FDA Approves IV Formulation of Carbamazepine for Seizures

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The drug is the first and only IV formulation of the antiepileptic carbamazepine.

The US Federal Drug Administration (FDA) has approved the first intravenous formulation of carbamazepine for adults with certain seizure types. The drug, Carnexiv™, is intended for temporary situations in which oral administration is not feasible.

Developed by Lundbeck, the drug is approved for short-term (7 days or less) administration in adults with partial seizures with complex symptomatology, generalized tonic-clonic seizures, and mixed seizure patterns.

“Carbamazepine is very difficult to make as an aqueous-based injectable formulation, which means that doctors have not had an IV formulation of the drug available when needed,” James Cloyd, PharmD, director of the Center for Orphan Drug Research at the University of Minnesota College of Pharmacy, said in a statement. “This approval is the result of years of work to create a novel and stable injection formulation to support patients who need an alternative to oral carbamazepine.”

When switching from oral carbamazepine to the IV formulation, the total daily dosage of Carnexiv should be 70% of the total daily dosage of oral carbamazepine. It should be administered in 4 equal parts during 30-minute infusions every 6 hours. Once treatment with Carnexiv is stopped, patients should return to their typical oral dosage and frequency as soon as possible.

As with oral carbamazepine, serious and sometimes fatal dermatologic reactions may occur with use of Carnexiv; in such cases, treatment should be discontinued. Patients who are genetically at risk, particularly those of Asian descent, should avoid taking Carnexiv. Other adverse events include aplastic anemia and agranulocytosis. Carnexiv is contra-indicated for patients with bone marrow depression and a known sensitivity to carbamazepine or tricyclic antidepressants; concomitant use of certain non-nucleoside reverse transcriptase inhibitors; and use of monoamine oxidase inhibitors within 14 days of carbamazepine treatment. Carnexiv should also not be used in patients with moderate-to-severe renal impairment.

Additional adverse reactions include dizziness, somnolence, blurred vision, diplopia, headache, and infusion-site reaction and/or pain.

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FDA Approves Carnexiv™ (carbamazepine) injection as Intravenous Short-Term Replacement Therapy for Certain Seizure Types [news release]. Deerfield, Ill: Lundbeck newsroom; October 7, 2016.