Lamotrigine interactions to avoid

Drug interactions | Food interactions | Other interactions | Avoiding interactions | When to see a doctor

Lamotrigine is a generic medication approved by the U.S. Food and Drug Administration (FDA) to treat certain types of seizures, including those caused by Lennox-Gastaut syndrome. Medical professionals may also prescribe the immediate-release form of lamotrigine for the treatment of bipolar I disorder. Known by its brand name, Lamictal, lamotrigine is an antiepileptic drug available as an immediate-release tablet, extended-release tablet, orally disintegrating tablet, and chewable tablet. 

Although lamotrigine is an effective treatment option for those with epilepsy or bipolar disorder, it can interact with several other drugs. These include certain HIV medications, seizure medications, and valproic acid. Lamotrigine also interacts with cannabis. It’s important to be aware of lamotrigine interactions, as other drugs can affect lamotrigine’s effectiveness and cause or worsen side effects.

It is important to know that lamotrigine comes with a black box warning due to the risk of serious rashes. The FDA issues boxed warnings as the most serious warning. A boxed warning cautions doctors and patients about potentially harmful drug side effects. 

Let’s explore potential lamotrigine interactions. 

RELATED: Lamotrigine side effects and how to avoid them

Lamotrigine drug interactions

Lamotrigine can interact with several medications, including both prescription and over-the-counter drugs. Let’s review some of the potential lamotrigine drug interactions.

Certain types of hormonal birth control

Certain active ingredients in birth control pills may interact with lamotrigine. This includes estrogens, such as ethinyl estradiol, and progesterones, such as levonorgestrel. Combining lamotrigine with birth controls that contain these ingredients can lower the levels of lamotrigine in the body, which can decrease the effectiveness of the drug. What’s more, it may also lower the levonorgestrel levels in the body, which can weaken your protection against pregnancy. 

Also, many birth control packs contain a placebo week, which is a week where you aren’t taking any active drugs. This can cause a sharp increase in lamotrigine levels in the body, which puts you at higher risk of lamotrigine-related adverse effects. 

Due to this interaction, careful planning is required if you’re looking to combine lamotrigine treatment with birth control. Before starting lamotrigine, let your healthcare provider know if you take birth control so they can determine if the two drugs will interact. If they do, your provider may need to adjust your lamotrigine dose. Alternatively, healthcare providers may recommend birth control options that don’t contain these specific ingredients or contraceptives that don’t contain any hormones. 

Certain seizure medications

Certain anti-seizure medications can affect the levels of lamotrigine in the body. 

In particular, Tegretol (carbamazepine), Dilantin (phenytoin), primidone, and phenobarbital increase the breakdown and clearance of lamotrigine in the body. This means lamotrigine can’t reach as high levels in the body as it usually would, which makes the drug less effective. This may result in more frequent seizures or uncontrolled symptoms of bipolar disorder. 

On the other hand, Depakene (valproic acid) and Depakote (divalproex), two other commonly prescribed anticonvulsant medications, may also interact with lamotrigine by increasing the lamotrigine levels in the body. This can increase the risk of mild or serious side effects of lamotrigine, such as dizziness, double vision, problems with coordination, and a serious skin rash. 

Due to this risk, healthcare providers may adjust your dose of lamotrigine if these two medications are combined. 

Certain HIV medications

Human immunodeficiency virus (HIV) is typically managed with antiretroviral therapy (ART). However, certain HIV medications can increase the breakdown of lamotrigine in the body and lower lamotrigine blood levels. This can make lamotrigine less effective at managing seizures or bipolar disorder. 

Examples of HIV medications that can interact with lamotrigine include: 

• Kaletra (lopinavir/ritonavir)
• Reyataz (atazanavir)
• Norvir (ritonavir) 

Rifampin

Rifampin (Rifadin or Rimactane) is the most commonly used tuberculosis (TB) antibiotic. However, it may also be used to clear meningitis bacteria from the nose or throat. 

Rifampin can speed up the breakdown of lamotrigine in the body, which results in lower blood concentrations of lamotrigine. This decreases the effectiveness of lamotrigine. 

Dofetilide

Tikosyn (dofetilide) is a medication for arrhythmias (abnormal heart rhythms). Although it’s a highly effective drug, small changes in dofetilide blood levels can cause serious side effects or a decrease in effectiveness. 

Combining lamotrigine with dofetilide can slow the clearance of dofetilide from the body. As a result, dofetilide blood levels can increase. This puts you at increased risk for serious side effects such as QT prolongation, which is the time it takes for the lower chambers of the heart to contract and then fully relax, and other life-threatening abnormal heart rhythms. 

Due to this risk, it’s not recommended to take lamotrigine and dofetilide together. 

Metformin

Similar to its interaction with dofetilide, lamotrigine can also interact with metformin by slowing its clearance from the body. This results in higher-than-usual blood levels of metformin, which increases the risk of severe side effects such as lactic acidosis (a buildup of lactic acid in the blood). If these drugs are prescribed together, your healthcare provider will likely adjust your metformin dose. 

Acetaminophen

Acetaminophen, commonly referred to by its brand name Tylenol, is an over-the-counter (OTC) pain reliever. According to The Prescribers’ Digital Reference (PDR), acetaminophen may interact with lamotrigine by increasing its clearance from the body. This can decrease lamotrigine’s effectiveness in managing seizures or symptoms of bipolar disorder. 

Because acetaminophen is a common ingredient in many OTC cough, cold, and sleep medications, it’s important to discuss the use of any new OTC drugs with a healthcare professional. If you’re taking lamotrigine, they can help determine if you need a dosage adjustment or recommend an alternative treatment that doesn’t contain acetaminophen. 

RELATED: Lamotrigine alternatives: What can I take instead of lamotrigine?

Lamotrigine food interactions

Some medications can interact with certain foods. Luckily, no known foods affect how lamotrigine works or its absorption. 

There is some evidence that certain diets, such as a ketogenic diet, can help control seizures in some people with epilepsy. It’s most commonly prescribed to children with seizures that aren’t controlled by medications. 

Other lamotrigine interactions

In addition to drugs, lamotrigine may interact with cannabis and certain health conditions. 

Lamotrigine and CBD

According to PDR, cannabis, which is often referred to as marijuana, can interact with lamotrigine. Combining these substances can increase the levels of lamotrigine in the body. As a result, you may be at higher risk of side effects from lamotrigine.

Be sure to tell your healthcare provider if you use cannabis or cannabis products, such as cannabidiol (CBD). To help minimize this interaction, they may reduce your lamotrigine dose. 

Lamotrigine and disease

If you have certain health conditions, use caution when taking lamotrigine. You may be at higher risk of side effects. These include people with the following health conditions or health factors:

• Depression or mood problems
• Suicidal thoughts or behavior
• Kidney problems
• History of heart problems or irregular heartbeats
• Currently pregnant or breastfeeding
• Age 65 years or older
• Past allergic reaction to lamotrigine or any of its ingredients

How to minimize lamotrigine interactions

There are a few ways you can help minimize lamotrigine interactions. 

• Consult a healthcare provider. Before starting new medications, including over-the-counter or prescription drugs, vitamins, or supplements, consult a healthcare provider, such as a doctor or pharmacist. They can help determine if the drug will interact with your current medications. 
• Keep a list of medications and medical conditions. Maintain an updated list of all health conditions and current medications, vitamins, and supplements. This way, you can share the list with a healthcare professional so they can screen for interactions. 
• Understand and recognize warning signs. A lamotrigine interaction may cause new or worsening side effects or changes in the symptoms of your medical conditions. If you notice any of these signs, seek medical advice. 

When to talk to a healthcare provider about lamotrigine interactions

Although several lamotrigine interactions were discussed here, this article doesn’t contain a complete list of all lamotrigine interactions. It’s best to communicate openly with healthcare providers about all medications, supplements, and medical conditions before starting lamotrigine treatment. This will help ensure proper management and monitoring of your health.