Introduction Voluntary spontaneous reporting system has been used as a major method to report ADRs in Thailand. Efavirenz is in the NNRTI class, combined use with other antiretroviral (ARV) to treat the infection. Efavirenz is metabolised by liver and various adverse drug reactions (ADRs) can be found when used it for long term or with other drugs. Explore the distribution and determinant of ADR associated with ARV in Thai population is not well established but crucial for improve patient care and generate risk minimization in both population and individual level.

Objective The Thai adverse event reports from 2010 to 2014 were reviewed to assess serious adverse events induced by efavirenz.

Methods Thai adverse event reports data were assessed by elimination of duplicated records as well as adjustments to standardise drug names, reports involving efavirenz were analysed. Exposure variables are efavirenz used. Outcome variables are serious ADRs which happened within the study period. Other important variable such as sex, co morbidity, multiple drugs used are evaluated. Hepatitis, exfoliative dermatitis, and Stevens Johnson syndrome were focused on as serious adverse events. Signals in the data were detected by quantitative data mining algorithms, the reporting odds ratio.

Results A total of 1,763 reports related to efavirenz were analysed. The average age were 46.42 years. Two cases were fatal outcome. Significant signals of the adverse events were detected with hepatitis, exfoliative dermatitis and Stevens Johnson syndrome. Drug eruption was also detected.

Conclusions Serious reactions from efavirenz were hepatitis, exfoliative dermatitis and Stevens Johnson syndrome. They made fatal and life threatening outcome. The recommendation is further specific monitoring to reduce serious risk in efavirenz use.

Disclosure of interest statement Serious reactions from efavirenz were hepatitis, exfoliative dermatitis and Stevens Johnson syndrome. They made fatal and life threatening outcome. The recommendation is further specific monitoring to reduce serious risk in efavirenz use.