Carbamazepine Carbamazepine is a dibenzazepine derivative with antiepileptic, neurotropic and psychotropic properties. It is known to block voltage gated sodium channels but may have additional modes of action. It is given orally in two or three divided doses. Treatment should start at 100mg to 200mg daily and be slowly titrated upwards until a satisfactory clinical response is obtained. Some patients may require up to 1600mg daily.

Carbamazepine is a hepatic enzyme inducer and may increase the metabolism of other drugs. It is recommended that a full blood count and serum biochemistry, including liver function tests, are carried out before commencing treatment.

For paroxysmal pain syndromes such as trigeminal neuralgia or painful tonic seizures, carbamazepine and other anticonvulsive drugs are the cornerstone of treatment.

What Drug Acts on Neurogenic Pain?
Neurogenic pain is very difficult to treat. Tricyclic antidepressants, such as amitryptilin are often used in the treatment of this pain. Probably the primary mechanism of tricyclic compounds is to block the reuptake of the neurotransmittor serotonin in the CNS, a substance which enhances pain inhibition in the descending pathways (Thompson et al, 1992). In addition, amitryptilin is a potent sedative drug that may be used as sleeping medication. This compound is not always effective and sometimes anticonvulsive drugs such as clonazepam (Rivotril®) or carbamazepine (Tegretol®) are utilised. As in any chronic pain syndrome in which pharmacotherapy is of limited value, cognitive-behavioral approaches are very effective in providing coping techniques and distraction from pain (Clifford et al, 1984).

Carbamazepine (Tegretol ®) is the drug of choice for trigeminal neuralgia and 70% of patients respond well. Small doses of 50 mg can be effective and it is recommended to start treatment with 50 mg twice a day or three times a day and to increase according to the clinical response. Maintenance doses are individually different, doses between 100 mg and 600 mg being sufficient in most cases. If the increase is too rapid, giddiness may occur, aggravating previously present ataxia. Sometimes the usefulness of carbamazepine may be limited by the effects of sedation and weakness. The drug is known to have haematological and hepatic side effects and initially blood counts and liver function have to be controlled. In cases of intolerance or when Carbamazepine is ineffective Baclofen (Lioresal®) or Phenytoin have been shown to be useful alternatives. For the rare cases not reacting to medication, glycerol injections in the nerves or thermocoagulation can be proposed. This last method leaves a less disturbing numbness in its place.

Tonic Seizures (Spasms)
During tonic spasms, which are not pathognomonic but strongly suggestive of MS, the arm and the leg of the same side of the body contract in a very painful manner which may last many seconds but rarely for minutes (Buchholz & Mumenthalter, 1987). Consciousness is preserved throughout the attacks. These symptoms can occur repeatedly in a day and may be brought about by changes in body position or by hyperventilation. Here again anticonvulsive drugs such as Carbamazepine work effectively.

Brand Names
Some commonly used brand names are:

In the U.S.--

Atretol
Carbatrol
Epitol
Tegretol
Tegretol-XR
In Canada--

Apo-Carbamazepine
Novo-Carbamaz
Nu-Carbamazepine
Taro-Carbamazepine
Taro-Carbamazepine CR
Tegretol
Tegretol Chewtabs
Tegretol CR
Generic name product may be available in the U.S.
 
 

Category
Anticonvulsant
Antidiuretic
Antimanic
Antineuralgic, specific pain syndromes
Antipsychotic
 

Description
Carbamazepine (kar-ba-MAZ-e-peen) is used to control some types of seizures in the treatment of epilepsy. It is also used to relieve pain due to trigeminal neuralgia (tic douloureux). It should not be used for other more common aches or pains.

Carbamazepine may also be used for other conditions as determined by your doctor.

This medicine is available only with your doctor's prescription, in the following dosage forms:

Oral
Oral Suspension (U.S. and Canada)
Tablets (U.S. and Canada)
Chewable tablets (U.S. and Canada)
Extended-release capsules (U.S.)
Extended-release tablets (U.S. and Canada)
 
 

Before Using This Medicine
In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For carbamazepine, the following should be considered:

Allergies--Tell your doctor if you have ever had any unusual or allergic reaction to carbamazepine or to any of the tricyclic antidepressants, such as amitriptyline, amoxapine, clomipramine, desipramine, doxepin, imipramine, nortriptyline, protriptyline, or trimipramine. Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.

Pregnancy--Carbamazepine has not been studied in pregnant women. However, there have been reports of babies having low birth weight, small head size, skull and facial defects, underdeveloped fingernails, and delays in growth when their mothers had taken carbamazepine in high doses during pregnancy. In addition, birth defects have been reported in some babies when the mothers took other medicines for epilepsy during pregnancy. Also, studies in animals have shown that carbamazepine causes birth defects when given in large doses. Therefore, the use of carbamazepine during pregnancy should be discussed with your doctor.

Breast-feeding--Carbamazepine passes into the breast milk, and in some cases the baby may receive enough of it to cause unwanted effects. In animal studies, carbamazepine has affected the growth and appearance of the nursing babies.

Children--Behavior changes are more likely to occur in children.

Older adults--Confusion; restlessness and nervousness; irregular, pounding, or unusually slow heartbeat; and chest pain may be especially likely to occur in elderly patients, who are usually more sensitive than younger adults to the effects of carbamazepine.

Other medicines--Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking carbamazepine, it is especially important that your health care professional know if you are taking any of the following:

Anticoagulants (blood thinners)--The effects of anticoagulants may be decreased; monitoring of blood clotting time may be necessary during and after carbamazepine treatment
Cimetidine (e.g., Tagamet)--Blood levels of carbamazepine may be increased, leading to an increase in serious side effects
Clarithromycin (e.g., Biaxin)--Blood levels of carbamazepine may be increased, increasing the risk of unwanted effects
Corticosteroids (cortisone-like medicine)--The effects of corticosteroids may be decreased
Diltiazem (e.g., Cardizem) or
Erythromycin (e.g., E-Mycin, Erythrocin, Ilosone) or
Propoxyphene (e.g., Darvon) or
Verapamil (e.g., Calan)--Blood levels of carbamazepine may be increased; these medicines should not be used with carbamazepine
Estrogens (female hormones) or
Oral contraceptives (birth control pills) containing estrogen or
Quinidine--The effects of these medicines may be decreased; use of a nonhormonal method of birth control or an oral contraceptive containing only a progestin may be necessary
Fluvoxamine (e.g., Luvox)--Blood levels of carbamazepine may be increased, increasing the risk of unwanted effects
Isoniazid (e.g., INH)--The risk of serious side effects may be increased
Itraconazole (e.g., Sporanox) or
Ketoconazole (e.g., Nizoral)--The effects of these medicines may be decreased
Monoamine oxidase (MAO) inhibitors (furazolidone [e.g., Furoxone], isocarboxazid [e.g., Marplan], phenelzine [e.g., Nardil], procarbazine [e.g., Matulane], selegiline [e.g., Eldepryl], tranylcypromine [e.g., Parnate])--Taking carbamazepine while you are taking or within 2 weeks of taking monoamine oxidase (MAO) inhibitors may cause sudden high body temperature, extremely high blood pressure, and severe convulsions; at least 14 days should be allowed between stopping treatment with one medicine and starting treatment with the other
Other anticonvulsants (seizure medicine)--The effects of these medicines may be decreased; in addition, if these medicines and carbamazepine are used together during pregnancy, the risk of birth defects may be increased
Risperidone [e.g., Risperdal]--The effects of risperidone may be decreased
Tricyclic antidepressants (amitriptyline [e.g., Elavil], amoxapine [e.g., Asendin], clomipramine [e.g., Anafranil], desipramine [e.g., Pertofrane], doxepin [e.g., Sinequan], imipramine [e.g., Tofranil], nortriptyline [e.g., Aventyl], protriptyline [e.g., Vivactil], trimipramine [e.g., Surmontil])--Central nervous system depressant effects of carbamazepine may be increased while the anticonvulsant effects of carbamazepine may be decreased; seizures may occur more frequently
Other medical problems--The presence of other medical problems may affect the use of carbamazepine. Make sure you tell your doctor if you have any other medical problems, especially:

Alcohol abuse (or history of)--Drinking alcohol may decrease the effectiveness of carbamazepine
Anemia or other blood problems or
Behavioral problems or
Glaucoma or
Heart or blood vessel disease or
Problems with urination--Carbamazepine may make the condition worse
Diabetes mellitus (sugar diabetes)--Carbamazepine may cause increased urine glucose levels
Kidney disease or
Liver disease--Higher blood levels of carbamazepine may result, increasing the chance of side effects
 

Proper Use of This Medicine
Carbamazepine suspension and tablets should be taken with meals to lessen the chance of stomach upset (nausea and vomiting). Carbamazepine extended-release capsules do not need to be taken with meals unless they upset your stomach. The contents of these extended-release capsules may be sprinkled over a teaspoonful of applesauce or other similar food; the capsule or its contents should not be crushed or chewed.

It is very important that you take this medicine exactly as directed by your doctor to obtain the best results and lessen the chance of serious side effects. Do not take more of it, do not take it more often, and do not take it for a longer time than your doctor ordered.

If you are taking this medicine for pain relief:

Carbamazepine is not an ordinary pain reliever. It should be used only when a doctor prescribes it for certain kinds of pain. Do not take carbamazepine for any other aches or pains .

If you are taking this medicine for epilepsy:

Do not suddenly stop taking this medicine without first checking with your doctor . To keep your seizures under control, it is usually best to gradually reduce the amount of carbamazepine you are taking before stopping completely.

Dosing--The dose of carbamazepine will be different for different patients. Follow your doctor's orders or the directions on the label . The following information includes only the average doses of carbamazepine. If your dose is different, do not change it unless your doctor tells you to do so.

The number of tablets or teaspoonfuls of suspension that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are taking carbamazepine .

For oral dosage form (suspension):
For epilepsy:
Adults and teenagers--At first, 100 milligrams (mg) taken up to four times a day. Your doctor may increase your dose if needed. However, the dose is usually not more than 1200 mg a day.
Children 6 to 12 years of age--At first, 50 mg taken four times a day. Your doctor may increase your dose if needed. However, the dose is usually not more than 1000 mg a day.
Children up to 6 years of age--Dose is based on body weight and will be determined by your doctor.
For trigeminal neuralgia:
Adults and teenagers--At first, 50 mg four times a day. Your doctor may increase your dose if needed. However, the dose is usually not more than 1200 mg a day.
Children--Use and dose must be determined by your doctor.
For oral dosage form (tablets and chewable tablets):
For epilepsy:
Adults and teenagers--At first, 200 mg taken two times a day. Your doctor may increase your dose if needed. However, the dose is usually not more than 1200 mg a day.
Children 6 to 12 years of age--At first, 100 mg taken two times a day. Your doctor may increase your dose if needed. However, the dose is usually not more than 1000 mg a day.
Children up to 6 years of age--Dose is based on body weight and will be determined by your doctor.
For trigeminal neuralgia:
Adults and teenagers--At first, 100 mg taken two times a day. Your doctor may increase your dose if needed. However, the dose is usually not more than 1200 mg a day.
Children--Use and dose must be determined by your doctor.
For oral extended-release capsule dosage form:
For epilepsy:
Adults and teenagers--At first, 200 mg taken one or two times a day. Your doctor may increase your dose if needed. However, the dose is usually not more than 1200 mg a day.
Children up to 12 years of age--Dose is based on body weight and will be determined by your doctor. However, the dose is usually not more than 1000 mg a day.
For trigeminal neuralgia:
Adults and teenagers--At first, 200 mg a day. Your doctor may increase your dose if needed. However, the dose is usually not more than 1200 mg a day.
Children--Use and dose must be determined by your doctor.
For oral extended-release tablet dosage form:
For epilepsy:
Adults and teenagers--At first, 100 to 200 mg taken one or two times a day with meals. Your doctor may increase your dose if needed. However, the dose is usually not more than 1200 mg a day.
Children 6 to 12 years of age--At first, 100 to 200 mg taken in smaller doses during the day. Your doctor may increase your dose if needed. However, the dose is usually not more than 1000 mg a day.
Children up to 6 years of age--Use and dose must be determined by your doctor.
For trigeminal neuralgia:
Adults and teenagers--At first, 100 mg taken two times a day. Your doctor may increase your dose if needed. However, the dose is usually not more than 1200 mg a day.
Children--Use and dose must be determined by your doctor.

Missed dose--If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses. However, if you miss more than one dose a day, check with your doctor.

Storage--To store this medicine:

Keep out of the reach of children.
Store away from heat and direct light.
Do not store the tablet forms of carbamazepine in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down and become less effective .
Keep the liquid form of this medicine from freezing.
Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of the reach of children.
 

Precautions While Using This Medicine
It is very important that your doctor check your progress at regular visits . Your doctor may want to have certain tests done to see if you are receiving the right amount of medicine or if certain side effects may be occurring without your knowing it. Also, the amount of medicine you are taking may have to be changed often.

This medicine will add to the effects of alcohol and other CNS depressants (medicines that cause drowsiness). Some examples of CNS depressants are antihistamines or medicine for hay fever, other allergies, or colds; sedatives, tranquilizers, or sleeping medicine; prescription pain medicine or narcotics; barbiturates; medicine for seizures; muscle relaxants; or anesthetics, including some dental anesthetics. Check with your doctor before taking any of the above while you are using this medicine .

This medicine may cause some people to become drowsy, dizzy, lightheaded, or less alert than they are normally, especially when they are starting treatment or increasing the dose. It may also cause blurred or double vision, weakness, or loss of muscle control in some people. Make sure you know how you react to this medicine before you drive, use machines, or do anything else that could be dangerous if you are not alert and well-coordinated or able to see well .

Some people who take carbamazepine may become more sensitive to sunlight than they are normally. Exposure to sunlight, even for brief periods of time, may cause a skin rash, itching, redness or other discoloration of the skin, or a severe sunburn. When you begin taking this medicine:

Stay out of direct sunlight, especially between the hours of 10:00 a.m. and 3:00 p.m., if possible.
Wear protective clothing, including a hat. Also, wear sunglasses.
Apply a sun block product that has a skin protection factor (SPF) of at least 15. Some patients may require a product with a higher SPF number, especially if they have a fair complexion. If you have any questions about this, check with your health care professional.
Apply a sun block lipstick that has an SPF of at least 15 to protect your lips.
Do not use a sunlamp or tanning bed or booth.

If you have a severe reaction from the sun, check with your doctor .

Oral contraceptives (birth control pills) containing estrogen may not work properly if you take them while you are taking carbamazepine. Unplanned pregnancies may occur. You should use a different or additional means of birth control while you are taking carbamazepine . If you have any questions about this, check with your health care professional.

For diabetic patients:

Carbamazepine may affect urine sugar levels. While you are using this medicine, be especially careful when testing for sugar in your urine. If you notice a change in the results of your urine sugar tests or have any questions about this, check with your doctor.

For patients taking the oral suspension form of Tegretol : Do not take any other liquid medicines at the same time that you take your dose of Tegretol without first checking with your doctor.

Before having any medical tests, tell the medical doctor in charge that you are taking this medicine. The results of some pregnancy tests and the metyrapone test may be affected by this medicine.

Before having any kind of surgery, dental treatment, or emergency treatment, tell the medical doctor or dentist in charge that you are taking this medicine . Taking carbamazepine together with medicines that are used during surgery or dental or emergency treatments may increase the CNS depressant effects and cause other unwanted effects.

Your doctor may want you to carry a medical identification card or bracelet stating that you are taking this medicine.
 
 

Side Effects of This Medicine
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

Rare

Black, tarry stools; blood in urine or stools; bone or joint pain; cough or hoarseness; darkening of urine; lower back or side pain; nosebleeds or other unusual bleeding or bruising; painful or difficult urination; pain, tenderness, swelling, or bluish color in leg or foot; pale stools; pinpoint red spots on skin; shortness of breath or cough; sores, ulcers, or white spots on lips or in the mouth; sore throat, chills, and fever; swollen or painful glands; unusual tiredness or weakness; wheezing, tightness in chest, or troubled breathing; yellow eyes or skin

Symptoms of overdose

Body spasm in which head and heels are bent backward and body is bowed forward; clumsiness or unsteadiness; convulsions (seizures)--especially in small children; dizziness (severe) or fainting; drowsiness (severe); fast or irregular heartbeat; high or low blood pressure (hypertension or hypotension); irregular, slow, or shallow breathing; large pupils; nausea or vomiting (severe); overactive reflexes followed by underactive reflexes; poor control in body movements (for example, when reaching or stepping); sudden decrease in amount of urine; trembling, twitching, or abnormal body movements

In addition, check with your doctor as soon as possible if any of the following side effects occur:

More common

Blurred vision or double vision; continuous back-and-forth eye movements

Less common

Behavioral changes (especially in children); confusion, agitation, or hostility (especially in the elderly); diarrhea (severe); headache (continuing); increase in seizures; nausea and vomiting (severe); skin rash, hives, or itching; unusual drowsiness

Rare

Chest pain; difficulty in speaking or slurred speech; fainting; frequent urination; irregular, pounding, or unusually slow heartbeat; mental depression with restlessness and nervousness or other mood or mental changes; muscle or stomach cramps; numbness, tingling, pain, or weakness in hands and feet; rapid weight gain; rigidity; ringing, buzzing, or other unexplained sounds in the ears; sudden decrease in amount of urine; swelling of face, hands, feet, or lower legs; trembling; uncontrolled body movements; visual hallucinations (seeing things that are not there)

Other side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. However, check with your doctor if any of the following side effects continue or are bothersome:

More common

Clumsiness or unsteadiness; dizziness (mild); drowsiness (mild); lightheadedness; nausea or vomiting (mild)

Less common or rare

Aching joints or muscles; constipation; diarrhea; dryness of mouth; headache; increased sensitivity of skin to sunlight (skin rash, itching, redness or other discoloration of skin, or severe sunburn); increased sweating; irritation or soreness of tongue or mouth; loss of appetite; loss of hair; sexual problems in males; stomach pain or discomfort

Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.
 
 

Additional Information
Once a medicine has been approved for marketing for a certain use, experience may show that it is also useful for other medical problems. Although these uses are not included in product labeling, carbamazepine is used in certain patients with the following medical conditions:

Neurogenic pain (a type of continuing pain)
Bipolar disorder (manic-depressive illness)
Central partial diabetes insipidus (water diabetes)
Alcohol withdrawal
Psychotic disorders (severe mental illness)

Other than the above information, there is no additional information relating to proper use, precautions, or side effects for these uses.
 
 

Carbamazepine links:
Carbamazepine (Oral) - Yahoo! Health
Carbamazepine - RxList Monographs
MEDLINEplus Drug Information: Carbamazepine (Systemic)
Understanding Pain Mechanisms in Multiple Sclerosis
Multiple sclerosis: the disease and its treatment
Carbamazepine Intoxication Is Common
FDA Finds Moisture Causes Epilepsy Pill to Weaken
Treatment of cerebellar tremors with carbamazepine
Treatment of paroxysmal disorders in multiple sclerosis with carbamazepine (Tegretol)

MS Glossary
All About Multiple Sclerosis