Cost minimization of HLA-B*1502 screening before prescribing carbamazepine in Thailand.

BACKGROUND: Carbamazepine (CBZ) is broadly used for the treatment of epilepsy, neuropathic pain and other neurological diseases, owing to its effectiveness and low price. CBZ can induce Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN). There are several studies that found an association between HLA-B*1502 and CBZ-induced SJS/TEN, especially in people of Thai origin. In Thailand the prevalence of HLA-B*1502 was found to be in the range 8.1-14 %. OBJECTIVE: This study aimed to determine if screening for HLA-B*1502 in Thai patients who were to receive CBZ is cost effective. Setting Srinagarind Hospital, Khon Kaen University, Thailand. METHOD: A comparison between treatment cost of CBZ induced SJS/TEN and the HLAB*1502 screening costs in the Thai population. MAIN OUTCOME MEASURE: Comparison of the costs of treatment of CBZ induced SJS/TEN and costs of HLA-B*1502 screening test. Results When persons having the HLA-B*1502 allele receive CBZ, the chance of developing SJS/TEN is as high as 88.1 %, while persons without the HLA-B*1502 allele do not develop SJS/TEN. Therefore, a model was calculated to compare the cost of treatment between HLA-B*1502 testing before giving CBZ and if the patients were not tested for HLAB*1502. It was found that screening 100 patients before giving CBZ would save an amount of 98,549.94 baht per 100 cases of CBZ-prescribed patients. CONCLUSION: The screening for HLA-B*1502 allele before giving carbamazepine is cost effective. The results of the present study may also apply to other populations if the HLA-B*1502 frequency is high enough.