BlackBoxRX
 
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Carbamazepine

Hematological; Serious Dermatologic Reactions and HLA-B*1502 Allele

Hematological

  • Aplastic anemia and agranulocytosis has been reported with use of carbamazepine.
  • Risk 5-8 times greater than general population. However, the overall risk of these reactions in the untreated general population is low. Agranluocytosis: 6 patients/1 million population per year. Aplastic anemia: 2 patients/1 million population per year.
  • Incidence data: Although reports of transient or persistent decreased platelet or white blood cell counts are not uncommon with carbamazepine use, data are not available to esitmate accurately their incidence or outcome.
  • Outcomes: The vast majority of the cases of leukopenia have not progressed to the more serious conditions of aplastic anemia or aganulocytosis.
  • Discontinuation of medication should be considered if any evidence of significant bone marrow depression develops.
  • Because of the very low incidence of agranulocytosis and aplastic anemia the vast majority of minor hematologic changes observed during monitoring are unlikely to signal the development of either event.
  • Perform complete pretreatment blood counts (including platelets and possibly reticulocytes and serum iron) and periodic monitoring through therapy. If low or decreased white blood cell count or platelet counts occur, monitor patient closely.

Serious Dermatologic Reactions and HLA-B*1502 Allele

  • Serious and sometimes fatal dermatologic reactions, including toxic epidermal necrolysis (TEN) and Stevens-Johnson Syndrome (SJS), have been reported during treatment with carbamazepine.
  • These reactions are estimated to occur in 1 to 6 per 10,000 new users in countries with mainly caucasian populations, but the risk in some Asian countries is estimated to be about 10 times higher.
  • Studies in patients of Chinese ancestry have found a strong association between the risk of developing SJS/TEN and the presence of HLA-B*1502, an inherited allelic variant of the HLA-B gene. HLA-B*1502 is found almost exclusively in patients with ancestry across broad areas of Asia.
  • Patients with ancestry in genetically at risk populations should be screened for the presence of HLA-B*1502 prior to initiating treatment with carbamazepine.
  • Patients testing positive for the allele should not be treated with carbamazepine unless the benefit clearly outweighs the risk (see WARNINGS and PRECAUTIONS/Laboratory Tests).

MONITORING RECOMMENDATIONS RELATED TO BLACK BOX DATA

Note: The following recommendations are part of the black box warning data.

  • Discontinuation of medication should be considered if any evidence of significant bone marrow depression develops.
  • Because of the very low incidence of agranulocytosis and aplastic anemia the vast majority of minor hematologic changes observed during monitoring are unlikely to signal the development of either event.

Note: The following recommendations are outlined in the Laboratory Test section of the package insert.

  • Perform complete pretreatment blood counts (including platelets and possibly reticulocytes and serum iron) and periodic monitoring through therapy. If low or decreased white blood cell count or platelet counts occur, monitor patient closely.

FDA and Industry Communications

Index to FDA Drug Safety Information

Patient Counseling Information

Medication Guides

Patient Medication Guide - CARBATROL
Patient Medication Guide - EQUETRO ER
Patient Medication Guide - TEGRETOL and TEGRETOL XR

Package Inserts

Carbamazepine

Additional Information

Updated January 2018