Side Effects of Trileptal (Oxcarbazepine)

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Trileptal (oxcarbazepine) is an anticonvulsant that is sometimes prescribed off-label as a mood stabilizer for people with bipolar disorder, to reduce the risk of mania or rapid cycling. While the effectiveness of Trileptal for this purpose is unclear, this medication can come with side effects.

Understanding the potential side effects of Trileptal is important before beginning this medication. Here we share some of the most common and rarer but serious side effects of Trileptal, along with warnings associated with this drug.

Some people experience serious and potentially life-threatening side effects when taking Trileptal. If you experience any of these effects—which include low blood sodium, allergic reaction, and suicidal thoughts—seek immediate medical attention.

Potential Trileptal Side Effects

Not everyone will experience side effects when taking Trileptal, and some people experience more effects or more severe effects than others. Additionally, some side effects of Trileptal are common and mild while others are rarer but severe.

Being aware of both helps you know what type of mild effects you may experience, which you can discuss with your healthcare provider if they are problematic, along with identifying which side effects may be serious enough to seek immediate medical attention.

Common Side Effects

According to the U.S. Food and Drug Administration (FDA), the most common side effects of Trileptal include:

  • Dizziness
  • Double vision or other problems with vision
  • Feeling tired
  • Nausea and/or vomiting
  • Problems with walking or coordination
  • Rash
  • Sleepiness
  • Trembling

In a 2011 review study in the Cochrane Database of Systematic Reviews on the use of Trileptal in people with bipolar disorder, the most frequent side effects reported were dizziness, sedation, and blurry vision.

Serious Side Effects

There are some serious side effects of Trileptal you should know about if you are taking or considering taking the medication.

Call 911 or seek medical care immediately if you experience any of these serious and potentially life-threatening side effects of Trileptal.

Low Blood Sodium

Trileptal can cause the sodium in your blood to be low, which is a condition called hyponatremia. Factors that can affect a person's risk of developing hyponatremia when taking oxcarbazepine include being older, female gender, dosage, combining this medication with other drugs, and taking it long-term.

According to the FDA, symptoms of hyponatremia include:

  • Confusion
  • Headache
  • Low energy
  • Nausea
  • Seizures

Allergic Reaction

Another potential serious side effect is an allergic reaction. Symptoms of an allergic reaction may include:

  • Problems breathing
  • Rash
  • Swelling of the face, eyes, lips, or tongue

Serious and potentially fatal rashes, like Stevens-Johnson syndrome and toxic epidermal necrolysis, can occur as a result of taking Trileptal.

Cellular Reactions

Trileptal can also affect the liver and blood cells. Symptoms or signs of these side effects may include:

  • Frequent infections or infections that don't go away
  • Severe fatigue or weakness
  • Severe muscle pain
  • Unusual bruising or bleeding
  • Yellowing of the skin or eyes

Suicidal Ideation

Finally, similar to other anti-seizure medications, Trileptal may lead to thoughts or actions of suicide. This side effect is rare, occurring in about 1 in 500 people, according to the FDA. If you notice any changes in your mental health, mood, or thoughts, reach out to your healthcare provider.

If you are having suicidal thoughts, contact the National Suicide Prevention Lifeline at 988 for support and assistance from a trained counselor. If you or a loved one are in immediate danger, call 911.

For more mental health resources, see our National Helpline Database.

Oxcarbazepine Warnings

There are some important warnings you should know about before and while taking Trileptal. Remember to speak with your healthcare provider about how to approach each of these situations so you can take the medication as safely as possible.

  • Stopping the medication: Don't suddenly stop taking Trileptal without consulting a physician as that could worsen seizures in those with epilepsy. Also, missing doses may result in a relapse of bipolar disorder symptoms.
  • Birth control: Hormonal contraceptives may not be as effective while you're taking Trileptal.
  • Pregnancy: If you are pregnant or become pregnant, it's important to speak to your healthcare provider as Trileptal could be harmful to an unborn baby. It can also end up in breast milk, so you and your provider will need to weigh the risks and benefits of nursing while taking Trileptal.
  • Driving: Since Trileptal can cause drowsiness, dizziness, and other side effects that could be dangerous, be cautious about driving. Refrain from doing so until you're familiar with how the medication affects you.
  • Alcohol and other drugs: Similarly, using alcohol and other depressant drugs while taking Trileptal may exacerbate side effects such as drowsiness.
  • Other medications: Trileptal can interact with other medications, so always tell your healthcare provider what else you're taking. Trileptal may decrease levels of certain blood pressure medications, medications to prevent organ transplant rejection, and oral contraceptives, and may increase the levels of certain seizure medications.
  • Mental health: If you notice changes in your mood and mental health while taking Trileptal—such as depression, anxiety, or irritability—reach out to your healthcare provider. A potentially serious side effect of taking the medication is suicidal thoughts or actions.

Trileptal Dosages

The usual dose of Trileptal ranges between 900 mg and 1,200 mg per day. People generally begin on a low dose that is gradually increased in slow increments over the course of several weeks until the optimal dose is reached. 

The starting dose usually begins at 300 mg twice per day. The maximum daily dose for controlling seizures is 2,400 mg per day.

However, only your healthcare provider can determine what the right dose is for you. Older adults and people who have renal impairment may need lower dosages. You should always take your medication as directed.

Oxcarbazepine vs. Carbamazepine

Trileptal (oxcarbazepine) is an analog to Tegretol (carbamazepine), meaning they share a similar chemical structure. Both are anti-seizure medications and Tegretol (carbamazepine) is also used sometimes to treat bipolar disorder.

Many people who are allergic to carbamazepine have reactions to oxcarbazepine as well, so be sure to tell your primary care physician if you're allergic to carbamazepine.

While they have similar side effect profiles, there are some subtle differences, according to the 2011 Cochrane review. For instance, a rash is less common with oxcarbazepine than with carbamazepine. Also, hyponatremia may be more common in people who take oxcarbazepine versus carbamazepine, especially if that person is older and has a low blood sodium level at baseline.

Notably, a 2020 study published in Yonsei Medical Journal found a lower incidence of more severe adverse side effects in those who took oxcarbazepine versus carbamazepine.


It's important to know that other side effects not listed above may occur in some people. This is not intended to be an all-inclusive list or to replace information provided by your primary care provider. If you notice any other side effects or have any concerns when taking Trileptal, let your provider know.

Also, never start or stop a medication without discussing the risks and benefits with your physician. Additionally, follow up with your physician once you are prescribed this or any medication to talk about any side effects and how well the medication is working for you.

Frequently Asked Questions

  • What are the long-term side effects of Trileptal?

    There are no known risks connected to the long-term use of Trileptal. However, some of the short-term side effects (including rash, changes in blood sodium levels, and suicidal thoughts) can persist or worsen. If you notice any of these symptoms, talk to your healthcare provider. They may recommend lowering your dose, stopping the medication, or switching to a different medication.

  • How long do Trileptal side effects last?

    The side effects associated with Trileptal are usually temporary and often begin to subside as you develop a tolerance to the medication. If side effects continue or are severe, talk to your healthcare provider. They may lower your dosage to help alleviate side effects or make them easier to cope with.

  • How can you lessen Trileptal side effects?

    To lessen the side effects of Trileptal, it is helpful to take the lowest possible dose to obtain relief from symptoms. Work with your healthcare provider to monitor your symptoms and adjust the dosage of your medication as necessary to find the right balance.

  • What are the side effects when you stop taking Trileptal?

    You should not stop taking your medication unless directed by your health provider. Abruptly halting Trileptal can result in withdrawal symptoms such as insomnia and the return of bipolar symptoms or seizures. Instead, work with your provider to gradually taper your dose to reduce the risk of seizures or mood symptoms.

7 Sources
Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. Grunze A, Amann BL, Grunze H. Efficacy of carbamazepine and its derivatives in the treatment of bipolar disorder. Medicina. 2021;57(5):433. doi:10.3390/medicina57050433

  3. Vasudev A, Macritchie K, Vasudev K, Watson S, Geddes J, Young AH. Oxcarbazepine for acute affective episodes in bipolar disorder. Cochrane Database Syst Rev. 2011;(12):CD004857. doi:10.1002/14651858.CD004857.pub2

  4. Čiauškaitė J, Gelžinienė G, Jurkevičienė G. Oxcarbazepine and hyponatremia. Medicina. 2022;58(5):559. doi:10.3390/medicina58050559

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Additional Reading

By Marcia Purse
Marcia Purse is a mental health writer and bipolar disorder advocate who brings strong research skills and personal experiences to her writing.