Toxic hepatitis after therapeutic doses of benorylate and D-penicillamine

Long-Term Ingestion of Paracetamol and Liver Disease1

Of 45 patients with chronic active hepatitis, 17 had taken paracetamol before the onset of symptoms. There were no significant differences, however, between the two groups in abnormalities of liver function tests, nor in ease of control after paracetamol withdrawal and institution of immunosuppressive therapy. The patient who had taken more than 5 g/week was studied in greater detail, but after a challenge dose of 1 g paracetamol there was no rise in serum aminotransferases and the pattern of excretion of paracetamol metabolites was normal. A critical review of the previously published reports failed to uncover any convincing evidence that paracetamol is an initiating factor in the development of chronic active hepatitis, although it may, at therapeutic levels, cause a toxic hepatitis in those individuals at risk.

A review of the hepatotoxicity of paracetamol at therapeutic or near-therapeutic dose levels, with particular reference to alcohol abusers

The number of published reports associating hepatotoxicity with paracetamol ingestion at therapeutic or near-therapeutic dose levels is small but is, nevertheless, suggestive of a relationship. There is however, mounting evidence that certain groups of patients, such as alcohol-dependent people, patients receiving enzyme-inducing drugs (particularly anti-convulsant and anti-tuberculosis medications) as well as those with certain infectious diseases, are rendered more susceptible to paracetamol-induced hepatotoxicity. Seventy-four case reports where therapeutic or near-therapeutic doses of paracetamol resulted in hepatic injury are reviewed and factors and mechanisms which might explain this apparently increased vulnerability to damage are discussed.

Metabolic basis for high paracetamol dosage without hepatic injury: a case study

1. Studies of paracetamol metabolism were performed in a 58-year-old female with rheumatoid arthritis who had consumed 15-20 g paracetamol daily for 5 years without developing liver damage and data were compared with results in seven normal volunteers. 2. After a test dose of 2 g paracetamol, the formation of paracetamol sulphate and glucuronide conjugates detected in plasma from the patient was delayed by around 2 h relative to values in normal volunteers and the proportion of sulphate conjugates excreted in urine was 1.5 to 2 times those in normal volunteers (52% vs 26-35% of dose, respectively). The fractional metabolite clearance of paracetamol to glutathione-derived conjugates (0.28 ml min-1 kg-1) in our patient was > 30% lower than in normal females. 3. A combination of slow paracetamol absorption, enhanced detoxication of paracetamol (by sulphation) and reduced metabolism to potentially cytotoxic metabolites may have reduced the risk of liver damage in this patient. The latter may have reflected pharmacogenetic deficiencies in cytochrome P450 isoenzymes persisting despite chronic alcohol consumption (40-60 g per day) or resulted from inhibition of paracetamol activation by concomitant ingestion of aminophylline.

Photolytic degradation of benorylate: effects of the photoproducts on cultured hepatocytes

The photodegradation of benorylate [4'-(acetamido)phenyl-2-acetoxybenzoate], a drug frequently used in rheumatoid arthritis therapy, has been examined under different sets of experimental conditions. Several photoproducts have been isolated and identified on the basis of their IR, NMR, and MS spectra. The most significant photochemical process is the photo-Fries rearrangement of benorylate, leading to 5-acetamido-2'-acetoxy-2-hydroxybenzophenone (1). This compound undergoes a rapid transacylation to the isomeric 5'-acetamido-2'-acetoxy-2-hydroxybenzophenone (2). A primary culture of rat hepatocytes has been used to evaluate the possible toxicity of these two benzophenones, keeping in mind the following criteria: leakage of cytosolic enzymes, attachment index to culture plates, gluconeogenesis from lactate and fructose, glycogen balance, and albumin synthesis. At the concentrations assayed, neither of the two major photoproducts of benorylate (benzophenones 1 and 2) had significant toxic effects on liver cells in culture.

Cholestatic jaundice associated with D-penicillamine therapy

Cholestatic jaundice is a rare complication of penicillamine therapy. We report here a 35-year-old patient who developed fever, a rash and cholestatic jaundice 16 days after commencing treatment with penicillamine for cystinuria. The jaundice subsided slowly after discontinuation of the drug and with prolonged therapy with prednisone. The literature on penicillamine-induced liver injury is reviewed.

Hepatotoxicity associated with use of D-penicillamine in rheumatoid arthritis

Two patients with rheumatoid arthritis developed evidence of hepatotoxicity while receiving D-penicillamine. Both recovered after withdrawal of the drug. These cases and a review of the literature suggested that hepatotoxicity, though rare, should be added to the list of adverse reactions to D-penicillamine.