Gen-Carbamazepine CR

Brand Name:Apo-Carbamazepine, Novo-Carbamaz, Nu-Carbamazepine, PMS-Carbamazepine, Taro-Carbamazepine, Tegretol Chewtabs, Tegretol Suspension, Tegretol Tablets, Tegretol CR

Prescription needed: Yes

What is this drug used for?

Carbamazepine belongs to a class of medications called anticonvulsants, which are primarily used to treat seizures in certain types of epilepsy. Carbamazepine is also commonly used to treat severe nerve pain that is seen with conditions like trigeminal neuralgia and diabetic neuropathy. In addition, it can be used for some mental conditions such as acute mania or bipolar disorder.

Is there any reason not to take this drug?

You should not take this drug if you are allergic to carbamazepine or to amitriptyline, imipramine, desipramine and/or nortriptyline. It should be used with extreme caution in people with a condition called AV heart block. Before taking this medication, tell your doctor specifically if you have or have ever had:
  • an allergic reaction to other seizure medications like phenytoin or phenobarbital
  • any blood problems (bruising, bleeding, anemia, low white blood cells)
  • feelings of being depressed, agitated or confused
  • problems with the kidney or liver
  • glaucoma
  • heart disease or other heart problems
  • a certain type of seizure called, absence seizures
  • difficulty going to the bathroom (e.g. urinary incontinence or urinary retention)
  • a problem with alcohol or drug abuse

What about possible side effects?

The most common side effects to this medication include:
  • clumsiness and feeling unsteady on your feet
  • dizziness, lightheadedness
  • drowsiness and feeling tired
  • headache
  • loss of appetite
  • nausea
  • vomiting
  • seeing double (double vision) or blurry vision
  • rash, itching and increase sensitivity to the sun

These side effects usually occur at the start of therapy and with higher doses. They may go away with time but may also be less severe by lowering the dose and increasing the medication more slowly. Talk to your doctor or pharmacist regarding the best way to take the medication.

Other less common and possibly severe side effects include:

Call your doctor immediately if you experience any of the following side effects:

  • swelling of the feet and ankles
  • weight gain
  • low sodium levels in the blood
  • feeling agitated or confused - rare
  • a condition called thrombocytopenia or leukopenia - call your doctor immediately if you experience unusual bleeding, bruising, unexplained sore throat, fever, chills, or other signs of infection
  • liver problems - rare; call your doctor if you experience unexplained nausea, vomiting, stomach pain, fatigue, loss of appetite, dark urine, yellowing of the skin and/or eyes
  • problems with heart rhythm - rare; call your doctor if you notice a fast or irregular heart beat
  • severe rashes and hives - rare; call your doctor immediately if you experience painful red spots, blistering or peeling of skin
  • problems with the kidney - rare
  • A condition called agranulocytosis or aplastic anemia - these are very rare side effects (occurring in < 0.01% of the population)

This is not a complete list of side effects. If you are concerned about these or other unusual symptoms while taking this medication, ask your doctor and/or pharmacist for more information and advice.

What if I am taking other drugs?

Carbamazepine can affect or be affected by other medications in many different ways. Many of these medications need special monitoring and/or have significant side effects. Therefore, it is extremely important that you let all healthcare providers know that you are taking this medication.

Always provide your doctor with a list of all other drugs you are taking (including over-the-counter medications and herbal/natural products) as they may interact with and/or may change the safety or effectiveness of either drug. Tell your doctor specifically if you are taking any of these drugs as he/she may need to make changes or monitor you more closely:

  • Warfarin - may decrease how well warfarin can work
  • phenelzine, tranylcypromine, moclobemide, and other MAO inhibitors - avoid the use of these drugs together; must wait at least 2 weeks after stopping one before you can start the other
  • Itraconazole, ketoconazole, fluconazole, cimetidine, HIV protease inhibitors (e.g. ritonavir), amiodarone, clarithromycin, erythromycin, diltiazem, verapamil, fluoxetine - may increase the amount of carbamazepine in your blood and increase your chances for side effects
  • drugs that can cause tiredness, sedation, dizziness:
  • antihistamines (e.g. diphenhydramine, hydroxyzine)
  • opioid pain medications (e.g. codeine, oxycodone, morphine, hydromorphone)
  • antidepressants (e.g. amitriptyline, trazodone) and antipsychotics (e.g. risperidone, haloperidol)
  • muscle relaxants (e.g. cyclobenzaprine)
  • other drugs for epilepsy (gabapentin, phenytoin, phenobarbital, valproic acid)
  • medicine for insomnia or anxiety (e.g. alprazolam, diazepam, lorazepam, temazepam)
  • phenytoin, phenobarbital, St. John’s Wort, rifampin, theophylline - may see a decrease in the amount of carbamazepine in the blood
  • lithium, metoclopramide, haloperidol - increases chance for similar side effects
  • isoniazid
  • birth control pills - may see a decrease in the amount of this drug in your blood, thus decreasing how well it can work to prevent pregnancy and increasing chance for breakthrough bleeding
  • carbamazepine can decrease the blood levels of many other drugs - talk to your doctor or pharmacist

This is not a complete list of drug interactions. Ask your doctor or pharmacist to review your list of medications.

Other information:

Lab Tests: It is extremely important that you have your blood tested as recommended by your doctor. These blood tests are necessary to make sure you have the right amount of drug in your body. This ensures that the drug works properly and decreases your chances of experiencing side effects. Your doctor will also order regular blood tests to check your kidney and liver function.

Sun-Protection: Your skin may burn more easily while taking this medication – it is therefore advised that you use sunblock and wear protective clothing to decrease the chance of this happening.

Onset of pain relief: It may take some time (1-2 weeks) to see an improvement in pain. If you don’t have any relief after two weeks, call your doctor as your dose may need to be increased. If you notice any changes in how much relief you are getting, be sure to let your doctor know.

Children: Lower doses are necessary.

Seniors: Lower doses are necessary. Will be more sensitive to the side effects caused by this medication, especially at the start of therapy.

Pregnancy: May cause harm to unborn fetus. Talk to your doctor.

Women who are nursing: Drug passes to breast milk, but at normal doses adverse effects on baby are unlikely. Talk to your doctor.

People who drive or operate machinery: Do not do so until you know how this drug affects you personally.

Overdose: If you experience any unusual reactions or if you seriously exceed the recommended dosage, call your doctor or 911.

Stopping the drug: Do not stop taking this drug without first talking to your doctor. Stopping this drug quickly may cause seizures to occur. If the drug needs to be stopped, your doctor will likely want to reduce your dose gradually.

If you miss a dose: Take as soon as you remember. However if it is almost time for your next scheduled dose, skip the missed dose and go back to your regular dosing schedule. Do not take a double dose. If you miss more than one dose in a day, talk to your doctor. If you are unsure of what to do, talk to your doctor or pharmacist.

Storage conditions: Closed container; cool, dry location away from excess moisture (not in the bathroom); direct light, always out of reach of children.

Alcohol: Should be avoided if possible as it can increase the chance of side effects.

Dietary Precautions: Avoid eating grapefruit or drinking grapefruit juice as it may increase the amount of carbamazepine in the blood.