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What is carbamazepine?

Carbamazepine (kaar·buh·ma·zuh·peen) is a medication used in the treatment of seizures, nerve pain, and bipolar disorder.

Doctors may also prescribe carbamazepine off-label to prevent migraines. However, it is not FDA approved for this purpose. The term “off-label” refers to the therapeutic use of a drug to treat a condition or disease other than what it was originally made or approved to treat.

Carbamazepine belongs to a class of drugs called anticonvulsants

Carbamazepine is the generic drug name for the brands Tegretol and Carbatrol (and several other brands).

What is carbamazepine used to treat?

Carbamazepine is an anticonvulsant medication that decreases abnormal bursts of electrical activity in the brain, thereby preventing or reducing seizures. Carbamazepine treats various seizure disorders, including partial and tonic-clonic (grand mal) seizures.

Extended-release capsules are also used in the treatment of some psychiatric disorders, such as mania and bipolar disorders. 

Carbamazepine can also prevent migraine headaches and relieve pain in people with trigeminal neuralgia (a chronic pain disorder that affects nerves in the face) and can be used as part of the treatment of peripheral neuropathy. 

Carbamazepine is sometimes prescribed as a mood stabilizer for those with bipolar disorder. Carbamazepine may also be suitable for treating other conditions as determined by your doctor.

How do you take carbamazepine?

Carbamazepine is available as a tablet, chewable tablet, suspension, extended-release tablet, or capsule.

Be sure to swallow capsules or non-chewable tablets whole. Do not chew or crush them. If using a suspension, shake it well before drinking.

Depending on the condition being treated and your age, your prescribing doctor will determine the appropriate dosage and schedule for taking carbamazepine. 

Regular tablets, suspensions, and capsules are often prescribed 2–4 times a day with food. Extended-release formulas are generally taken twice daily. 

Dosage for a child under six years old is based on the child’s body weight. 

Typically, doctors will start you on the lowest dosage of carbamazepine possible, such as 100 or 200mg daily. Depending on your response, the dosage may be increased.

Seeing results of carbamazepine

Whether carbamazepine is being used to treat seizures, for the treatment of nerve pain, or to treat a mood disorder (such as bipolar disorder) results will typically start to take effect within 1–4 weeks. Variability of responses to carbamazepine depends on the severity of the condition being treated, as well as the individual’s baseline health and functioning. If you are taking carbamazepine to treat a mood disorder, staying on it for a 6-month minimum will usually be recommended¹ to achieve its full mood-stabilizing effect. Remember that even if you are feeling well, you should not stop taking carbamazepine without direction from your prescribing doctor. 

Stopping carbamazepine suddenly could have serious unwanted effects, like the return of symptoms or seizures.

Potential side effects of carbamazepine

Warning: Serious or fatal side effects

While uncommon, it is possible to experience serious and even fatal reactions when taking carbamazepine. Such reactions are different from other forms of allergic reactions to medication.

Toxic epidermal necrolysis and Stevens Johnson syndrome

Those who possess the HLA-B*1502 gene variant have a greater risk² of developing toxic epidermal necrolysis (TEN) and Stevens-Johnson syndrome (SJS) when taking carbamazepine. These reactions cause severe skin and organ damage and could be fatal. Research indicates that within certain population demographics, the risk of developing these severe side effects is as much as ten times higher compared to other groups. The HLA-B*1502 genetic variant is found mainly in those with ancestry broadly spanning Asia.

Genetic testing can be used to screen for HLA-B*1502 before your doctor prescribes carbamazepine treatment. If you have this gene variant, you should not take carbamazepine (unless your doctor determines that the potential benefits outweigh the risks).

Drug-induced aplastic anemia

Taking carbamazepine is associated with an increased risk of developing a severe and sometimes fatal condition called drug-induced aplastic anemia, which is a type of blood disorder that affects bone marrow. A 2006 study³ found that carbamazepine is associated with nine times higher increased risk of aplastic anemia.

Liver damage

Clinical research from the National Institute of Diabetes and Digestive and Kidney Diseases, describes carbamazepine as a well-established cause of severe and even fatal liver injury⁴ (hepatotoxicity). Carbamazepine toxicity may be reversible under medical supervision.

Suicidal ideation

Anti-epileptic drugs (AEDs) are controversial, especially since the Food and Drug Administration (FDA) issued a warning⁵ to healthcare professionals about them in 2008. The warning indicated that treatment with any AED correlated with an increased risk of suicidal ideation, suicide attempt, and completed suicide. This was understandably concerning, especially for those with epilepsy. 

However, the methodology behind the studies is criticized⁶ for being biased. Similarly, the way that specialists in the initial studies monitored for suicidal thoughts and behaviors varied⁵. Some attempts to duplicate initial research findings found no statistical significance between suicide risk and AEDs.  A more recent review⁶ of 13 studies has reported that carbamazepine was found to correlate with the highest suicide attempt rates compared to valproate and lithium. The same review also found that individuals taking carbamazepine had the lowest suicide death rate compared to those taking valproate or lithium. However, it was found that both suicide attempts and suicide completion rates were still lower while taking carbamazepine than with no treatment at all.

If you take carbamazepine or any AED, it is essential to inform your doctor if you have any history of mental illness or episodes of suicidal ideation.

If your doctor assesses your health profile and finds that the potential benefits of taking carbamazepine outweigh the risks, keep track of your daily behavior and mood while taking it.

Discuss risk factors and warning signs with your doctor before starting carbamazepine, and inform them immediately if you notice any changes in your mood and behavior.

If you experience any of these symptoms, notify your doctor, call 911 or visit the nearest emergency room. 

Additional side effects associated with taking carbamazepine include (but may not be limited to):

  • Blurry vision

  • Changes in a heartbeat (fast, slow, or pounding)

  • Difficulty swallowing

  • Shallow or difficulty breathing

  • Swelling 

  • Rash

  • Muscle and joint pain

  • Skin or eye yellowing (jaundice)

  • Drowsiness

  • Dizziness

  • Nausea or vomiting

  • Loss of coordination

  • Changes in liver enzymes or lipid profiles

  • Lowered vitamin D levels

  • Increased risk of osteoporosis or osteopenia

Never stop your medication abruptly or adjust your dosage of carbamazepine without consulting your doctor.

Long-term use of carbamazepine

It is important to note that some of the side effects listed above may not happen immediately and could occur or worsen with long-term medication use. 

You must follow up with your doctor for routine blood work and seek medical attention immediately if you notice any skin rashes or negative changes in mood or behavior while taking carbamazepine.

Missed doses of carbamazepine

If you miss a dose of carbamazepine, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and take your next dose at the regular time. 

Do not take two doses of carbamazepine at the same time (or even close to each other) as this could result in overdose. 

Carbamazepine overdoses

Symptoms of toxic levels of carbamazepine or overdose may include:

  • Loss of consciousness

  • Convulsions

  • Vomiting

  • Drowsiness

  • Lack of coordination

  • Slurred speech

  • Involuntary and repetitive eye movements (nystagmus)

  • Muscle spasms

  • Hallucinations

  • Slow or shallow breathing

  • Blurry vision

  • Muscle twitches

  • Change in heart rate

  • Peeling, blistering skin

  • Fever

  • Raw patches of skin

  • Burning eyes

  • A spreading rash with a purple or red hue

Overdose symptoms appear after 1–3 hours from the time the drug was taken, nervous and muscular symptoms often are the first and most prominent to notice. Seek immediate medical attention or call 911 if a carbamazepine overdose is suspected.

What to discuss with your doctor before taking carbamazepine

Before taking carbamazepine, it is essential to discuss the potential risks and benefits of the medication with your doctor. Some of the things you should consult with your doctor include:

  • Your complete medical history, including any seizure disorders, suicide ideation, history of bone marrow disorders, depression, or any other psychiatric or mental health issues.Any other medications you are taking, including over-the-counter medications and supplements.

  • Your current health status, including any allergies or other conditions you have.

  • Dietary habits and foods to avoid while taking carbamazepine.

  • Whether or not you consume alcohol, how much, and how frequently.

  • Whether you are considering becoming pregnant, pregnant, or breastfeeding (carbamazepine can pass into breast milk and may harm a nursing baby).

After you have discussed the potential risks and benefits of carbamazepine with your doctor, you can then make an informed decision about whether or not this medication is right for you.

If you do decide to take carbamazepine, be sure to follow your doctor's instructions carefully and promptly report any side effects that you may experience.

With proper treatment, carbamazepine can help control seizure disorders, manage nerve pain, and improve the quality of life for patients with bipolar disorder.

Stopping carbamazepine

Do not stop taking carbamazepine without talking to your doctor first. Stopping carbamazepine suddenly can cause serious side effects.

If you are considering stopping carbamazepine, talk to your doctor about the best way to do it. You may need monitoring to slowly reduce the dose of carbamazepine before you stop taking it completely (medication tapering).

Carbamazepine and pregnancy

If you are pregnant or thinking of becoming pregnant, it’s important to know that carbamazepine can be harmful to your baby. 

Carbamazepine can cause congenital abnormalities of various systems⁷, including heart defects, cleft lip and palate, and problems with the brain and spinal cord, in addition to developmental issues.

It’s important to talk to your doctor about the risks of taking carbamazepine during pregnancy, as they will weigh the benefits of the therapy against its risk. 

If you are pregnant and taking carbamazepine, you should be monitored closely by your doctor. You may also be advised to take a higher dose of folic acid during your pregnancy.

Taking carbamazepine can cause inaccurate at-home pregnancy test results. Speak to your doctor if you believe you might be pregnant. 

Interactions with other drugs

Carbamazepine can interact with other drugs and may elevate circulating levels of these drugs (or carbamazepine) to dangerous levels. Discuss all prescribed and non-prescribed drugs with your doctor before taking carbamazepine. The most common and or/significant interactions are with (but may not be limited to):

  • Other anticonvulsants

  • Antispasmodics

  • Antacids, reflux medication, or stomach ulcer medication

  • Blood thinners

  • Oral contraceptives (birth control) 

  • Sedatives

  • Psychiatric medications, including certain antidepressants

  • Antivirals

  • Some antibiotics including macrolides

  • Glaucoma medication

  • Tuberculosis medication

  • Antifungals

  • Migraine medication

  • Blood pressure medication

  • Androgenic hormones (such as those used to treat endometriosis and cystic fibrosis)

  • Opioid painkillers

  • Corticosteroids

  • Immunosuppressants

  • Some bronchodilators for asthma, COPD, or emphysema

  • Chemotherapy drugs

  • Heart medications

If you are taking or planning to take any of these drugs, talk to your doctor before starting carbamazepine. They may need to adjust your dosage, monitor you closely for side effects, or suggest alternative medications with a lower risk of interaction with carbamazepine.

Can alcohol be consumed while taking carbamazepine?

Do not drink alcohol while taking carbamazepine, because it can dangerously increase carbamazepine’s sedative properties. 

Allergy information

Symptoms of an allergic reaction² to carbamazepine include:

  • Rash

  • Itching

  • Swelling of the lips, tongue, and airways

  • Shortness of breath

  • Wheezing

  • Coughing

  • Hives

If you experience symptoms of a severe allergic reaction to carbamazepine, seek immediate medical attention or call 911.

Approval history

Epilepsy treatment

In 1968⁸ carbamazepine was approved by the United States Food and Drug Administration (US FDA) for the treatment of epilepsy. In 1996⁸ an extended-release formulation was approved.

Trigeminal neuralgia

In 1968⁸ carbamazepine was approved by the US FDA for treatment of trigeminal neuralgia. In 1996⁸ an extended-release formulation was approved.

Bipolar disorder

In 2004⁸ extended-release carbamazepine was approved by the US FDA to treat acute manic episodes associated with bipolar disorder.

Tips and advice for taking carbamazepine

Here are some tips to help you take carbamazepine safely and effectively:

  • Do not drink alcohol while taking carbamazepine.

  • Take carbamazepine with food or milk to lessen stomach upset.

  • Swallow the extended-release tablets whole. Do not crush, chew, or break them.

  • Carbamazepine may make your skin photosensitive (sensitive to the sun). Wear sunscreen and protective clothing when you are outdoors.

  • Tell your doctor if you plan on becoming pregnant if you are currently pregnant or breastfeeding. Carbamazepine can pass into breast milk and may harm a nursing baby.

  • Carbamazepine may interact with other medications. Tell your doctor about all the drugs and medications you use, including over-the-counter medicines, vitamins, and herbal supplements.

  • Do not stop taking carbamazepine without talking to your doctor. Stopping suddenly can cause serious side effects.

  • Carbamazepine is not a pain reliever and should not be taken for aches, pains, or muscle strains.

If you have any questions about taking carbamazepine, talk to your doctor or pharmacist.

Curious about clinical trials?

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Here at HealthMatch, we’ve done our best to ensure that the information provided in this article is helpful, up to date, and, most importantly, accurate.

However, we can’t replace the one-to-one advice of a qualified medical practitioner or outline all of the possible risks associated with this particular drug and your circumstances.

It is therefore important for you to note that the information contained in this article does not constitute professional medical or healthcare advice, diagnosis or recommendation of treatment and is not intended to, nor should be used to, replace professional medical advice. This article may not always be up to date and is not exhaustive of all of the risks and considerations relevant to this particular drug. In no circumstances should this article be relied upon without independent consideration and confirmation by a qualified medical practitioner.

Your doctor will be able to explain all possible uses, dosages, precautions, interactions with other drugs, and other potential adverse effects, and you should always talk to them about any kind of medication you are taking, thinking about taking or wanting to stop taking.

Curious about clinical trials?

Access the latest treatments and medications. unavailable elsewhere - entirely free of charge. We make it easy to take part.