10 Carbamazepine Side Effects You Should Know About

Carbamazepine (Tegretol, Equetro) is a medication that treats seizure disorders and a type of nerve pain called trigeminal neuralgia. It’s also prescribed for bipolar disorder. Carbamazepine is available as a tablet in immediate-release (IR) and extended-release (ER) forms. It’s also available as an oral liquid, chewable tablet, and ER oral capsule.

Carbamazepine works well for these conditions, but it can cause several side effects. Some of the common side effects — such as dizziness or drowsiness — can be managed at home. Others, such as blood cell problems or severe skin reactions, are rare but serious.

Good to know: All versions of carbamazepine list the same side effects in their labeling. Studies suggest that some people may tolerate ER forms better than IR forms. However, the side effects discussed here are possible with all forms of carbamazepine.

Carbamazepine side effects at a glance

Below, we’ve listed both common and rare but serious carbamazepine side effects. Common side effects are typically mild and more noticeable when you first start taking it. And they should improve after the first few weeks of treatment.

Common or mild carbamazepine side effects include:

• Dizziness

• Drowsiness

• Nausea

• Vomiting

• Constipation

• Difficulty walking or keeping balance

• Dry mouth

• Weakness

• Rash

• Blurry vision

• Double vision

• Speech problems

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Rare but serious carbamazepine side effects include:

• Low blood sodium levels

• Suicidal thoughts

• Withdrawal seizures if you suddenly stop carbamazepine

• Allergic reactions

• Liver problems

• Raised eye pressure

• Hallucinations

• Heart block (a problem with your heart’s natural electrical activity)

• Neuroleptic malignant syndrome

• Birth defects

This medication also has a few boxed warnings. This is the FDA’s strictest warning for medications. While rare, these side effects can be life-threatening. Carbamazepine has the following boxed warnings:

• Severe skin reactions

• Blood cell problems

These aren’t the only possible carbamazepine side effects. Contact your prescriber about unusual or bothersome side effects — even if they’re not listed here.

Now, let’s take a closer look at 10 carbamazepine side effects and some suggestions for how to manage them.

1. Dizziness

Dizziness is a common carbamazepine side effect. It may be more noticeable when you first start the medication or after raising your dose.

EXPERT PICKS: WHAT TO READ NEXT

• Compare options: Carbamazepine (Tegretol, Equetro) is one of several anti-seizure medications available.

• Avoiding interactions: Certain medications and foods interact with carbamazepine, raising your risk of side effects.

• Bipolar disorder treatments: Read about which medications, including carbamazepine, are typically prescribed to manage bipolar disorder.

You might have a higher risk of dizziness if you also take other medications that cause dizziness. Examples include other seizure medications, antidepressants, and blood pressure medications. You should avoid drinking alcohol while taking carbamazepine. This can also worsen dizziness.

If you do experience dizziness while taking carbamazepine, these tips can help manage it:

• Find a place to sit or lie down until dizziness passes.

• Take your time when changing positions, such as going from sitting to standing.

• Drink plenty of water or other fluids to stay hydrated.

• Eat a small snack.

If dizziness doesn’t get better or go away, talk to your prescriber about whether you need a lower dose of carbamazepine. Or they may recommend a different medication altogether.

2. Drowsiness

Drowsiness is another common carbamazepine side effect. Like dizziness, it’s more common when you first start it or after raising your dose. It’s also more likely to happen if you drink alcohol or take other medications that cause drowsiness. Examples include muscle relaxers and certain antihistamines.

You should avoid driving or performing other tasks requiring alertness until you know how carbamazepine makes you feel.

If you feel drowsy while taking carbamazepine, there are some ways to help limit or manage it:

• If you take carbamazepine once a day, ask your prescriber about taking your dose at bedtime.

• Keep a consistent sleep schedule, even on weekends.

• Exercise or find ways to include more movement in your routine.

• Add energy-boosting foods, such as blueberries and bananas, to your diet.

If drowsiness doesn’t improve, let your prescriber know. They may recommend a lower carbamazepine dosage. Or they may recommend a different medication altogether. But don’t make any changes to your medication without talking to a healthcare professional first.

3. Gastrointestinal side effects

Some people report gastrointestinal (GI) side effects from carbamazepine. They’re more likely with higher doses and include:

• Nausea

• Vomiting

• Diarrhea

• Abdominal pain

• Constipation

Taking carbamazepine with food can help prevent nausea. If you do feel nauseated, try eating bland foods, such as toast or applesauce, for a few days. Slowly adding fiber to your diet can help ease constipation. And staying well hydrated can help prevent dehydration if you experience vomiting or diarrhea.

If you have GI side effects from carbamazepine, talk to your prescriber or pharmacist. They may recommend over-the-counter (OTC) medications to help with constipation, diarrhea, and nausea. If your GI side effects are severe or persistent, tell your prescriber. This isn’t typical with carbamazepine.

4. Blurred vision

Blurry vision is another common carbamazepine side effect. But it’s not the only possible vision-related side effect that can happen. Carbamazepine can also cause double vision and uncontrollable eye movements. And in rare cases, it can raise the pressure inside your eye. These side effects sometimes happen if your carbamazepine dosage is too high.

If you experience any vision or eye-related side effects with carbamazepine, tell your prescriber. And don’t drive if you’re experiencing these issues. Sometimes, blurry or double vision is temporary and gets better with time. But it can also point to more serious eye complications. Your prescriber may want to check your eyes or adjust your carbamazepine dosage.

5. Difficulty walking or keeping balance

Difficulty walking or keeping balance is also possible when taking carbamazepine. These could go along with some other carbamazepine side effects, such as dizziness or blurry vision. And issues balancing can be a possible long-term carbamazepine side effect.

Balance problems can lead to falls. And while this could be harmful for anyone, it may be particularly dangerous if you’re age 65 or over. If you notice this carbamazepine side effect, talk with your prescriber. They may recommend a change to your carbamazepine dosage.

6. Low sodium levels

Carbamazepine may cause low sodium levels (hyponatremia). This is probably because it can cause a condition where you retain too much water (called antidiuretic hormone secretion, or SIADH).

Low sodium levels are more likely to happen if you take high doses of carbamazepine. But it may also be more likely if you:

• Are female

• Are over 40 years old

• Already have low sodium levels

• Have certain medical conditions, such as hypothyroidism, heart failure, or a mental health condition

• Take other medications that can lower sodium levels, such as diuretics (“water pills”)

Hyponatremia from carbamazepine is rare, but it can be dangerous. Mild symptoms include nausea, headache, and tiredness. More serious symptoms include confusion, seizures, and coma.

Your prescriber may check your sodium levels from time to time while you’re taking carbamazepine. If you experience symptoms of hyponatremia at any point, contact your prescriber right away.

7. Suicidal thoughts or behavior

Anti-seizure medications like carbamazepine can increase the risk of suicidal thoughts or behavior. Although this is rare, it can happen at any time during treatment.

If you have any unusual mood or behavior changes, let your prescriber know or seek emergency help. This includes feeling more depressed after starting carbamazepine.

If you or someone you know is having thoughts of suicide, you’re not alone, and help is available. Call the National Suicide Prevention Lifeline at 988, or text HOME to 741-741 to reach the Crisis Text Line.

8. Blood cell problems

Carbamazepine has a boxed warning for low levels of red blood cells, platelets, or white blood cells. Rarely, carbamazepine can cause a severe drop in blood cell levels. This is called aplastic anemia. Symptoms may include tiredness, easy bruising and bleeding, or infections that last a long time.

Carbamazepine can also cause severely low neutrophils (a type of white blood cell). This is called agranulocytosis. Symptoms may include fever, oral infections, and difficulty swallowing.

Your prescriber should check your blood cell levels before and during carbamazepine treatment. If you start to have symptoms of a blood cell problem, contact your prescriber right away. If your blood cell counts drop significantly or you have serious symptoms, you may need to stop carbamazepine.

9. Serious skin reactions

Serious skin reactions, such as drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome, may also occur while taking carbamazepine. This is another boxed warning included in carbamazepine’s labeling.

These reactions can happen at any point during carbamazepine treatment. But they’re most likely during the first few months. These skin reactions can happen to anyone, but they’re more common in people who carry specific genes. Your prescriber may suggest getting a blood test to screen for these genes before starting carbamazepine.

Symptoms of serious skin reactions may include:

• A high fever

• A sudden rash that covers a large area of the body and may lead to blisters that peel

• Difficulty swallowing

• Trouble breathing

• Facial swelling

If you notice any of these symptoms, seek emergency care. These types of skin reactions can be life-threatening.

10. Withdrawal seizures and symptoms

Abruptly stopping carbamazepine can cause withdrawal seizures. You may also have other withdrawal symptoms if you stop taking carbamazepine, including trouble sleeping, low mood, and headache.

In some cases, carbamazepine may cause serious side effects that require you to stop taking it immediately. But don’t stop carbamazepine without specific instructions from your prescriber. If you’re not experiencing a serious carbamazepine side effect, your prescriber will likely recommend lowering your dose slowly. Don’t lower your dose faster than recommended. And don’t stop taking carbamazepine on your own.

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Written by:

Nicole E. Cieri-Hutcherson, PharmD, BCPS, NCMP

Nicole E. Cieri-Hutcherson, PharmD, BCPS, NCMP, has over a decade of experience as a pharmacist, professor, and researcher. She was a full-time clinical professor in the pharmacy practice department at D’Youville School of Pharmacy before subsequently joining the faculty of the pharmacy practice department at the University at Buffalo School of Pharmacy and Pharmaceutical Sciences.

Edited by:

Christina Aungst, PharmD

Christina Aungst, PharmD, is a pharmacy editor for GoodRx. She began writing for GoodRx Health in 2019, transitioning from freelance writer to editor in 2021.

Reviewed by:

Stacia Woodcock, PharmD

Stacia Woodcock, PharmD, is a pharmacy editor for GoodRx. She earned her Doctor of Pharmacy degree from the University of Kentucky and is licensed in New York and Massachusetts.

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