Drug-induced liver disease in 2003

Causality assessment in hepatotoxicity by drugs and dietary supplements

Structured causality assessment of hepatotoxicity by drugs and dietary supplements (DDS) is a major clinical challenge, since temporal associations as the sole criteria for a valid evaluation are not acceptable. Initially, a clear intuition for an ad hoc evaluation is necessary, but only provisional, and must be followed by a diagnostic algorithm using a pretest, main test and post test. The evaluation is based on a variety of items such as latency period, course of alanine aminotransferase and alkaline phosphatase after DDS discontinuation, risk factors, co-medication, previous information on hepatotoxicity of the DDS, response to rechallenge, and exclusion of other diseases. It is essential that practising and hospital physicians as well as other key health professionals, such as pharmacists, gather all information required for a sound causality assessment, obviating major discussions by expert panels, manufacturers and health agencies in face of scanty and fragmentary data. Because pharmacogenetic alterations may trigger metabolic hepatotoxicity by a few DDS, levels in plasma and urine should be measured and may be helpful for diagnosis. Concomitant genotyping of cytochrome P450 and other enzymes may also be useful in future to minimize the risk of unwanted side-effects, including toxic liver disease elicited by DDS.

Incidence of statin hepatotoxicity in patients with hepatitis C

BACKGROUND AND AIMS

Statins are considered contraindicated in patients with chronic liver disease. Our objective was to determine the risk of developing hepatotoxicity from statin therapy in hyperlipidemic patients with hepatitis C.

METHODS

Changes in liver biochemistry values within 12 months compared with baseline were determined in 3 cohorts matched for age, sex, and body mass index: (I) 166 anti-hepatitis C virus (HCV)-positive hyperlipidemic veterans who were initiated on statin therapy; (II) 332 anti-HCV-positive veterans who had not received statin therapy; and (III) 332 anti-HCV-negative hyperlipidemic veterans who were initiated on statin therapy. An increase in liver biochemistry values was defined as mild-moderate or severe as proposed in a previous study on statin hepatotoxicity in a non-hepatitis C population.

RESULTS

In patients with hepatitis C, statin therapy (cohort I) was associated with a higher incidence of mild-moderate liver biochemistry value increases compared with those not on statin therapy (cohort II) (22.9% vs 13.3%, respectively, P = .009), but a lower incidence of severe increases (1.2% vs 6.6%, respectively, P = .015). Among patients started on statin therapy (cohorts I and III), the incidence of mild-moderate liver biochemistry value increases (22.9% vs 16.3%, respectively, P = .094), severe increases (1.2% vs 1%, respectively, P = .874), or discontinuation of statin therapy as a result of hepatotoxicity (21.6% vs 9.2%, respectively, P = .147) were similar in hepatitis C-positive and hepatitis C-negative patients.

CONCLUSIONS

Statin therapy was not associated with a higher risk of severe hepatotoxicity in patients with chronic hepatitis C and appeared safe.

Drug-induced liver disease 2004

PURPOSE OF REVIEW

To summarize the salient reviews, studies and case reports and series that dealt with clinical, pathological, methodological, and epidemiological descriptions of drug-induced liver disease in the calendar year 2004.

RECENT FINDINGS

While no new causes of drug-induced liver injury were reported for 2004, several new reports of previously recognized hepatotoxins, including herbal products, were published. These include the antiretroviral drugs for HIV and agents to manage tuberculosis. Acetaminophen (APAP) retained its preeminent position as the leading cause of drug-induced acute liver failure, currently accounting for nearly 50% of cases according to the latest figures from the U.S. Acute Liver Failure Study Group. Not surprisingly, APAP also heads the list of drugs and toxins leading to liver transplantation for acute hepatic failure. Efforts to reduce the number of cases of intentional APAP poisonings by restricting the number of tablets sold at any one time in the UK are ongoing, but the success of the program may be lessening, as was pointed out this year. The use of potentially hepatotoxic medications in patients with underlying liver disease was examined with the statins, and they emerged as a safe class for use in this setting.

SUMMARY

Given the apparent increasing incidence of acute liver failure attributable to APAP in the US, additional efforts are still needed to better define the risks associated with its use and to further reduce the incidence of severe liver injury from this widely used agent.