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Carbamazepine

(car-buh-maz-uh-peen)

Trade/other name(s): Carbatrol, Epitrol, Equetro, Tegretol, Tegretol XR, Teril

Why would this drug be used?

Carbamazepine is used to help relieve pain. It belongs to a general class of drugs called anticonvulsants. It is given along with other pain medicines to help control neuropathic pain (numbness, tingling, burning, shooting, or electric-shock-like pain). It is also used for preventing seizures and other purposes.

How does this drug work?

Exactly how carbamazepine works is unknown. It appears to block the activity of certain nerves.

Before taking this medicine

Tell your doctor…

  • If you are allergic to anything, including medicines, dyes, additives, or foods.
  • If you have any medical conditions such as kidney disease, liver disease (including hepatitis), heart disease (including electrical conduction problems such as heart block or heart rhythm problems), or congestive heart failure. These conditions may require that your medicine dose, regimen, or timing be changed.
  • If you have porphyria or if you have had problems with your bone marrow (anemia, low white blood cell count or platelet count), especially if it happened when you took anti-seizure medicines. Your risk of serious complications is higher.
  • If you have or have ever had increased pressure in your eye, or if you have glaucoma.
  • If you have taken monoamine oxidase inhibitors (MAOIs) such as isocarboxazid, phenelzine, selegiline, or tranylcypromine within the past 2 weeks. Carbamazepine may cause serious side effects if taken with these drugs (see “Interactions with other drugs”).
  • If you or a relative have had an allergy or organ sensitivity (for example, severe skin rash or major liver problem) with any anti-seizure drug. This may suggest an increased risk of having a similar problem when taking carbamazepine.
  • If you have ever had problems with a tricyclic antidepressant (TCA) such as amitriptyline (Elavil), nortriptyline (Pamelor), desipramine (Norpramin), doxepin (Sinequan), or others.
  • If you have had mental health problems in the past. Certain types of problems may be worsened by carbamazepine.
  • If you have trouble passing urine. Carbamazepine may make this worse.
  • If you are pregnant, trying to get pregnant, or if there is any chance of pregnancy. Carbamazepine has not been formally studied in pregnant women, but some problems such as low birth weight, small head size, spina bifida, and other problems have been reported in the babies of women who took it during pregnancy. There may be an increased risk of harm to the fetus if a woman takes this drug during pregnancy.
  • If you are breast-feeding. The drug passes into breast milk and may harm the baby.
  • About any other prescription or over-the-counter medicines you are taking, including vitamins and herbs. In fact, keeping a written list of each of these medicines (including the doses of each and when you take them) with you in case of emergency may help prevent complications if you get sick.

Interactions with other drugs

The amount of time carbamazepine stays in the body is affected by many drugs. And, it can affect how long other drugs stay in the body as well. It is very important for your doctor, nurse, and pharmacist to know about all of the drugs and supplements you are taking, as well as when you start or stop any drug (including carbamazepine), because the dose of one or more of the drugs may need to be changed.

The following medicines may increase the levels of carbamazepine in your body and raise the risk of side effects. If you need to take any of them along with carbamazepine, your doctor may lower your dose of carbamazepine:

  • Stomach acid reducer: cimetidine
  • Endometriosis and fibrocystic breast treatment: danazol
  • Blood pressure medicines (calcium channel blockers): diltiazem, verapamil
  • Antibiotics of the macrolide family, such as erythromycin and clarithromycin
  • Antidepressants and mental health medicines: fluoxetine, fluvoxamine
  • Antihistamine: loratidine
  • Anti-tuberculosis medicine: isoniazid
  • Vitamin B3: niacinamide, nicotinamide
  • Antifungal drugs: ketoconazole, fluconazole, itraconazole
  • Glaucoma pills: acetazolamide
  • Anti-nausea medicine: aprepitant
  • HIV drugs: protease inhibitors, such as ritonavir and indinavir
  • Anti-seizure drugs: valproate

Some medicines will cause the body to get rid of carbamazepine faster and decrease its effectiveness, such as:

  • Anti-seizure drugs: phenobarbital, phenytoin, primidone, methsuximide, felbamate
  • Anti-cancer drugs: cisplatin, doxorubicin
  • Anti-tuberculosis drug: rifampin
  • Breathing drug: theophylline

In some cases, carbamazepine also lowers the effectiveness of these drugs at the same time the drug lowers carbamazepine’s effectiveness (see below).

Carbamazepine makes these drugs stay longer in the body. This can increase the risk of problems and toxic side effects:

  • Anti-seizure drugs: phenytoin, primidone
  • Antidepressant: clomipramine

Carbamazepine can make these drugs to be less effective by causing the body to get rid of them faster:

  • Tranquilizers or sedatives: alprazolam, clonazepam, diazepam, lorazepam, midazolam, oxcarbazepine, triazolam
  • Pain medicines: acetaminophen, methadone, tramadol
  • Antidepressants such as imipramine, amitriptyline, desipramine, nortriptyline, and others of the tricyclic type; also bupropion, citalopram, mirtazapine, and trazodone
  • Anti-inflammatory medicines: corticosteroids (such as prednisone, dexamethasone, or other cortisone-like drugs)
  • Antipsychotics: clozapine, haloperidol, quetiapine, olanzapine, risperidone, ziprasidone, aripiprazole
  • Calcium channel blocker type blood pressure medicines, for example, felodipine, and others
  • Anti-seizure drugs: ethosuximide, felbamate, lamotrigine, methsuximide, phensuximide, phenytoin, tiagabine, topiramate, valproate, zonisamide
  • Blood thinners: dicumarol, warfarin
  • Thyroid medicine: levothyroxine
  • Birth control pills (oral contraceptives), other hormonal contraceptives such as implants and ring, and female hormones
  • Antibiotic, anti-fungal, and anti-parasite drugs: doxycycline, itraconazole, ketoconazole, and praziquantil
  • Immunosuppressant (to prevent organ rejection): cyclosporine
  • Anti-HIV drugs: ritonavir, indinavir, saquinavir, amprenavir, lopinavir, darunavir, nelfinavir, delavirdine, and possibly others
  • Breathing medicine: theophylline

The antidepressant nefazodone should not be taken while you are taking carbamazepine.

Cyclophosphamide, a cancer treatment drug, may have more toxic effects if given while a person is taking carbamazepine. Lapatinib, another cancer treatment drug, doesn’t work as well if the person is taking carbamazepine. Your doctor may change your doses of these drugs.

Carbamazepine can increase the loss of sodium from the body if you’re taking a blood pressure medicine that makes you put out more urine (diuretics like furosemide or hydrochlorothiazide). This can cause vomiting, headache, fatigue, weakness, confusion, and even seizures or coma.

Medicines that slow down the brain or nervous system, such as opioid pain relievers, tranquilizers, sedatives, sleeping pills, antidepressants, muscle relaxers, antihistamines, phenothiazines, anesthetic medicines, and alcohol can cause worse side effects if taken with carbamazepine.

Antidepressants called monoamine oxidase inhibitors (MAOIs), such as isocarboxazid, phenelzine, procarbazine, selegiline, and tranylcypromine, may cause high body temperature, high blood pressure, and seizures if carbamazepine is given within 2 weeks of the last MAOI dose.

Lithium can have a higher risk of neurological (brain or nervous system) side effects if taken with carbamazepine. Anti-malarial drugs (such as chloroquine and mefloquine) may cause carbamazepine to have less of its desired effect.

If you take the liquid form of the drug, don’t take it at the same time as other liquid medicines.

Carbamazepine might interact with other drugs as well. Check with your doctor, nurse, or pharmacist about whether other medicines, vitamins, herbs, and supplements can cause problems with this medicine.

Interactions with foods

Grapefruit, grapefruit juice, and grapefruit extract can raise the level of this drug in your body. This can worsen any bad effects the drug may have on you and may increase its action in harmful ways.

Alcohol may have more potent effects on the nervous system while taking this drug. Its use should be minimized or avoided while taking this drug.

Check with your doctor, nurse, or pharmacist about whether other foods may be a problem.

Tell all the doctors, dentists, nurses, and pharmacists you visit that you are taking this drug.

How is this drug taken or given?

This drug is usually started at a low dose and gradually increased. This helps to lower your risk of side effects. Carbamazepine comes in tablets, capsules, liquid, extended release beads, and extended release capsules. Your dose will depend on how much is needed to control your pain.

Time-release tablets or capsules must never be chewed, broken, split, or dissolved. The full 24 hour dose can be absorbed all at once. The coatings of the time release pills are not absorbed and may be seen in the stool.

Some types of capsules have small time-release beads that dissolve slowly in the body. The capsules can be swallowed whole, or they can be carefully opened and the beads sprinkled on a spoonful of cold applesauce. The applesauce must be swallowed right away, without chewing. Rinse your mouth with water 2 or 3 times afterward in order to wash down and swallow any remaining beads without chewing them. If the applesauce is not eaten right away, flush it down the toilet. Do not save it for later, because its moisture will dissolve the beads.

Don’t take the liquid form of this medicine at the same time that you take other liquid medicines.

Take this drug exactly as directed by your doctor. If you do not understand the instructions, ask your doctor or nurse to explain them to you. Keep the medicine in a tightly closed container away from heat and moisture and out of the reach of children, pets, or others. Keep the liquid forms of this medicine from freezing. Medicine that will not be used should be flushed down the toilet as soon as possible.

Precautions

This medicine can cause drowsiness, clumsiness, and trouble walking. Do not drive, operate machinery, or perform other activities that require mental alertness and physical coordination until you know how you react to this medicine.

Be careful getting up, changing position, or walking. Get up slowly and hold onto something or someone to keep you steady. If you feel lightheaded or dizzy, it may help to lie down. Have a responsible adult with you until you have adjusted to the medicine.

Since carbamazepine affects the central nervous system, it is important not to take other drugs or substances that slow down the brain or nervous system such as alcohol, sedatives, muscle relaxers, and sleeping medicines unless your doctor tells you it is OK to do so.

If you are sensitive to tricyclic antidepressant medicines or to other anti-seizure medicines, you may be at greater risk of reacting to carbamazepine.

As with other anti-seizure medicines, this drug may rarely raise the risk of suicidal thoughts and actions. If you notice any strange or unusual thoughts or behavior, such as irritability, sleep problems, aggressiveness, restlessness, panic attacks, or thoughts of suicide while on this medicine, call your doctor. Tell family members, loved ones and caregivers that you’re taking this drug, so that they can help you notice behavior changes.

Your doctor may check your blood counts and test your liver and kidney function before you start taking carbamazepine. Rarely, it can cause low white blood cell counts with risk of infection, low platelet counts with an increased risk of bleeding, or low red blood cell counts with anemia and possible dizziness and fatigue after you have taken it for some weeks. Severe reactions can lead to all blood counts becoming low, a condition called aplastic anemia. Sometimes just the white blood cell count becomes very low, which is called agranulocytosis. Either of these conditions can lead to death. Report signs of infection (like sore throat, fever, chills), unusual bruising or bleeding, mouth sores, dizziness, weakness, or fatigue to your doctor, as these could mean that your blood counts are getting low.

Sometimes carbamazepine can cause a severe rash, usually in the first few months you take it. In some cases, the rash can cause skin all over the body to blister and peel. If untreated, it can quickly progress into a life-threatening problem. Call your doctor right away if you notice any rash, fever, swelling in the face, flu-like symptoms, swollen glands, or sores in the mouth, nose, or throat. Another type of rash can occur as a part of an allergic reaction. This can cause skin welts, trouble breathing, or swelling of the face, mouth, or throat. Get emergency help right away if you notice these symptoms.

People with Native American, Southern Indian, Asian, African-American, and Arabic ancestry are more likely to have a certain genetic variant that makes severe skin reactions more likely. Your doctor may test you for this genetic variant before you start this drug.

Call your doctor if you have trouble walking or talking, or if you notice confusion while on carbamazepine.

Carbamazepine can cause you to sunburn easily. Protect your skin from sun, especially between 10 a.m. and 4 p.m., and avoid tanning beds.

If you are using birth control pills, hormone patches, or implants while on carbamazepine, they may not work as well. Talk to your doctor if you notice changes in your menstrual periods, such as breakthrough bleeding (bleeding between periods). Back-up methods of birth control are recommended while on carbamazepine.

Call your doctor if you plan to start or stop any medicine while on carbamazepine. Your dose may need to be adjusted due to possible interactions.

If you are using carbamazepine for chronic (long term) cancer pain, talk with your doctor or nurse about taking your pain medicines on a regular schedule to keep it from worsening. If you wait until the pain is bad, it takes more medicine to get it under control. If pain comes back between doses, talk to your cancer team about changing your medicine or adding an extra one for “breakthrough” pain. Most cancer pain can be controlled. Keep your doctor or nurse informed about how well your pain medicines are working and any side effects you are having. Your cancer team may need to adjust your medicines several times before they find the medicines that work best for you.

Don’t stop taking carbamazepine suddenly if you are taking it to prevent seizures, since seizures may occur in some cases. Your doctor will talk with you about tapering down gradually over a few weeks.

Your doctor may check your eyes before you start this drug, and check them regularly while you take it. Carbamazepine can cause changes in the way the eyes move, and it can cause blurred or double vision in some people.

Carbamazepine may interfere with pregnancy tests and thyroid tests.

Possible side effects

You will probably not have most of the following side effects, but if you have any talk to your doctor or nurse. They can help you understand the side effects and cope with them.

Common

  • Unsteadiness*
  • Dizziness*
  • Drowsiness*
  • Nausea
  • Vomiting

Less common

  • Abnormal lab tests of the liver
  • Liver damage
  • Blurred or double vision
  • Increased sensitivity to sun (easy to sunburn)

Rare

  • Itching*
  • Skin welts*
  • Trouble urinating
  • Fever, chills
  • Low white blood cell counts with higher risk of infection*
  • Low platelet counts with an increased risk of bleeding*
  • Low red blood cell counts (anemia) with dizziness, shortness of breath, weakness
  • Low sodium levels in the body, with vomiting, headache, weakness, seizures
  • Confusion*
  • Agitation
  • Diarrhea
  • Aching muscles and joints
  • Serious skin rash with flu-like symptoms, fever, swollen glands*
  • Glaucoma
  • Suicidal thoughts or actions*
  • Abnormal heart rhythms such as heart block
  • Death from severe skin reaction or low blood counts (aplastic anemia and agranulocytosis)

*See “Precautions” section for more detailed information.

There are other side effects not listed above that can also occur in some patients. Tell your doctor or nurse if you develop these or any other problems.

FDA approval

Yes – first approved before 1984 (FDA cannot verify dates of drugs approved before 1984).

Disclaimer: This information does not cover all possible uses, actions, precautions, side effects, or interactions. It is not intended as medical advice, and should not be relied upon as a substitute for talking with your doctor, who is familiar with your medical needs.


Last Medical Review: 04/30/2013
Last Revised: 04/30/2013