Suspected clopidogrel-associated hepatitis in a cat

Case summary

Acute hepatitis and liver damage are rare adverse effects of clopidogrel in humans. In veterinary medicine, clopidogrel is mainly prescribed in the treatment of feline patients with cardiomyopathies. Little is known regarding the safety and adverse effects of clopidogrel in this group of patients. The limited number of studies scarcely report adverse effects. In this case report, a 6-year-old male castrated crossbred cat with the hypertrophic cardiomyopathy phenotype had signs of acute hepatitis after 5 weeks of clopidogrel treatment.

Relevance and novel information

Evaluation of the case and review of the literature indicate that acute hepatitis might be a potential adverse effect of clopidogrel in feline patients. Therefore, hepatotoxicity should be taken into consideration when a feline patient shows clinical deterioration after the use of clopidogrel.

Patient characteristics and safety outcomes in new users of ticagrelor and clopidogrel-An observational cohort study in Sweden

PURPOSE

We aimed to describe characteristics of new users of ticagrelor or clopidogrel following a recent coronary event, and to compare incidences of selected safety outcomes.

METHODS

This observational cohort study used data from national Swedish registers. Patients first dispensed ticagrelor or clopidogrel (June 2011-December 2013) were identified from the Prescribed Drug Register and followed until censoring or 31 December 2014. Cohorts were restricted to patients with a recent coronary event-related hospital contact identified in the Patient Register.

RESULTS

The study included 45 987 unique, naïve users of ticagrelor (73% men; mean age 66 years) or clopidogrel (69% men; mean age 69 years). Corresponding to indication, diagnoses before initiation were acute coronary syndrome (93%), myocardial infarction (76%), and percutaneous coronary intervention (69%). The most common medications used in the year before initiation of study therapy were antithrombotic agents (clopidogrel 62%, ticagrelor 43%), mainly low-dose acetylsalicylic acid. Ticagrelor users had a higher incidence (per 1000 person-years) of respiratory bleeding (24.6 [95% confidence interval (CI): 22.1-27.3]; vs clopidogrel users: 14.4 [13.1-15.8]) and dyspnea (25.9 [23.3-28.7]; vs clopidogrel users: 16.8 [15.4-18.4]). Epistaxis accounted for 83-93% of respiratory bleeds. Adjusted analyses found increased risks of gout and acute renal failure with ticagrelor.

CONCLUSIONS

Clopidogrel users were older with a higher prevalence of concomitant medications than ticagrelor users. Our study showed increased incidences of dyspnea and respiratory bleeding (mainly epistaxis) among current ticagrelor users compared with clopidogrel users, and increased risks of gout and acute renal failure after adjustment.

Modulation of miR-26a-5p and miR-15b-5p Exosomal Expression Associated with Clopidogrel-Induced Hepatotoxicity in HepG2 Cells

Clopidogrel is an essential antiplatelet drug used to prevent thrombosis complications associated with atherosclerosis. However, hepatotoxicity is a potential adverse effect related to clopidogrel therapy. Exosome-derived miRNAs may be useful for improved monitoring of drug response and hepatotoxicity risk. In the present study, the expression of several exosomal miRNAs (miR-26a-5p, miR-145-5p, miR-15b-5p, and miR-4701-3p) and cell-derived mRNA targets (PLOD2, SENP5, EIF4G2, HMGA2, STRADB, and TLK1) were evaluated in HepG2 cells treated with clopidogrel (6.25, 12.5, 25, 50, and 100 μM) for 24 and 48 h. Then, clopidogrel cytotoxicity was evaluated by analyzing DNA fragmentation and the cell cycle profile using flow cytometry. Differential expression of exosome-derived miRNAs and cell-derived mRNAs was analyzed by RT-qPCR. Exposure of HepG2 cells to high concentrations of clopidogrel (50 and 100 μM) for 24 h caused significant DNA fragmentation (17.6 and 44.4%, respectively; p < 0.05) and 48 h (26.8 and 48.9%, respectively; p < 0.05), indicating cellular toxicity. Upregulation of miR-26a-5p and downregulation of miR-15b-5p was observed in cells exposed to 100 μM clopidogrel for 24 and 48 h. The miR-26a-5p target mRNAs HMGA2, EIF4G2, STRADB, and SENP5 were downregulated in HepG2 cells following exposure to cytotoxic concentrations of clopidogrel (50 and 100 μM) for 24 h, and HMGA2 levels remained low after 48 h of treatment. TLK1, a target of miR-15b-5p, was downregulated by 50 and 100 μM clopidogrel at 24 h. In conclusion, our results suggest that exposure to high concentrations of clopidogrel modulates the expression of exosomal miR-26a-5p and miR-15b-5p and their target mRNAs in HepG2 cells. Dysregulation of these miRNAs maybe modulate the regulatory pathways involved in clopidogrel-induced liver injury.

A joint allergist/cardiologist classification for thienopyridines hypersensitivity reactions based on their symptomatic patterns and its impact on the management strategies

The role and importance of thienopyridines such as ticlopidine, clopidogrel, and prasugrel is well-established for several indications, ranging from prevention of acute coronary syndromes to percutaneous coronary interventions, where the dual antiplatelet therapy represents the gold standard to avoid denovo coronary stenosis. However, there is a significant cohort of patients with coronary artery disease who may manifest hypersensitivity reactions to thienopyridines. The examination of the various case reports from medical literature leads to identify mainly four clinical patterns of hypersensitivity to thienopyridines which involves more frequently cutaneous, hematologic, and articular tissues, therefore the kind and predominance of clinical symptoms may determine a different clinical approach to overcome or neutralize thienopyridines hypersensitivity.

Clopidogrel-Induced Severe Hepatitis: A Case Report and Literature Review

Clopidogrel is a commonly prescribed antiplatelet agent that carries a rare risk of hepatotoxicity. We describe a case of severe clopidogrel-induced hepatitis with liver biopsy assessment. Prompt recognition and withdrawal of the offending agent are imperative to prevent progression and potentially fatal liver injury.

The mechanism and risk factors of clopidogrel-induced liver injury

CONTEXT AND OBJECTIVE

Clopidogrel (CLP) is a prodrug which is widely used as a platelet aggregation inhibitor. Hepatotoxicity is rare but a potentially serious adverse reaction that is associated with CLP. Thiophene in CLP (the thienopyridine derivative) is a group that is easily oxidated by cytochrome P450 enzymes (CYP450s) to generate reactive metabolites (RMs), it may be implicated in the mechanism of CLP-induced hepatotoxicity. CYP2C19 and CYP2B6 are important CYP450s involved in the metabolism and activation of CLP, and the aim of this study is to investigate whether the metabolites of CYP2C19 and CYP2B6 are associated with the CLP-induced liver injury.

METHOD

Primary rat hepatocytes are applied to evaluate the hepatotoxicity of CLP. Glutathione-depleted mouse model is used to evaluate whether this toxicity of CLP is metabolized by CYP450s. We also used HepG2 cells co-incubated with recombinant CYP2B6 and CYP2C19 enzymes to further assess whether the metabolites of CYP2C19 and CYP2B6 are associated with the CLP-induced hepatocellular toxicity.

RESULT

CLP in high dose (100 μM and 300 μM) showed cytotoxicity in primary rat hepatocytes assay. Administration of CLP with l-buthionine-S, R-sulfoxinine (BSO) for seven days enhanced the liver injury of CLP. The level of ALT, AST and TBIL in plasma increased significantly, and the histopathological results showed the obvious liver injury; Pretreatment of 1-aminobenzotriazole, a nonspecific inhibitor of CYP450s, suppressed CLP-induced hepatotoxicity; CLP showed a dose-dependent toxicity in HepG2/CYP2C19 enzyme and HepG2/CYP2B6 enzyme models.

CONCLUSION

High activities of CYP2C19 and CYP2B6 are the risk factors for hepatocellular toxicity of CLP.

Acute hepatitis associated with clopidogrel: a case report and review of the literature

Drug-induced hepatotoxicity is a common cause of acute hepatitis, and the recognition of the responsible drug may be difficult. We describe a case of clopidogrel-related acute hepatitis. The diagnosis is strongly suggested by an accurate medical history and liver biopsy. Reports about cases of hepatotoxicity due to clopidogrel are increasing in the last few years, after the increased use of this drug. In conclusion, we believe that physicians should carefully consider the risk of drug-induced hepatic injury when clopidogrel is prescribed.

Liver Dysfunction Associated with Intravenous Methylprednisolone Pulse Therapy in Patients with Graves' Orbitopathy

Intravenous methylprednisolone (IVMP) pulse therapy is the first-line treatment for the active phase of moderate to severe Graves' orbitopathy (GO). However, acute and severe liver damage has been reported during and after IVMP therapy. In this retrospective study, we investigated risk factors for liver dysfunction during and after IVMP therapy based on 175 Japanese patients with moderate to severe GO and treated at our center between 2003 and 2011. The results showed that seven patients developed severe liver dysfunction with elevated serum alanine aminotransferase (ALT > 300 U/L). Mild (40-100 U/L) and moderate (100-300 U/L) increases of ALT occurred in 62 patients (35%) and 10 patients (6%), respectively. Liver dysfunction was more frequently observed in males, in patients receiving high-dose methylprednisolone, and patients aged over 50 years. Preexistent viral hepatitis was significantly associated with liver dysfunction (65% in patients positive for hepatitis B core antibody and patients positive for hepatitis C virus antibodies). Our study confirmed the association of liver dysfunction with IVMP during and after treatment. It suggests that, in patients with GO, evaluation of preexisting risk factors-including viral hepatitis-and careful weekly monitoring of liver function during IVMP therapy and monthly thereafter for 12 months are warranted.

Hepatocellular toxicity of clopidogrel: mechanisms and risk factors

Clopidogrel is a prodrug used widely as a platelet aggregation inhibitor. After intestinal absorption, approximately 90% is converted to inactive clopidogrel carboxylate and 10% via a two-step procedure to the active metabolite containing a mercapto group. Hepatotoxicity is a rare but potentially serious adverse reaction associated with clopidogrel. The aim of this study was to find out the mechanisms and susceptibility factors for clopidogrel-associated hepatotoxicity. In primary human hepatocytes, clopidogrel (10 and 100 μM) was cytotoxic only after cytochrome P450 (CYP) induction by rifampicin. Clopidogrel (10 and 100 μM) was also toxic for HepG2 cells expressing human CYP3A4 (HepG2/CYP3A4) and HepG2 cells co-incubated with CYP3A4 supersomes (HepG2/CYP3A4 supersome), but not for wild-type HepG2 cells (HepG2/wt). Clopidogrel (100 μM) decreased the cellular glutathione content in HepG2/CYP3A4 supersome and triggered an oxidative stress reaction (10 and 100 µM) in HepG2/CYP3A4, but not in HepG2/wt. Glutathione depletion significantly increased the cytotoxicity of clopidogrel (10 and 100 µM) in HepG2/CYP3A4 supersome. Co-incubation with 1 μM ketoconazole or 10mM glutathione almost completely prevented the cytotoxic effect of clopidogrel in HepG2/CYP3A4 and HepG2/CYP3A4 supersome. HepG2/CYP3A4 incubated with 100 μM clopidogrel showed mitochondrial damage and cytochrome c release, eventually promoting apoptosis and/or necrosis. In contrast to clopidogrel, clopidogrel carboxylate was not toxic for HepG2/wt or HepG2/CYP3A4 up to 100 µM. In conclusion, clopidogrel incubated with CYP3A4 is associated with the formation of metabolites that are toxic for hepatocytes and can be trapped by glutathione. High CYP3A4 activity and low cellular glutathione stores may be risk factors for clopidogrel-associated hepatocellular toxicity.

Clopidogrel-induced neutropenia after coronary stenting: is cilostazol a good alternative?

Dual antiplatelet therapy with aspirin plus thienopyridines has become the standard treatment of patients undergoing coronary stenting. Clopidogrel has mostly replaced the use of ticlopidine due to its more favourable adverse event profile. However, also the use of clopidogrel is not without side effects. Clopidogrel major adverse events are represented by marrow suppression, manifesting with aplastic anaemia, thrombocytopenia and neutropenia. When clopidogrel toxicity occurs, there are few and unsubstantiated alternative treatments and thus, in these cases, medical decisions may be very difficult. We report a case of clopidogrel-induced bone marrow toxicity manifesting with severe neutropenia in a patient treated with multiple coronary stents and provide suggestions for an alternative treatment.