Cross Hypersensitivity Syndrome between Phenytoin and Carbamazepine.
OBJECTIVE
To evaluate the incidence of cross anticonvulsant hypersensitivity syndrome (AHS) between phenytoin (PHT) and carbamazepine (CBZ) in hospitalized patients.


METHODS
Retrospective chart review about the cross AHS was retrieved from pharmacy adverse drug reaction program from 1998 to 2002 in a 450-bed teaching hospital.


METHODS
AHS was defined as the appearance of at least two symptoms with the first anticonvulsant drug (ACD). Cross AHS was considered if after withdrawal of a first ACD because of hypersensitivity symptoms, a new episode with similar or new symptoms appeared after exposure to a second ACD. The following symptoms were considered- rash, fever, hepatotoxicity, lymphadenopathies or hematological disturbances.


RESULTS
Cross AHS between PHT and CBZ was observed in nine cases (45). After the cross-reaction event, four of them were treated with valproic acid, two with vigabatrin, two with phenobarbital and one with no treatment without developing further AHS.


CONCLUSIONS
AHS is a severe complication of aromatic ACD that can compromise the future choice of therapy. Because of the high incidence of clinical cross-reaction between these two drugs, non-aromatic ACD alternatives, must be considered.
Sierra
Nerea Moyano
NM
Hospital Severo Ochoa, Avda Orellana s/n, 28911, Leganés, Madrid, Spain. nereamoyano@hotmail.com
García
Benito
B
Marco
Javier
J
Plaza
Susana
S
Hidalgo
Francisco
F
Bermejo
Teresa
T
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000927:Anticonvulsants / Q000009:adverse effects*; D002220:Carbamazepine / Q000009:adverse effects*; D002648:Child; D002675:Child, Preschool; D003429:Cross Reactions; D004342:Drug Hypersensitivity / Q000175:diagnosis / Q000201:enzymology / Q000453:epidemiology*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D010672:Phenytoin / Q000009:adverse effects*; D012189:Retrospective Studies
D000927:Anticonvulsants; D002220:Carbamazepine; D010672:Phenytoin