Carbamazepine CR: Uses, Side Effects and Dosage

ABOUT THIS MEDICATION

What the medication is used for:

Carbamazepine CR has been prescribed for you by your doctor:

• to reduce your number of seizures;
• to relieve the pain of trigeminal neuralgia;
• to treat your acute mania or bipolar disorder.

What it does:

Carbamazepine CR belongs to the family of medicines called anticonvulsants for treating epilepsy. Carbamazepine CR is also used for treating the pain of trigeminal neuralgia and for treating mania.

If you have any questions about how Carbamazepine CR works or why this medicine has been prescribed to you, ask your doctor.

When it should not be used:

You should not use Carbamazepine CR if:

• You are allergic (hypersensitive) to carbamazepine or to any

  of the other ingredients of Carbamazepine CR (See What the non-medicinal ingredients are) If you think you may be allergic, ask your doctor for advice. Do not take Carbamazepine CR if you are allergic to other tricyclic drugs such as amitriptyline, trimipramine, imipramine.

• You have severe heart disease (heart block).
• You have liver disease.
• You have a history of bone marrow depression.
• You have had serious blood illnesses in the past.

• You have a disturbance in the production of porphyrin, a

  pigment important for liver function and blood formation (also called hepatic porphyria).

• You are also taking medicines belonging to a special group of

  antidepressants called monoamine-oxidase inhibitors (MAOIs).

• You are also taking the drugs itraconazole or voriconazole

  (Vfend) for treatment of an infection.

• Carbamazepine CR should not be used to relieve trivial pain in

  the face or headaches.

If any of the above applies to you, tell your doctor before taking Carbamazepine CR.

What the medicinal ingredient is:

Carbamazepine.

What the important nonmedicinal ingredients are:

Carbamazepine CR 200 mg and 400 mg: acrylic esters, cellulose compounds, iron oxides, magnesium stearate, silicon dioxide, talc, titanium dioxide, castor oil derivative.

What dosage forms it comes in:

Carbamazepine CR is available in the following forms:

• CR tablets (controlled-release tablets, which can be divided)

  containing 200 mg or 400 mg carbamazepine.

WARNINGS AND PRECAUTIONS

Serious Warnings and Precautions

• Blood: Although infrequently reported and very rarely fatal, serious adverse effects affecting blood cell counts have been observed during the use of Carbamazepine CR. Other side effects include: low white blood cell count, bone marrow depression, hepatitis and signs of liver failure such as jaundice (yellowing of the skin or eyes). Contact your doctor immediately if you are experiencing any of these symptoms. Close clinical and frequent laboratory supervision with your doctor should be maintained throughout treatment with Carbamazepine CR in order to detect as early as possible any possible signs of a blood disorder. Your doctor should discontinue Carbamazepine CR, if there is significant evidence of a bone marrow depression.
• Skin: Serious and sometimes fatal skin reactions known as Toxic Epidermal Necrolysis (TEN) and Stevens-Johnson Syndrome (SJS), have been reported with carbamazepine. Other serious skin reactions such as Drug Rash with Eosinophilia and Systemic Symptoms (DRESS), Acute Generalized Exanthematous Pustulosis (AGEP) and Maculopapular Rash have also been reported. Although very rare, serious forms of DRESS and AGEP may also lead to death. Some cases of these skin reactions have been genetically linked. Your doctor may recommend a blood test to determine if you belong to an at-risk population.

• Contact your doctor immediately if you are developing any combination of:

  • a rash or any serious skin reactions such as red skin, blistering of the lips, eyes or mouth, and skin peeling accompanied by fever
  • swollen lymph nodes
  • joint pain
  • enlargement of the liver and/or the spleen
  • problems related to the lungs, kidneys, pancreas, heart, bone marrow, thymus, and colon

Your doctor will determine if it is indeed drug-related and discontinue Carbamazepine CR in this case.

• Cancer: Long-term toxicity studies in rats have

  indicated a possible cancer risk associated with carbamazepine. Before taking Carbamazepine CR, discuss with your doctor the potential benefits and possible risks of this treatment for you.

BEFORE you use Carbamazepine CR talk to your doctor or pharmacist:

• About your medical conditions, especially if you have or have

  had any liver, kidney, heart or thyroid disease or blood disorders (including those caused by other drugs).

• If you have a history, or family history, of bone disease or

  have taken antiepileptics (such as phenobarbital, phenytoin, primidone, oxcarbazepine, lamotrignine, sodium valproate and/or carbamezepine) for a prolonged period of time.

• If you are taking delavirdine, a medicine used to treat HIV-1

  infection.

• About any allergies you may have, especially if you have ever

  shown any unusual sensitivity (rash or other signs of allergy) to oxcarbazepine or other drugs used to treat your condition. It is important to note that if you are allergic to carbamazepine, there is an approximately 1 in 4 (25%) chance that you could also have an allergic reaction to oxcarbazepine.

• If you are pregnant. Your doctor may recommend that you

  take folic acid before and during your pregnancy and vitamin K during the last weeks of pregnancy. Your doctor may also recommend that the newborn receive vitamin K and be observed for liver and gall bladder problems.

• If you are pregnant or planning on becoming pregnant to

  discuss the potential risk of taking Carbamazepine CR during pregnancy since it may cause harm or abnormalities in the unborn child.

• If you are a female of childbearing age you should use an

  effective method of contraception throughout your treatment and for 2 weeks after your last dose. If you are taking hormonal contraceptive (birth control medicine). Carbamazepine CR may render this contraceptive ineffective. Therefore, you should use a different or additional non-hormonal method of contraception while you are taking Carbamazepine CR. This should help to prevent an unwanted pregnancy.

• If you get irregular vaginal bleeding or spotting.

• If you are breast-feeding. Carbamazepine CR is known to pass

  into breast milk. You must discuss with your doctor the benefits of breastfeeding against any possible risks to the infant. If you decide to breastfeed, the baby must be observed for liver and gall bladder problems, drowsiness, and allergic skin reactions.

• About any other medicines (prescription and non-prescription)

  you are taking.

• About your usual alcohol consumption.

• If you have increased pressure in the eye (glaucoma).

  • If you have difficulty passing urine (urinary retention).
  • If you were told by your physician that you suffer from mental problems, a mental disorder called psychosis that may be accompanied by confusion or agitation, or have thoughts about suicide.

If any of the following apply to you, tell your doctor.

• If an allergic reaction happens such as fever with lymph nodes swelling, rash or skin blistering, tell your doctor immediately or go to the emergency department at your nearest hospital. (See Side effects and what to do about them).
• If you experience an increase in the number of seizures, tell your doctor immediately.
• If you experience any side effects such as drowsiness, headache, unsteadiness on the feet, double vision, dizziness, nausea or vomiting, consult your doctor.
• If, at any time, you have thoughts of harming or killing yourself. A small number of people being treated with antiepileptic drugs have reported having such thoughts or behavior. Should this happen to you, or to those in your care if you are a caregiver or guardian, talk to your doctor immediately. Close observation by a doctor is necessary in this situation. Do not discontinue your medication on your own.
• If you have kidney problems associated with low sodium blood level or if you have kidney problems and you are also taking certain medicines that lower sodium blood level (diuretics such as hydrochlorothiazide, furosemide).
• If you experience dizziness, drowsiness, decrease in blood pressure, confusion, due to Carbamazepine CR treatment, which may lead to falls.

Carbamazepine CR may affect male fertility or cause abnormal sperm.

Periodic eye examinations are recommended while taking Carbamazepine CR.

Do not drive a car or operate dangerous machinery until you are sure that Carbamazepine CR does not cause dizziness, drowsiness, sleepiness, blurred or double vision, affect your muscular coordination or affect your alertness.

INTERACTIONS WITH THIS MEDICATION

Tell your doctor or pharmacist if you are taking or have recently taken any prescription, non-prescription medicines or natural health products. It is particularly important for Carbamazepine CR, since many other medicines interact with it.

You may need a change in your dose or, sometimes, to stop one of these other medicines.

Irregularity of the menstrual period may occur in women taking hormonal contraceptives (birth control medicines) and Carbamazepine CR. The hormonal contraceptive may become less effective and you should use another different or additional non-hormonal contraceptive method.

• Avoid alcohol consumption when taking Carbamazepine CR.

• Do not drink grapefruit juice or eat grapefruit since this can

  increase the effect of Carbamazepine CR. Other juices, like orange juice or apple juice, do not have this effect.

PROPER USE OF THIS MEDICATION

Usual dose:

Dosage should be individualised. It is very important that you take Carbamazepine CR exactly as your doctor instructed.

• Never increase or decrease the recommended dose of

  Carbamazepine CR you are taking unless your doctor tells you to.

• If you are taking Carbamazepine CR, do not suddenly stop

  taking it without first checking with your doctor. Your doctor will tell you if and when you can stop taking this medicine

• Carbamazepine CR tablets should be swallowed unchewed

  with a little liquid during or after a meal.

Adults and Children Over 12 Years of Age

Initial dose 100 to 200 mg once or twice a day. Your doctor will decide the best dosage for you. Always follow your doctor’s instructions.

For the treatment of trigeminal neuralgia, the maximum dose is 1200 mg a day.

Children 6-12 Years of Age

Initial dose 100 mg in divided doses on the first day. Your doctor will decide the best dosage for you. Always follow your doctor’s instructions.

Overdose:

If you think you have taken too much Carbamazepine CR, contact a healthcare professional, hospital emergency department or regional Poison Control Centre immediately, even if there are no symptoms.

Missed Dose:

If you miss a dose, take your Carbamazepine CR as soon as possible. However, if the time is close to the next dose, do not take the missed dose and return to your regular dosing schedule. Do not double the dose to make up for the forgotten dose.

SIDE EFFECTS AND WHAT TO DO ABOUT THEM

Side effects may include:

• purple or reddish-purple bumps that may be itchy

  • trembling, uncontrolled body movements, muscle spasm, loss of muscle coordination, weakness
  • agitation or hostility (especially in the elderly), depression with restlessness, nervousness or other mood or mental changes, changes in behaviour, confusion, headache, memory loss
  • blurred vision, double vision, itching with redness and swelling of the eye (conjunctivitis), uncontrolled eye movements
  • difficulty speaking or slurred speech, taste disturbances, dry mouth, red and sore tongue, mouth sores
  • ringing or other unexplained sounds in the ears, decreased hearing
  • numbness, tingling in hands and feet
  • unusual secretion of breast milk, breast enlargement in men, sexual disturbances (erectile dysfunction), male infertility
  • increased sensitivity of the skin to sun, alterations in skin pigmentation, acne, increased sweating
  • reactivation of herpes virus infection (can be serious when the immune system is depressed)
  • complete loss of the nails, loss of hair, excessive body and facial hair
  • vomiting, nausea, loss of appetite, constipation, diarrhea, abdominal pain
  • dizziness, sleepiness, unsteadiness, drowsiness, fatigue
  • weight gain
  • aching joints or muscles
  • experience a fall due to dizziness, drowsiness, decrease in blood pressure, confusion

Long-term use of antiepileptics such as carbamazepine, phenobarbital, phenytoin, primidone, oxcarbazepine, lamotrigine and sodium valproate is associated with a risk of decreased bone mineral density that may lead to weakened or brittle bones, or fracture.

If any of these affects you severely, contact your doctor

Carbamazepine CR can cause abnormal blood test results. Your doctor will decide when to perform blood tests and will interpret the results.

This is not a complete list of side effects. For any unexpected effects while taking Carbamazepine CR, contact your doctor or pharmacist.

HOW TO STORE IT

Store at room temperature (Carbamazepine CR store below 25°C).

• Protect from humidity, such as in bathrooms where you shower often.
• Keep out of reach and sight of children.

REPORTING SIDE EFFECTS

You can report any suspected side effects associated with the use of health products to Health Canada by:

• Visiting the Web page on Adverse Reaction Reporting

  (https://www.canada.ca/en/health-canada/services/drugs-health-products/medeffect-canada/adverse-reaction-reporting.html) for information on how to report online, by mail or by fax; or

• Calling toll-free at 1-866-234-2345.

NOTE: Contact your health professional if you need information about how to manage your side effects. The Canada Vigilance Program does not provide medical advice.

MORE INFORMATION

If you want more information about Carbamazepine CR:

• Talk to your healthcare professional

• Find the full product monograph that is prepared for healthcare professionals and includes this Consumer Information by visiting the Health Canada website (https://www.canada.ca/en/health-canada.html); or by contacting Pro Doc Ltée at 1-800-361-8559, www.prodoc.qc.ca or info@prodoc.qc.ca.

  Pro Doc Ltée, Laval, Québec, H7L 3W9

Last revised: August 14, 2019