include diltiazem (Cardizem) and verapamil. CCBs can interact with lithium in a different way.

This combination can increase the risk of lithium side effects in your brain and nerves. For example, tremors, tinnitus, and coordination problems may be more likely. Let your healthcare provider know if these symptoms develop. 

4. Metronidazole

Metronidazole (Flagyl) is an oral antibiotic used to treat different types of bacterial infections. It also decreases how much lithium is removed by your kidneys.

Depending on the type of infection you’re treating, you’ll typically take metronidazole for 5 to 10 days. Your healthcare provider may want to monitor your lithium levels more closely during treatment. If your levels are too high, they may need to adjust your lithium dose. 

5. Certain diet changes

Before making significant changes to your diet, you should talk with your healthcare provider first. That’s because certain foods and beverages can influence lithium levels and side effects in your body. This includes your intake of caffeine, salt, and alcohol.

Caffeine can decrease lithium levels in the blood, which could lead to a less effective treatment. Try to maintain a consistent caffeine intake while you’re taking lithium. This helps keep the medication levels steady.

Salt intake can also influence lithium levels. This is because the sodium found in salt can affect how your kidneys remove lithium from your body. Consuming less salt in your diet increases lithium levels. And consuming more salt decreases lithium levels. Similar to caffeine, you should try to keep a consistent amount of salt in your diet.

Alcohol can worsen lithium side effects such as dizziness or drowsiness. It can also worsen symptoms of bipolar disorder. What’s more, alcohol can cause dehydration, putting you at higher risk for lithium toxicity. Because of this, you should avoid alcohol while taking lithium.

6. Medications that increase serotonin

Serotonin is a chemical in your body that’s used for many functions, like regulating your mood. Some medications and supplements increase serotonin levels in your brain. Common examples include:

• Selective serotonin reuptake inhibitors (SSRIs) like sertraline (Zoloft)

• Serotonin and norepinephrine reuptake inhibitors (SNRIs) like venlafaxine (Effexor XR)

• Monoamine oxidase inhibitors (MAOIs) like selegiline (Zelapar, Emsam)

• Tricyclic antidepressants (TCAs) like amitriptyline     

• Some opioids, like tramadol (Ultram, ConZip)

• St. John’s wort 

• Triptans like sumatriptan (Imitrex)

However, too much serotonin in your brain can be dangerous and lead to a condition called serotonin syndrome. Mild symptoms are most common, and include symptoms like tremors, a fast heartbeat, and sweating. Severe symptoms include high fever, severe agitation, and very high blood pressure.

Combining lithium with other medications or supplements that increase serotonin can make serotonin syndrome more likely. But this combination can be relatively common. For example, antidepressants like SSRIs are sometimes taken with lithium for bipolar disorder.

Your healthcare provider can review your current medication list to identify potential interactions ahead of time. Let them know right away if you develop symptoms of serotonin syndrome. If any symptoms are severe or feel life-threatening, get immediate medical attention. 

7. Antipsychotic medications

Antipsychotic medications treat health conditions like schizophrenia, bipolar disorder, and depression. Examples include older typical antipsychotics, like haloperidol (Haldol), and newer atypical antipsychotics, like risperidone (Risperdal). 

Neurological side effects have been reported in people taking antipsychotics with lithium. These effects range from uncontrollable body movements to a rare condition called neuroleptic malignant syndrome (NMS). Sudden fever, rigid muscles, and confusion can be symptoms of NMS. Get immediate medical attention if these occur.

Like antidepressants, antipsychotics are sometimes prescribed in combination with lithium. In these situations, your healthcare provider will watch for signs of an interaction. If symptoms occur, they may adjust your dose or change your medications.

When should I contact my healthcare provider about a lithium interaction?

Because lithium has many interactions, your healthcare provider and pharmacist will likely address them upfront. And they’ll monitor your lithium levels throughout treatment, too. This is to ensure your lithium dosage is safe and effective with other medications you’re taking.

But you may start, stop, or change other medications while taking lithium. These changes may affect your lithium levels. The same is true for dietary changes with salt and caffeine. So, it’s important to let your healthcare provider know about these changes. They may want to monitor you more closely.

If you’re worried about lithium interactions, let your healthcare provider know. Even though they may already be aware of the interaction, it’s best to double-check. If you’re having serious symptoms like severe tremors, confusion, or blurry vision, seek immediate medical care.

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Written by:

Austin Ulrich, PharmD, BCACP

Austin Ulrich, PharmD, BCACP, is a board-certified ambulatory care clinical pharmacist. In his early career, he provided direct patient care in a variety of settings, including hospital and community pharmacies, and in a primary care clinic as a clinical pharmacist.

Edited by:

Alyssa Billingsley, PharmD

Alyssa Billingsley, PharmD, is the director of pharmacy content for GoodRx. She has over a decade of experience as a pharmacist and has worked in clinical, academic, and administrative roles.

Reviewed by:

Joshua Murdock, PharmD, BCBBS

Joshua Murdock, PharmD, BCBBS, is a licensed pharmacist in Arizona, Colorado, and Rhode Island. He has worked in the pharmacy industry for more than 10 years and currently serves as a pharmacy editor for GoodRx.

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