Hypersensitivity reactions are common
adverse drug reactions (ADRs) associated with
antiepileptics.
Carbamazepine is one of the routinely prescribed drugs for the treatment of
epilepsy and
neuropathic pain. ADRs due to
carbamazepine range from mild maculopapular
rash to severe
anticonvulsant hypersensitivity syndrome (AHS). AHS is the triad of
fever,
rash, and internal organ involvement occurring 1-8 weeks after exposure to an
anticonvulsant (1 in 1,000 to 10,000 exposures). Spontaneously reported three cases of AHS-
drug hypersensitivity reactions induced by
carbamazepine are discussed here. Seven to ten days after starting
therapy, patients developed maculopapular skin rashes,
fever and liver or kidney involvement. The causal relationship between
drug and ADR was found to be 'certain' in one case and 'probable' in other two cases with both WHO-UMC and Naranjo causality assessment scale. All the three cases show category 4a according to Hartwig's severity scale as ADR was the cause for hospital admission. On assessing preventability of ADRs by modified Schumock and Thorntons' scale, one case was falling into category of 'definitely preventable' and other two were 'not preventable'. AHS is rare but serious reaction with
carbamazepine which requires vigilant monitoring by physicians to avoid major consequences.