What is/are Carbamazepine?
Carbamazepine (CBZ) (Tegretol, Equetro) is an anticonvulsant and mood-stabilizing drug used primarily in the treatment of epilepsy and bipolar disorder, as well as trigeminal neuralgia. It is also used off-label for a variety of indications, including attention-deficit hyperactivity disorder (ADHD), schizophrenia, phantom limb syndrome, complex regional pain syndrome, paroxysmal extreme pain disorder, neuromyotonia, intermittent explosive disorder, borderline personality disorder, Myotonia congenita and post-traumatic stress disorder.
Like other anticonvulsants, intrauterine exposure is associated with spina bifida and neurodevelopmental problems.
Carbamazepine is typically used for the treatment of seizure disorders and neuropathic pain. It may be used as a second line treatment for bipolar disorder and along with antipsychotic agents in schizophrenia.
In the United States, the FDA-approved indications are epilepsy (including partial seizures and tonic-clonic seizures), trigeminal neuralgia, and manic and mixed episodes of bipolar I disorder. Although data are still lacking, carbamazepine appears to be as effective and safe as lithium for the treatment of bipolar disorder, both in the acute and maintenance phase.
Common adverse effects may include drowsiness, headaches and migraines, motor coordination impairment, and/or upset stomach. Carbamazepine preparations typically greatly decrease a person's alcohol tolerance.
Less common side-effects may include cardiac arrhythmias, blurry or double vision and/or the temporary loss of blood cells or platelets and in rare cases can cause aplastic anemia or agranulocytosis. With normal use, small reductions in white cell count and serum sodium are common; however, in rare cases, the loss of platelets may become life-threatening. In this case a doctor may recommend frequent blood tests during the first few months of use, followed by three to four tests per year for established patients. Additionally, carbamazepine may possibly exacerbate preexisting cases of hypothyroidism, so yearly thyroid function tests are advisable for persons taking the drug.
There are also rare reports of an auditory side-effect for carbamazepine use, whereby patients perceive sounds about a semitone lower than previously. Thus, middle C would be heard as the note B3 just below it, and so on. The inverse effect (that is, notes sounding higher) has also been recorded. This unusual side-effect is usually not noticed by most people, and quickly disappears after the person stops taking carbamazepine.
Carbamazepine increases the risk of developing lupus by 88% (odds ratio of 1.88), with the effect possibly restricted to women.
Oxcarbazepine, a derivative of carbamazepine, reportedly has fewer and less serious side-effects.
Carbamazepine may cause syndrome of inappropriate antidiuretic hormone (SIADH), since it both increases the release and potentiates the action of ADH (vasopressin).
Carbamazepine may aggravate juvenile myoclonic epilepsy, so it is important to uncover any history of jerking, especially in the morning, before starting the drug. It may also aggravate other types of generalized seizure disorder, particularly absence seizures.
In addition, carbamazepine has been linked to serious adverse cognitive anomalies, including EEG slowing and apoptosis of cultured cerebellar neurons.
The FDA informed health care professionals that dangerous or even fatal skin reactions (Stevens–Johnson syndrome and toxic epidermal necrolysis), that can be caused by carbamazepine therapy, are significantly more common in patients with a particular human leukocyte antigen (HLA) allele, HLA-B*1502. This allele occurs almost exclusively in patients with ancestry across broad areas of Asia, including South Asian Indians. In Europeans a large proportion of sensitivity is associated with HLA-B58. Researchers have also identified another genetic variant, HLA-A*3101 which has been shown to be a strong predictor of both mild and severe adverse reactions to carbamazepine among Japanese and Europeans.
Mechanism of action
The mechanism of action of carbamazepine and its derivatives is relatively well-understood. Carbamazepine stabilizes the inactivated state of Voltage-gated sodium channels, making fewer of these channels available to subsequently open. This leaves the affected cells less excitable until the drug dissociates. Carbamazepine has also been shown to potentiate GABA receptors made up of alpha1, beta2, gamma2 subunits.such as neuopathic pain and manic-depressive illness
Tegretol is used for:
Controlling certain types of epileptic seizures. It is also used to treat severe pain of the jaw or cheek caused by a facial nerve problem (trigeminal neuralgia). It may also be used for other conditions as determined by your doctor.
Tegretol is an anticonvulsant. It works to control seizures by blocking certain nerve impulses in the brain. It works to treat trigeminal neuralgia by altering nerve impulses in certain facial nerves, which relieves pain.
Do NOT use Tegretol if:
you are allergic to any ingredient in Tegretol you are allergic to tricyclic antidepressants (eg, amitriptyline), cyclobenzaprine, or similar medicines you have a history of bone marrow problems, the blood disorder porphyria, or other serious blood disorders you have a severe heart problem called heart block (atrioventricular block) you are taking nefazodone you are taking a monoamine oxidase inhibitor (MAOI) (eg, phenelzine) or have taken an MAOI within the last 14 days
Contact your doctor or health care provider right away if any of these apply to you.
Before using Tegretol :
Some medical conditions may interact with Tegretol . Tell your doctor or pharmacist if you have any medical conditions, especially if any of the following apply to you:
if you are pregnant, planning to become pregnant, or are breast-feeding if you are taking any prescription or nonprescription medicine, herbal preparation, or dietary supplement if you have allergies to medicines, foods, or other substances if you are allergic to other seizure medicines (eg, phenytoin, phenobarbital) if you have a history of other types of seizures (eg, absence, atonic), increased pressure in the eye (eg, glaucoma), liver or kidney problems, mood or mental problems, suicidal thoughts or actions, or multiple sclerosis if you have a history of heart problems (eg, heart failure, heart block, irregular heartbeat), abnormal electrocardiogram (ECG), high blood pressure, or high blood cholesterol if you have a history of blood problems, including blood problems caused by other medicine if you have previously taken Tegretol
Some MEDICINES MAY INTERACT with Tegretol . Tell your health care provider if you are taking any other medicines, especially any of the following:
MAOIs (eg, phenelzine) because a severe reaction, including severe high blood pressure and high fever, may occur Nefazodone because its effectiveness may be decreased by Tegretol Many prescriptions and nonprescription medicines (eg, used for infections, mental or mood problems, allergies, pain, high blood pressure, cancer, asthma, inflammation, aches and pains, headaches, HIV, blood thinning, thyroid problems, seizures, birth control), multivitamin products, and herbal or dietary supplements (eg, St. John's wort) may interact with Tegretol , increasing the risk of side effects
This may not be a complete list of all interactions that may occur. Ask your health care provider if Tegretol may interact with other medicines that you take. Check with your health care provider before you start, stop, or change the dose of any medicine.
How to use Tegretol :
Use Tegretol as directed by your doctor. Check the label on the medicine for exact dosing instructions.
Take Tegretol by mouth with or without food.
Eating grapefruit or drinking grapefruit juice may increase the risk of Tegretol 's side effects. Talk with your doctor before including grapefruit or grapefruit juice in your diet.
Do not suddenly stop taking Tegretol . You may have an increase risk of side effects (eg, seizures). If you need to stop Tegretol or add a new medicine, your doctor will gradually lower your dose.
Take Tegretol on a regular schedule to get the most benefit from it.
Taking Tegretol at the same time each day will help you remember to take it.
Continue to take Tegretol even if you feel well. Do not miss any doses.
If you miss a dose of Tegretol , take it as soon as possible. If it is almost time for your next dose, skip the missed dose. Go back to your regular dosing schedule. Do not take 2 doses at once.
Ask your health care provider any questions you may have about how to use Tegretol .
Important safety information:
Tegretol may cause drowsiness, dizziness, or blurred vision. These effects may be worse if you take it with alcohol or certain medicines. Use Tegretol with caution. Do not drive or perform other possibly unsafe tasks until you know how you react to it.
Check with your doctor before you drink alcohol while you are using Tegretol .
Do not take more than the recommended dose without checking with your doctor.
Tegretol may lower the ability of your body to fight infection. Avoid contact with people who have colds or infections. Tell your doctor if you notice signs of infection like fever, sore throat, rash, or chills.
Tegretol may reduce the number of clot-forming cells (platelets) in your blood. Avoid activities that may cause bruising or injury. Tell your doctor if you have unusual bruising or bleeding. Tell your doctor if you have dark, tarry, or bloody stools.
Tegretol may cause you to become sunburned more easily. Avoid the sun, sunlamps, or tanning booths until you know how you react to Tegretol . Use a sunscreen or wear protective clothing if you must be outside for more than a short time.
Tell your doctor or dentist that you take Tegretol before you receive any medical or dental care, emergency care, or surgery.
Do not switch from the tablets form of Tegretol to the suspension form without checking with your doctor. The same dose may not have the same effects.
Tegretol may interfere with certain lab tests, including thyroid function tests. Be sure your doctor and lab personnel know you are using Tegretol .
Hormonal birth control (eg, birth control pills) may not work as well while you are using Tegretol . To prevent pregnancy, use an extra form of birth control (eg, condoms).
Tegretol may cause the results of some pregnancy tests to be wrong. Check with your doctor if you have questions or concerns about your pregnancy test results.
Lab tests, including complete blood cell counts, liver and kidney function, eye exams, and carbamazepine blood levels, may be performed while you use Tegretol . These tests may be used to monitor your condition or check for side effects. Be sure to keep all doctor and lab appointments.
Use Tegretol with caution in the ELDERLY; they may be more sensitive to its effects, especially agitation or confusion.
PREGNANCY and BREAST-FEEDING: Tegretol has been shown to cause harm to the fetus. If you think you may be pregnant, contact your doctor. You will need to discuss the benefits and risks of using Tegretol while you are pregnant. Tegretol is found in breast milk. Do not breast-feed while taking Tegretol .
Possible side effects of Tegretol :
All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome:
Dizziness; drowsiness; dry mouth; nausea; unsteadiness; vomiting.
Seek medical attention right away if any of these SEVERE side effects occur:
Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); black, tarry, or bloody stools; calf pain, swelling, or tenderness; change in the amount of urine produced; chest pain; confusion; dark urine; decreased coordination; fainting; fast or irregular heartbeat; fever, chills, or sore throat; hallucinations; joint pain; loss of appetite; mental or mood changes; pain, tenderness, or unusual swelling in the neck, groin, or under the arms; red, swollen, blistered, or peeling skin; severe or persistent dizziness or headache; severe or persistent nausea or vomiting; shortness of breath; speech problems; stomach pain; sudden unusual weight gain; suicidal thoughts or actions; swelling of the hands, ankles, or feet; swollen lymph nodes; ulcers or sores in the mouth; uncontrolled muscle movements; unusual bruising or bleeding; unusual tiredness; vision or eye problems; yellowing of the skin or eyes.
This article uses material from the Wikipedia article Carbamazepine, which is released under the Creative Commons Attribution-Share-Alike License 3.0.