Hypersensitivity and dose related side effects of phenytoin mimicking critical illness

Abstract

Objective: To describe phenytoin-induced rare hypersensitivity and dose related reactions, emphasizing the importance of early omission of drug to achieve clinical improvement. Design: Case series and review of literature. Setting: Tertiary level medical intensive care unit. Patients: Three cases, two of whom had hypersensitivity reactions and the third had drug-induced dyskinesia. Intervention: Omission of phenytoin and corticosteroid therapy in two cases. Results: Improvement and discharge. Conclusion: A high index of suspicion of drug-induced complications is necessary especially when multiple drugs are being administered to critically ill patients.

Anticonvulsant hypersensitivity syndrome after phenytoin administration in an adolescent patient: a case report and review of literature

“…While, several tests used to confirm the diagnosis of AHS, like patch testing and lymphocytes transformation test which is used to assess the drug reactive T cells [18], AHS remains a diagnosis of exclusion which is largely achieved by the following: clinical features, absence of a septic focus and the probable response to steroid treatment [7]. Table 3 summarizes the clinical features of AHS.…”

“…Although reduced immunoglobulins (IgA, IgM, IgG) is noticed at the onset of the hypersensitivity response, several weeks after the suspension of the anti-epileptic medication the immunoglobulins level start to increase [ 11 , 18 , 24 ]. While, several tests used to confirm the diagnosis of AHS, like patch testing and lymphocytes transformation test which is used to assess the drug reactive T cells [ 18 ], AHS remains a diagnosis of exclusion which is largely achieved by the following: clinical features, absence of a septic focus and the probable response to steroid treatment [ 7 ]. Table 3 summarizes the clinical features of AHS.…”

“…This hypersensitivity reaction primarily associated with phenytoin, carbamazepine, lamotrigine, and phenobarbital administration [ 6 ]. In most cases, the condition appears within 2 weeks to 2 months after exposure to the anti-epileptic medication [ 7 ]. It is estimated to occur in one every 1000–10,000 exposures [ 8 ].…”

“…Because many recent studies conclude that women especially fertile women are more prone to this drug reaction, hormonal phenomenon might be included in the pathogenesis of AHS [ 9 ]. The majority of the reported cases has been in african american patients [ 7 ]. It is worth mentioning that AHS has an autosomal dominant inheritance pattern; with increased susceptibility between siblings of affected patients [ 10 ].…”

Hypersensitivity reaction associated with phenytoin

“…Phenytoin presents dose-related adverse drug reactions (ADRs) due to its narrow therapeutic index and variability among individual patients. [ 2 ] Manifestations of any type of ADRs due to phenytoin are followed by switching to other nonreacting AEDs. [ 3 4 5 ] Hypersensitivity reactions with phenytoin are estimated somewhere between 1 in 1000 worldwide, but the exact incidence is unknown.…”