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Home > Drug Category > Antiepileptic Medication > Tegretol CR and Equivalent

Tegretol CR (Carbamazepine Controlled Release) Information

Tegretol CR (carbamazepine controlled release) is a prescription medication formulated to provide a sustained release of the active ingredient, carbamazepine, over an extended period. It belongs to the phenyltriazine class and is approved as an anticonvulsant (antiepileptic drug or AED) and a mood stabilizer. The controlled-release mechanism is designed to minimize fluctuations between peak and trough plasma levels, potentially reducing dose-related side effects often seen with immediate-release (IR) formulations. It is indicated for the treatment of Partial Seizures (simple and complex), Generalized Tonic-Clonic Seizures, and mixed seizure patterns. In adults, it is also used for Trigeminal Neuralgia and the treatment of manic and mixed episodes of Bipolar I Disorder. Tegretol CR tablets are typically administered twice daily (BID). The CR formulation slows the rate of absorption compared to the IR tablet, leading to a later, lower peak concentration and a higher trough concentration, which helps maintain steady therapeutic levels. Like the IR form, it undergoes autoinduction of its hepatic metabolism via the CYP3A4 enzyme, resulting in a reduced steady-state half-life (12-17 hours). The primary therapeutic mechanism remains the same: stabilizing neuronal membranes by binding to and inhibiting voltage-sensitive sodium channels, thereby controlling excessive neuronal firing.

Tegretol CR Side Effects

The overall profile of side effects for Tegretol CR is similar to that of the immediate-release tablet. However, the controlled-release mechanism is designed to reduce the severity and incidence of concentration-dependent neurological effects. The most common side effects reported, particularly during the dose titration phase, include dizziness, drowsiness (somnolence), unsteadiness or ataxia (trouble with coordination), nausea, vomiting, and diplopia (double vision) or blurred vision. Due to its effect on the central nervous system, patients may also experience fatigue, dry mouth, or headache. A mild skin rash is a common occurrence which must always be reported to a physician.

However, more serious side effects can occur. If any of the following symptoms are experienced, a patient should seek immediate medical attention:

• Cardiac Conduction Abnormalities: Can affect heart rhythm, especially in individuals with pre-existing heart disease, potentially causing AV block.

• Hematologic Abnormalities (Boxed Warning): A Black Box Warning is also present for the potential development of severe blood disorders, including Aplastic Anemia and Agranulocytosis (severe decrease in white blood cells). Unexplained fever, easy bruising, or persistent sore throat may be signs.

• Hyponatremia (Low Sodium): A risk across all carbamazepine formulations, potentially causing confusion, fatigue, and seizure worsening.

• Liver Dysfunction: Indicated by symptoms like jaundice, persistent nausea, or loss of appetite, which can signal severe hepatic injury.

• Severe Dermatologic Reactions (Boxed Warning): Tegretol CR carries a Black Box Warning for a rare but potentially fatal risk of severe rashes, including Stevens-Johnson Syndrome (SJS), Toxic Epidermal Necrolysis (TEN), and Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS). Genetic testing for the HLA-B*1502 allele is critical for patients of Asian descent.

• Suicidal Thoughts and Behaviour (Boxed Warning for AEDs): Like all antiepileptic drugs, it can increase the risk of suicidal thoughts or behaviour; monitoring for changes in mood or behaviour is essential.

Tegretol CR Precautions

Tegretol CR shares all the critical precautions of the immediate-release formulation. It is contraindicated in patients with a known hypersensitivity to the drug, a history of bone marrow depression, AV block, or concurrent use of MAOIs. Due to the risk of severe hematologic and hepatic reactions, routine laboratory monitoring (CBC and LFTs) is necessary before and throughout treatment. Dosage should never be stopped abruptly to avoid the risk of withdrawal seizures. Patients of Asian descent should be screened for the HLA-B*1502 allele before beginning therapy. Tegretol CR is a potent enzyme inducer and can significantly decrease the effectiveness of co-administered medications, most notably hormonal contraceptives, requiring women of childbearing potential to use alternative or barrier methods. Concurrent use with lithium or nefopam may increase the risk of neurotoxicity/nephrotoxicity. Dosage adjustments may be necessary for patients with renal or hepatic impairment. Finally, patients must be warned to avoid grapefruit juice as it inhibits CYP3A4, thereby increasing carbamazepine blood levels and risk of toxicity.

Do I need a prescription to order Tegretol CR?

Yes, a prescription is required from your physician to order Tegretol CR.