Ticlopidine-induced prolonged cholestasis: a case report

Ticlopidine-Induced Cholestatic Inflammatory Hepatitis: New Insights into Pathogenetic Mechanisms of Drug-Related Hepatotoxicity

In immune-induced liver damage the reactive metabolites may covalently bind or alter liver proteins such as cytochrome P450 enzymes, which leads to activation of the immune system. Ticlopidine is an inhibitor of CYP2C19 human liver cytochrome. We attempted to analyse the role of cytochrome CYP2C19 genetic polymorphism in the development of ticlopidine-induced cholestatic hepatitis and relate it with the specific immune reactivity to ticlopidine, different cytokine profiles and induction of necrosis and apoptosis within the liver tissue. Three patients with cholestatic hepatitis with ticlopidine-related liver injury, 3 patients with obstructive jaundice due to choledocholithiasis, 3 patients treated with ticlopidine without liver damage and 10 healthy individuals were studied. Genotyping for the following genotypes CYP2C19 (CYP2C19*1–3) were tested after polymerase chain reaction (PCR) by restriction fragment length polymorphism (RFLP) with Sma I and BamH I enzymes. The T cell reactivity to ticlopidine was analysed by T cell proliferation assay in PBMC against ticlopidine, tetanus toxoid antigen and phytohemagglutinin on days 0, 90, 150 and 210 after therapy withdrawal. The serum levels of INF-γ, IL-2, IL-4, IL-10, TNF-α, sFas and sFasL were measured by ELISA at the same time points. Apoptosis was analysed by TUNEL assay. All patients with cholestatic hepatitis had “slow metabolizers” genotypes in contrast to other groups. The T cell reactivity to ticlopidine was present only in all the cholestatic hepatitis patients together with substantial decrease in levels of INF-γ, IL-2 and TNF-α during all of the follow-up period. Cholestatic hepatitis patients had high apoptotic index in TUNEL assay. The genetic polymorphism of the cytochrome CYP2C19 gene is directly responsible for the susceptibility to the ticlopidine-induced liver damage. Th1 type of immune reactivity plays the key role in the pathogenesis of drug-induced hepatotoxicity.

[A case of ticlopidine induced acute cholestatic hepatitis and pure red cell aplasia]

Ticlopidine inhibits platelet aggregation and provides beneficial secondary prevention of cerebrovascular and coronary artery disease. Frequently reported adverse effects of ticlopidine include diarrhea, nausea, and rash. However, to our knowledge, there are only a few published reports of the simultaneous occurrence of cholestatic hepatitis and pure red cell aplasia. Here we report a patient with simultaneous severe cholestatic hepatitis and pure red cell aplasia associated with ticlopidine. Although these adverse effects are rare, periodic hematological and liver function tests are recommended after starting ticlopidine.

Drug- and chemical-induced cholestasis

Cholestasis caused by medicinal and chemical agents is an increasingly well-recognized cause of liver disease. Clinical drug-induced cholestatic syndromes producing jaundice and bile duct injury can mimic extrahepatic biliary obstruction, primary biliary cirrhosis, and sclerosing cholangitis, among others. This article updates the various forms of drug-induced cholestasis, focusing on the clinicopathologic features of this form of hepatic injury and on the known or putative mechanisms by which drugs and chemicals lead to cholestasis.

Hepatotoxicity associated with non-steroidal anti-inflammatory drugs

NSAIDs are one of most frequently prescribed agents in clinical practice. Whereas hepatotoxicity is a rare complication of most NSAIDs (typically 1 to 10 per 100,000 persons exposed), the high level of usage means that these drugs cause liver disease. Because of their divergent chemical structures, the mechanisms and clinicopathological manifestations of hepatotoxicity vary widely. The reactive metabolite syndrome, in which serious rash, eosinophilia, and other forms of tissue injury are common, may be incited by several NSAIDs, including newer agents. Women, people aged more than 50 years, and for some drugs, the type of arthritis, may be risk factors for drug-induced liver injury. The spectrum of NSAID-drug related hepatotoxicity continues to expand, with reports of interactive toxicity in adults with hepatitis C and recognition of rare cases of liver disease associated with non-selective, selective, and preferential COX-2 inhibitors. Better outcomes require people taking NSAIDs to be aware of possible drug reactions involving the liver, and prescribers should be vigilant for early symptoms of hepatotoxicity so that incriminated agents are discontinued promptly.

Drug-induced cholestasis

Drugs may cause several overlapping syndromes of cholestasis, the pathophysiological syndrome resulting from impaired bile flow. These reactions comprise approximately 17% of all hepatic adverse drug reactions (ADRs) and they may be severe. Causes of 'pure' (bland) cholestasis include oestrogens and anabolic steroids; rarer associations are with antimicrobials and NSAIDs. 'Cholestatic hepatitis' is a common drug reaction in which liver injury and inflammation cause significant elevation of serum alanine aminotransferase (ALT) as well as cholestasis. Chlorpromazine and ketoconazole are classic examples, but it is now exemplified by amoxycillin-clavulanate and other oxy-penicillins. Chronic cholestasis results from small bile duct injury leading to the vanishing bile duct syndrome (VBDS), a disorder mimicking primary biliary cirrhosis, or from injury to larger bile ducts causing secondary sclerosing cholangitis. Whilst there is increasing evidence of a genetic predisposition to cholestatic drug reactions, there are currently no pretreatment tests to predict drug safety. Prevention of severe reactions therefore relies on early detection of liver injury and prompt drug withdrawal. Symptomatic management includes relief of pruritus and correction of fat-soluble vitamin deficiency. In small cohort studies, ursodeoxycholic acid (UDCA) arrested progressive cholestasis in two-thirds of cases, but evidence for use of corticosteroids is anecdotal. This review considers diagnosis, pathogenesis, prevention and management of drug-induced cholestasis, with particular reference to frequently- and newly-described causes.

A new Poisson and Bayesian-based method to assign risk and causality in patients with suspected hepatic adverse drug reactions: a report of two new cases of ticlopidine-induced hepatotoxicity

OBJECTIVE

The diagnosis of drug-induced hepatotoxicity is based on circumstantial evidence and is often inaccurate. We have designed a method based on published data to assign causality to suspected cases of drug-induced hepatotoxicity.

DESIGN

Forty-seven published cases of ticlopidine-induced hepatotoxicity were identified by a Medline-based literature search. Data regarding abnormal liver function in patients receiving ticlopidine were obtained from the only published placebo-ticlopidine clinical trial (the Canadian American Ticlopidine Study; CATS). Thus, we calculated the maximum number of expected hepatotoxicity cases in patients exposed to ticlopidine and those not exposed to the drug by means of the Poisson distribution. The calculated odds ratio was used as a prior odd for subsequent quantification, using a Bayesian-based approach, of individual ticlopidine-induced hepatotoxicity likelihood. Concretely, the prior odd is modified by several separate likelihood ratios: age; sex; AST level; ALT level; alkaline phosphatase level; total bilirubin level; latent period of adverse reaction appearance; and period of remission of adverse reaction. This methodology was applied to two new cases of suspected ticlopidine-induced hepatotoxicity.

RESULTS

The prior probability of ticlopidine-induced hepatotoxicity derived from CATS data is 61.29%. This is in contrast with the 28.83% incidence rate of drug-induced liver alterations in the general population. Alkaline phosphatase levels and total bilirubin levels were six times the normal values among individuals with ticlopidine-induced hepatotoxicity than in the general population. They were the most relevant likelihood ratios of the Bayesian model to establish a high level of causality relationship between a hepatotoxicity event and ticlopidine use.

CONCLUSIONS

The proposed method, which links information from clinical trials with the profile of clinical hepatotoxicity of a drug defined from published cases reported after a drug is marketed, can be a useful tool for drug postmarketing surveillance research.

Cholestatic syndromes

Continued advances in the field of liver cell biology and molecular biology have provided further insights into the normal physiology of bile secretion and the pathogenesis and therapy for cholestatic syndromes. Important new data have also been published about pathogenesis, clinical features, and treatment of primary biliary cirrhosis, primary sclerosing cholangitis, drug-induced cholestasis, and cholestatic syndromes caused by viral infections.