Drug-induced liver injury

Progress in the understanding of susceptibility factors to drug-induced liver injury (DILI) and outcome predictability are hampered by the lack of systematic programs to detect bona fide cases. A cooperative network was created in 1994 in Spain to identify all suspicions of DILI following a prospective structured report form. The liver damage was characterized according to hepatocellular, cholestatic, and mixed laboratory criteria and to histologic criteria when available. Further evaluation of causality assessment was centrally performed. Since April 1994 to August 2004, 461 out of 570 submitted cases, involving 505 drugs, were deemed to be related to DILI. The antiinfective group of drugs was the more frequently incriminated, amoxicillin-clavulanate accounting for the 12.8% of the whole series. The hepatocellular pattern of damage was the most common (58%), was inversely correlated with age (P < .0001), and had the worst outcome (Cox regression, P < .034). Indeed, the incidence of liver transplantation and death in this group was 11.7% if patients had jaundice at presentation, whereas the corresponding figure was 3.8% in nonjaundiced patients (P < .04). Factors associated with the development of fulminant hepatic failure were female sex (OR = 25; 95% CI: 4.1-151; P < .0001), hepatocellular damage (OR = 7.9; 95% CI: 1.6-37; P < .009), and higher baseline plasma bilirubin value (OR = 1.15; 95% CI: 1.09-1.22; P < .0001). Patients with drug-induced hepatocellular jaundice have 11.7% chance of progressing to death or transplantation. Amoxicillin-clavulanate stands out as the most common drug related to DILI.

The occurrence of idiosyncratic drug hepatotoxicity is a major problem in all phases of clinical drug development and the most frequent cause of post-marketing warnings and withdrawals. This review examines the clinical signatures of this problem, signals predictive of its occurrence (particularly of more frequent, reversible, low-grade injury) and the role of monitoring in prevention by examining several recent examples (for example, troglitazone). In addition, the failure of preclinical toxicology to predict idiosyncratic reactions, and what can be done to improve this problem, is discussed. Finally, our current understanding of the pathophysiology of experimental drug hepatotoxicity is examined, focusing on acetaminophen, particularly with respect to the role of the innate immune system and control of cell-death pathways, which might provide targets for exploration and identification of risk factors and mechanisms in humans.

The incidence of hepatic adverse drug reactions (ADRs) remains unknown in the general population. The goal of this population-based study was to assess the incidence and seriousness of hepatic ADRs. All new cases of symptomatic drug-induced hepatic injuries were collected by 139 trained physicians (general practitioners [GPs] and specialists) between November 1997 and November 2000 in an area containing 81,301 inhabitants who could not go elsewhere for medical care. Over 3 years, 34 cases of hepatic ADRs were collected, 82% of them in outpatients. Global crude annual incidence rate was 13.9 +/- 2.4 per 100,000 inhabitants; corresponding standardized annual global rate was 8.1 +/- 1.5. There was no difference between urban and rural areas. Standardized incidence female/male ratio was 0.86 (0.26-2.90) until 49 years of age and 2.62 (1.00-6.92) after this age. Diagnosis was carried out by GPs in half of the cases. The outcome was recovery for 32 patients and death for 2. The main drugs implicated were anti-infectious, psychotropic, hypolipidemic agents, and nonsteroidal anti-inflammatory drugs (NSAIDs). Our results suggest that the number of hepatic ADRs in the French population would be 16 times greater than the number noted by spontaneous reporting to French regulatory authorities. In conclusion, the incidence and seriousness of drug-induced hepatitis are largely underestimated in the general population. These results may be useful for further evaluation of drug-induced hepatotoxicity.