Serious hepatotoxicity following use of isoniazid preventive therapy in HIV patients in Eritrea.

WHO information note indicates that isoniazid preventive therapy (IPT) is generally safe with little risk of hepatotoxicity. However, when the policy of IPT for HIV patients was introduced in Eritrea, frequent IPT-associated hepatotoxicity and fatality have been reported to the Pharmacovigilance Centre. The aim of the study is to assess the causal association of IPT and hepatotoxicity and identify possible risk factors in patients on Highly Active Anti-retroviral Therapy (HAART). This is a case series assessment of spontaneously reported cases to the Eritrean Pharmacovigilance Centre. Data extracted from VigiFlow (reported between 2014 and 2016) were exported to excel spread sheet for descriptive and qualitative analysis. Naranjo probability scale and Austin Bradford-Hill criteria were used to assess causality. The P-Method was used to assess preventability. A total of 31 of cases of hepatotoxicity related to IPT were retrieved. Majority (80.6%) of the cases were marked as "serious" due to life-threatening situation (n = 15), hospitalization (n = 6), and death (n = 4). Baseline liver function test was normal in 61.3% and hepatitis B and C infections were ruled out in 77.4%. IPT was discontinued in 26 cases and reaction abated in 22 of them. Causality assessment using Austin Bradford-Hill criteria found that the association was strong, consistent and specific with a plausible temporal relationship and biological mechanism. IPT-associated hepatotoxicity that led to treatment interruption and death was observed in patients on HAART in Eritrea. Hence, close laboratory monitoring of patients is recommended to minimize the risk.