Continuity of Care With IV Carbamazepine: A Case Report for Maintaining Treatment

Objective: To describe a case report that illustrates the importance of maintaining CBZ treatment. Background: Since its approval in the mid-1970s, oral CBZ has been widely used by patients who initiated treatment many years ago, and it continues to be an affordable choice for patients from lower socioeconomic groups and/or those with a high-deductible insurance plan. Though CBZ is a known inducer of cytochrome P450 (CYP) isoenzymes, prescribers may be unaware of the risk of toxicity upon withdrawal. Under circumstances in which oral administration of CBZ is temporarily impracticable, continuity of care with an intravenous CBZ formulation (IV-CBZ) would be preferable in order to maintain seizure control and to avoid possible effects of de-induction. Design/Methods: A case report of carbamazepine (CBZ) de-induction is described. Results: A 51-year old female with a history of seizures, rheumatic heart disease, mitral valvotomy, and uncontrolled symptomatic epilepsy was experiencing 1–2 secondarily generalized seizures/month despite use of phenytoin and carbamazepine; patient was concurrently receiving digoxin and warfarin. Phenytoin was slowly withdrawn and patient was maintained on lamotrigine (150 mg b.i.d.) and CBZ continuous-release formulation (400 mg b.i.d.). Three years later, patient experienced ataxia and was referred by a general practitioner to another hospital, at which time CBZ was withdrawn over several months at an outpatient clinic. Patient died shortly after admission to the emergency department with shock and severe back pain. Cause of death was unrecognized retroperitoneal hemorrhage due to warfarin toxicity secondary to de-induction following CBZ withdrawal. Conclusions: Managing concomitant treatments in CBZ-treated patients can be difficult as altering a stable dosage of CBZ can affect exposure to other medications. The use of IV-CBZ can maintain patients’ stable CBZ treatment when oral administration is impracticable, avoiding untoward and potentially dangerous side effects of CBZ de-induction. Study Supported by: Lundbeck LLC Disclosure: Dr. Brodie has received personal compensation for activities with UCB Pharma, Eisai Ltd, Lundbeck Inc., GW Pharmaceuticals, Bial, GlaxoSmithKline, Sanofi Aventis, and Abbot for grants/research support, honoraria, consulting fees, or speakers bureau. Dr. Klein has received personal compensation for activities with Eisai, Sunovion, and UCB Inc. as a speaker. Dr. Klein has received personal compensation for activities with Lundbeck LLC, Sunovion, and UCB Inc. as an advisory board member. Dr. Klein has received research support from Eisai and Lundbeck LLC. Dr. Sankar has received personal compensation for activities with Lundbeck, Eisai, UCB Pharma, Supernus, Sunovion, Upsher-Smith, and Cyberonics. Dr. Gidal has received personal compensation for activities with UCB, Eisai, and Sunovion for speaking engagements. Dr. Gidal has received personal compensation from UCB, Eisai, Sunovion, Upsher-Smith, Lundbeck LLC, and SK-Bioscience as a consultant. Dr. Tolbert has received personal compensation for activities with Lundbeck LLC.