What is the use of Carbamazepine (anticonvulsant medication)?

From the Guidelines

Carbamazepine should be used as a first-line agent for pain control in trigeminal neuralgia, with a starting dose of 200 mg at night and gradually increased by 200 mg every 7 days to a final dose of 400–1200 mg, divided in 2–3 doses per day, as it has been shown to provide partial or complete pain relief in 70% of patients 1.

Key Points

• Carbamazepine is an anticonvulsant medication that works by blocking sodium channels in neurons, stabilizing hyperexcited nerve membranes and preventing repetitive neuronal firing.
• The most common side effects of carbamazepine include drowsiness, headache, and dizziness.
• Blood monitoring is necessary during treatment as carbamazepine can cause serious adverse effects, including blood disorders, liver problems, and severe skin reactions like Stevens-Johnson syndrome.
• Carbamazepine induces liver enzymes, potentially decreasing the effectiveness of other medications, and patients should be aware of potential interactions with other drugs.
• For patients with neuropathic corneal pain, carbamazepine can be started at 200 mg at night and gradually increased by 200 mg every 7 days to a final dose of 400–1200 mg, divided in 2–3 doses per day 1.

Dosage and Administration

• The typical starting dose for adults with epilepsy is 200mg twice daily, gradually increasing to a maintenance dose of 800-1200mg daily divided into 2-3 doses.
• For trigeminal neuralgia, treatment usually begins at 100mg twice daily, increasing gradually to 200mg 3-4 times daily as needed.
• The initial dosage of carbamazepine for paroxysmal kinesigenic dyskinesia treatment is recommended to be 50 mg and can be adjusted according to the practical effect 1.

Special Considerations

• HLA-B*15:02 screening should be implemented before initiating carbamazepine treatment to reduce the risk of adverse cutaneous reactions, particularly in the Han Chinese population 1.
• Patients who harbor HLA-B*15:02 or cannot tolerate the dizziness or drowsiness of carbamazepine may be considered for alternative treatments, such as lamotrigine, topiramate, or phenytoin sodium 1.

From the FDA Drug Label

The FDA drug label does not answer the question.

From the Research

Carbamazepine Overview

• Carbamazepine (CBZ) has a long history of successful use in epilepsy and bipolar disorder, with a well-characterised safety profile 2.
• The most frequent adverse events associated with CBZ are somnolence, fatigue, dizziness, and headache, while rare serious adverse effects include agranulocytosis, aplastic anaemia, Stevens-Johnson syndrome, and toxic epidermal necrolysis 2.

Efficacy in Bipolar Disorder

• CBZ has stronger efficacy in treating acute mania than depression, and better protection against manic than depressive relapses 3.
• CBZ and oxcarbazepine match Class A criteria for the treatment of bipolar disorder, meaning acute antimanic efficacy, prevention of manic relapses, and not causing or worsening depression 3.
• CBZ is similarly effective to valproate in the treatment of acute mania, but may be better suited for long-term therapy due to its adverse event profile 4.

Use in Comorbid Conditions

• CBZ has robust efficacy in the management of comorbid bipolar disorder and chronic pain, although more studies are needed to confirm its effectiveness in this population 5.
• CBZ remains a first-line option or second-line alternative for the treatment of focal-onset epilepsy and primary generalized tonic-clonic seizures, due to its good compromise between cost, availability, and effectiveness 6.

Safety and Tolerability

• CBZ has a safety profile that is well characterised, with proper monitoring and careful titration of the extended-release formulation allowing for successful use in psychiatric patients 2.
• Tolerability issues and drug-drug interactions need to be kept in mind, especially with CBZ, although it may be better suited for long-term therapy due to its adverse event profile 3, 4.