Learn how Carbamazepine can effectively manage chronic pain through the Carbamazepine Chronic Pain Management Fellowship at Asian Pain Academy.
Indications -
Carbamazepine, approved by the FDA, is indicated for epilepsy, targeting partial seizures (psychomotor, temporal lobe), generalized tonic seizures (grand mal), and mixed seizure patterns. Additionally, it serves as a first-line treatment for trigeminal neuralgia and acute manic/mixed episodes in bipolar I disorder.
Off-label applications include managing refractory schizophrenia, restless leg syndrome, alleviating neuropathic pain.
Carbamazepine Chronic Pain Management Fellowship
Mechanism of Action -
Carbamazepine operates by modulating voltage-gated sodium channels, resulting in the inhibition of action potentials and reduced synaptic transmission. Its mechanism is akin to other anti-convulsant, with an affinity for binding to the alpha subunit of VGSC. The proposed effect is the maintenance of sodium channels in inactivated states, diminishing the number of channels available to open and, consequently, impeding the generation of action potentials. Additionally, carbamazepine interacts with other voltage-gated ion channels, including voltage-gated calcium channels, contributing to its overall neurophysiological impact.
Pharmacokinetics of Carbamazepine -
Carbamazepine exhibits a bioavailability ranging from 75% to 85% following oral administration. The absorption process is influenced by the presence of food, particularly high-fat meals, which enhances the rate of absorption. The primary site of metabolism for carbamazepine is the liver, where the CYP3A4 hepatic enzyme plays a crucial role. This enzyme transforms carbamazepine into its active metabolite, carbamazepine-10,11-epoxide, which, in turn, undergoes further metabolism to its trans-diol form under the action of the enzyme epoxide hydrolase. After a single dose of extended-release formulations, the mean elimination half-life of carbamazepine ranges between 35 to 40 hours, reflecting the duration of time it takes for half of the drug to be eliminated from the body.
Dosage -
Carbamazepine is offered in various formulations, including conventional tablets (100mg, 200mg), extended-release tablets (100 mg, 200 mg, 300 mg, and 400 mg), suspensions, and solutions. Notably, extended-release tablets should not be crushed or chewed. Tegretol and Tegretol XR are recommended to be taken with food. Initial dosages involve 200 mg once or twice daily for adults and 100 mg twice daily for children under 12, gradually increasing to reach a minimum effective level.
Adverse Effects of Carbamazepine -
Carbamazepine commonly induces mild side effects such as dizziness, drowsiness, ataxia, nausea, and vomiting.
However, it can lead to severe dermatologic reactions like Steven Johnson syndrome/toxic epidermal necrolysis (SJS/TEN) and hematologic issues such as agranulocytosis and aplastic anemia. Mild and reversible hyponatremia may occur, especially in elderly patients, but early diagnosis ensures successful resolution. Additionally, serious side effects encompass central nervous system depression, hepatotoxicity, confusion, renal toxicity, and the potential for suicidal ideation. Vigilance for these effects is essential for safe and effective carbamazepine use.
About the author -
Dr Debjyoti Dutta is a renowned pain physician and author who works at Samobathi Pain Clinic and Fortis Hospital in Kolkata. He is also the registrar of the Indian Academy of Pain Medicine. He has expertise in musculoskeletal ultrasound and interventional pain techniques. He has written influential books such as “Musculoskeletal Ultrasound in Pain Medicine” and “Clinical Methods in Pain Medicine,” which provide valuable knowledge on pain management. He is also a faculty member of the Asian Pain Academy Courses, where he trains pain fellows in Kolkata, India, and helps them advance their skills and careers.
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