Anticonvulsants allergic reactions

Pseudoallergic reactions resemble allergic reactions clinically but are not immunologically mediated. Examples include asthma and rashes caused by aspirin and maculopapular erythematous rashes due to ampicillin or amoxicillin in the absence of penicillin hypersensitivity. Few other entities that can initiate this reaction are sulfonamides, anticonvulsants (phenytoin, carbamazepine and phenobarbital), NSAIDs (aspirin, naproxen, nabumetone and keto-profen), antiretroviral agents and cephalosporins [1 ]. 

Of 34 cases of aplastic anemia (mean age 41 years, mean time of felbamate exposure 154 days), 20 occurred in combination with other compounds implicated as a possible cause of aplastic anemia and 5 occurred concurrently with viral infections (7). Although 5 patients were taking felbamate monotherapy, 13 of the 34 suffered from autoimmune disease, and 1 was receiving cytostatic therapy. Past allergic or toxic reactions to other anticonvulsants were reported by 65% of the patients and blood dyscrasias by 45%, while 32% had serological evidence of a previous immune disorder. Eight of nine patients tested had experienced at least one episode of aplastic anemia associated with HLA antigens. 

---