1. The effects of nilutamide (an anti-androgen with a hydantoin moiety) on the 4-hydroxylation of mephenytoin were studied in rat liver microsomes. Nilutamide, at a concentration expected in human liver (100 microM) during prolonged administration of nilutamide, inhibited by 40% mephenytoin (0.3 mM) 4-hydroxylase activity in liver microsomes from untreated male rats, but not in microsomes from untreated female rats, or in microsomes from dexamethasone-treated male or female rats. 2. Administration to male rats of nilutamide, in doses (20 mg/kg i.p. twice daily) known to reproduce plasma concentrations observed in human therapeutics, decreased by 60% the 24 h urinary excretion of 4-hydroxymephenytoin after administration of mephenytoin (15 mg/kg oral). 3. Nilutamide (100 microM) markedly inhibited mephenytoin 4-hydroxylase activity in human liver microsomes. Inhibition kinetics were consistent with mixed inhibition. It is concluded that nilutamide inhibits mephenytoin 4-hydroxylase activity in untreated male rats and in human liver microsomes. It is suggested that inhibition is likely to occur in vivo in humans receiving therapeutic doses of nilutamide.

Androgen Antagonists↗

PubMed1991

[Atrium-related hepatitis. Report of four cases].

Four patients developed acute hepatitis after receiving Atrium, an association of phenobarbital, febarbamate and difebarbomate, for the treatment of tremor or for the prevention of alcohol withdrawal symptoms. Hepatitis occurred 1 to 3 months after treatment. Asthenia was the unique clinical manifestation. Marked increase in serum aminotransferases and gamma-glutamyltranspeptidase levels were the main biological features. Histological examination showed liver cell necrosis in two cases, prominent in the centrolobular area in one case. There was no case of hepatic failure. Atrium withdrawal was followed by complete recovery within 6 to 12 weeks. The mechanism of Atrium hepatotoxicity remains unknown.

Aged↗

PubMed1991

[Late discovery of drug-related hepatotoxicity].

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Chemical and Drug Induced Liver Injury↗

PubMed1991

Pharmacogenetics of human erythrocyte thiopurine methyltransferase activity in a French population.

1. A genetic polymorphism in human erythrocyte thiopurine methyltransferase activity (RBC TPMT) resulting in a trimodal phenotypic distribution has been demonstrated both in a North American population and in British children. 2. We studied whether such a polymorphism may be also present in a white French population by testing RBC TPMT activity in 303 randomly selected blood donors. 3. We found a large inter-individual variation in RBC TPMT activity which ranged from 2 to 40 nmol ml-1 packed RBC h-1, with a mean value of 15.4 +/- 7.0 nmol ml-1 packed RBC h-1. The enzyme activity was not significantly influenced by the sex and age of the subjects. 4. In our population sample, we found no subject with undetectable enzyme activity. However, the probit plot of the log RBC TPMT activity showed a highly significant change in slope at a TPMT activity of 7.5 nmol ml-1 packed RBC h-1. Thirty four subjects (11% of our population) had TPMT activities below 7.5 nmol ml-1 packed RBC h-1. 5. These data are consistent with the view that the genetic polymorphism of TPMT activity described in populations from North America and the United Kingdom is also present in a French population, with about 89% of subjects exhibiting a high activity and 11% an intermediate activity.

Adult↗

PubMed1991

[Severe ischemic hepatitis after taking cibenzoline].

The authors report the case of a 77 year old man suffering from chronic congestive heart failure, who presented a severe hepatic failure. Since 9 days the patient was treated by cibenzoline for serious ventricular arythmias. Hepatic failure was not due to drug hepatotoxicity but to an indirect effect of cibenzoline diminishing cardiac output. Arguments for ischaemic hepatitis and also two mechanisms of hepatic involvement in cardiac diseases are developed. In most cases association of two mechanisms, vascular stasis and low cardiac output is necessary to create hypoxic hepatitis.

Aged↗

PubMed1991

[A new case of simvastatin-induced acute pancreatitis].

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Acute Disease↗

PubMed1990

Metabolic activation of the new tricyclic antidepressant tianeptine by human liver cytochrome P450.

Incubation of [14C]tianeptine (0.5 mM) with human liver microsomes and a NADPH-generating system resulted in the in vitro covalent binding of a tianeptine metabolite to microsomal proteins. This covalent binding required oxygen and NADPH. It was decreased by piperonyl butoxide (4 mM) by 81%, and SKF 525-A (4 mM) by 87%, two relatively non-specific inhibitors of cytochrome P450, and by glutathione (4 mM) by 70%, a nucleophile. Covalent binding was decreased by 54% in the presence of troleandomycin (0.1 mM), a specific inhibitor of the glucocorticoid-inducible cytochrome P450 IIIA3, but remained unchanged in the presence of quinidine (0.1 mM) or dextromethorphan (0.1 mM), two inhibitors of cytochrome P450 IID6. Preincubation with IgG antibodies directed against cytochrome P450 IIIA3 decreased covalent binding by 65% whereas either preimmune IgG or IgG antibodies directed against P450 IA1, an isoenzyme inducible by polycyclic aromatic compounds, exhibited no significant inhibitory effect. We conclude that tianeptine is activated by human liver cytochrome P450 into a reactive metabolite. This activation is mediated in part by glucocorticoid-inducible isoenzymes but not by P450 IID6 (the isoenzyme which oxidizes debrisoquine) nor by P450 IA1 (an isoenzyme inducible by polycyclic aromatic compounds). The predictive value of this study regarding possible idiosyncratic and immunoallergic reactions in humans remains unknown.

Antidepressive Agents, Tricyclic↗

PubMed1990

Mechanism for the protective effects of silymarin against carbon tetrachloride-induced lipid peroxidation and hepatotoxicity in mice. Evidence that silymarin acts both as an inhibitor of metabolic activation and as a chain-breaking antioxidant.

Administration of silymarin (800 mg/kg i.p.) 30 min before carbon tetrachloride (18 microL/kg i.p.) did not modify total hepatic levels of CCl4 and metabolites in mice, but decreased by 40% the in vivo covalent binding of CCl4 metabolites to hepatic lipids at 2 hr. This pretreatment decreased by 60% the exhalation of ethane during the first hour after CCl4, and decreased by 50% the incidence of liver cell necrosis. In vitro, silymarin (800 micrograms/mL) decreased by 50 to 70% various monooxygenase activities, and decreased by 20% the covalent binding of CCl4 metabolites to microsomal proteins. Silymarin (800 micrograms/mL) decreased by 70% in vitro lipid peroxidation mediated by CCl4 metabolites, and decreased by 90% peroxidation mediated by NADPH alone. Silibinin, one of the three isomers composing silymarin, also decreased carbon tetrachloride-induced lipid peroxidation; this effect, however, was less than that of silymarin in vitro, and was more transient in vivo. Pretreatment with silibinin (800 mg/kg i.p.) 30 min before CCl4 (18 microL/kg i.p.) did not improve SGPT activity or liver histology at 24 hr. We conclude that silymarin prevents carbon tetrachloride-induced lipid peroxidation and hepatotoxicity in mice, firstly, by decreasing the metabolic activation of CCl4, and, secondly, by acting as a chain-breaking antioxidant.

7-Alkoxycoumarin O-Dealkylase↗

PubMed1990

Presence of functional cytochrome P-450 on isolated rat hepatocyte plasma membrane.

Antibodies against cytochrome P-450 are found in some children with autoimmune hepatitis (antiliver/kidney microsome 1) and in patients with ticrynafen hepatitis (antiliver/kidney microsome 2). For an immune reaction against cytochrome P-450 to possibly destroy the hepatocytes, one must assume that cytochrome P-450 is present on the plasma membrane surface of hepatocytes. In a first series of experiments, plasma membranes were prepared with a technique based on the electrostatic attachment of isolated hepatocytes to polyethyleneimine-coated beads. After vortexing, beads were coated with a very pure plasma membrane fraction. Microsomal contamination, judged from the specific activities of glucose-6-phosphatase or NADH-cytochrome c reductase, was less than 1%. Nevertheless, the specific content (per milligram of protein) of CO-binding cytochrome P-450 was 20% of that in microsomes; the specific benzo(a)pyrene hydroxylase activity was 25%, and ethoxycoumarin deethylase 11%. Immunoblots showed the presence of cytochromes P-450 UT-A, UT-H, PB-B, ISF-G and PCN-E, the last three isoenzymes being inducible by, respectively, phenobarbital, 3-methylcholanthrene and dexamethasone. In a second series of experiments, nonpermeabilized isolated hepatocytes from untreated rats were incubated with anticytochrome P-450 antibodies. Immunofluorescence and immunoperoxidase staining confirmed the presence of cytochromes P-450 UT-A, PB-B and ISF-G on the membrane. In a last series of experiments, human antiliver-kidney microsomal 1 antibodies were found to react specifically with rat liver plasma membrane cytochrome P-450 UT-H (IID subfamily). We conclude that several cytochrome P-450 isoenzymes are present, active and inducible on the plasma membrane surface of hepatocytes. It is therefore conceivable that immunization against plasma membrane cytochrome P-450 might lead to the immunological destruction of hepatocytes in some patients.

Animals↗

PubMed1990

Idiopathic biliary ductopenia in adults: a report of five cases.

The clinical and pathological findings of five adult cases of idiopathic nonsyndromatic paucity of interlobular bile ducts are reported. Patients were 18-32 years old at the onset of the disease; four presented with pruritus and/or jaundice and one with bleeding of the esophageal varices. Two patients were siblings. Serum alkaline phosphatase counts ranged from 1 to 16 times the upper normal value, and total bilirubin counts ranged from 0.6 to 8.8 mg/dL (10 to 150 mumol/L). Initial liver biopsy showed portal and periportal fibrosis with cholangiolar proliferation and reduction in the number of interlobular bile ducts. Antimitochondrial antibodies were absent, and bile ducts were normal after opacification. The patients were observed for 3-11 years. Repeated liver biopsies in the five patients showed progression of the lesions, with development of biliary type cirrhosis in four. Two of the four patients with cirrhosis died of hepatic failure 3 and 11 years after onset of the disease. In the two other cases, liver transplantation was performed successfully. These cases suggest that chronic cholestasis with marked ductopenia resembling the nonsyndromatic paucity described in infancy and childhood may reveal itself at an adult age. This disorder, possibly familial, may rapidly progress to severe and even fatal liver disease and could be a new indication for liver transplantation.

Adolescent↗

PubMed1990

Fulminant hepatitis after lisinopril administration.

A case of fulminant hepatitis in a patient taking lisinopril for 5 weeks for arterial hypertension is reported. Jaundice, fever, myalgia, and marked increase in serum aminotransferase activities occurred after 2 weeks of treatment. Continuation of lisinopril administration for 3 weeks after the onset of jaundice was associated with the development of grade III encephalopathy and a marked decrease in prothrombin and proaccelerin levels. This case strongly suggests that lisinopril may induce acute hepatitis and that continuation of the treatment after the onset of jaundice can lead to life-threatening hepatic failure.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed1990

Acute hepatitis after tetrahydroaminoacridine administration for Alzheimer's disease.

Tetrahydroaminoacridine administration has been proposed as a treatment for Alzheimer's disease. Although recent studies have shown that tetrahydroaminoacridine administration can be associated with mild or moderate liver dysfunction, to our knowledge, no case of symptomatic hepatitis with severe liver lesions has heretofore been reported. We describe a patient who developed jaundice after receiving tetrahydroaminoacridine for three weeks. Histologic examination showed extensive hepatocellular necrosis. Tetrahydroaminoacridine withdrawal was followed by the disappearance of jaundice within a few days and complete recovery within 5 weeks. This case shows that tetrahydroaminoacridine administration can induce marked liver cell necrosis resulting in symptomatic acute hepatitis.

Acute Disease↗

PubMed1990

Pentamidine-induced acute pancreatitis in a patient with AIDS.

We report pentamidine-induced acute pancreatitis in a patient with the acquired immunodeficiency syndrome (AIDS). The course of this pancreatitis was prolonged but favorable. Pentamidine was detected in serum as late as one month after discontinuation of therapy. The special pharmacokinetics of this drug may account for the potential severity of pentamidine-induced acute pancreatitis.

Acquired Immunodeficiency Syndrome↗

PubMed1990

Anti-liver endoplasmic reticulum autoantibodies are directed against human cytochrome P-450IA2. A specific marker of dihydralazine-induced hepatitis.

Sera from patients with dihydralazine-induced hepatitis were shown to contain anti-liver microsomal autoantibodies (anti-LM) by indirect immunofluorescence. These anti-LM antibodies were different from anti-liver/kidney microsomes (anti-LKM) 1 or 2 autoantibodies which have been previously described. Sera recognized a single 53,000 = Mr polypeptide in human liver microsomes as judged by immunoblotting, and the target antigen was identified as cytochrome P-450IA2 (P-450IA2) by (a) comparison of immunoblotting patterns with anti-human P-450IA2 and anti-rat P-450IA2 and with five anti-LM sera, and (b) specific immunoinhibition of microsomal ethoxyresorufin and phenacetin O-deethylation activities (both P-450IA2 supported reactions) by anti-LM antibodies. Finally, purified human P-450IA2 was recognized by these anti-LM sera. The anti-LM antibodies are specific for the disease because none of the other antisera tested behaved in the same manner as anti-LM, even those from patients treated with dihydralazine and without hepatic disease. A possible role of P-450IA2 in the metabolism of dihydralazine was suggested by competitive inhibition of ethoxyresorufin-O-deethylase observed in microsomal incubations. Thus, a new example is presented in which a cytochrome P-450 may be a target for autoantibodies in drug-induced hepatitis.

Autoantibodies↗