Cholestatic jaundice associated with D-penicillamine therapy

Drug-induced liver injury: Is it somehow foreseeable?

The classic view on the pathogenesis of drug-induced liver injury is that the so-called parent compounds are made hepatotoxic by metabolism (formation of neo-substances that react abnormally), mainly by cytochromes P-450 (CYP), with further pathways, such as mitochondrial dysfunction and apoptosis, also playing a role. Risk factors for drug-induced liver injury include concomitant hepatic diseases, age and genetic polymorphisms of CYP. However, some susceptibility can today be predicted before drug administration, working on the common substrate, by phenotyping and genotyping studies and by taking in consideration patients’ health status. Physicians should always think of this adverse effect in the absence of other clear hepatic disease. Ethical and legal problems towards operators in the health care system are always matters to consider.

Drug-induced cholestasis

Acute, drug-induced hepatocellular cholestasis (either pure or cholestatic hepatitis) is a common manifestation of drug-induced hepatic injury. The drugs most frequently responsible are hormonal steroids and psychopharmacological agents (in particular phenothiazines and some antidepressants). Cholestasis usually subsides without sequelae in less than six months. Acute, drug-induced ductular cholestasis is uncommon and can resemble biliary tract obstruction. Complete recovery occurs promptly after the withdrawal of the causative drug in most cases. The pathogenetic mechanism may be immunoallergic. Prolonged ductular or ductal cholestasis can follow drug-induced acute hepatitis despite prompt withdrawal of the offending drug. This syndrome, observed mainly with chlorpromazine and uncommonly with twenty other drugs, is characterized by the progressive disappearance of small bile ducts and by manifestations mimicking primary biliary cirrhosis. However, its prognosis appears to be better than that of primary biliary cirrhosis, the condition being reversible in the majority of cases or even subsiding completely. The mechanism is still unknown, but several features suggest some form of autoimmunity. Extrahepatic cholestasis related to sclerosing cholangitis is a frequent and long-term complication of intra-arterial infusion of floxuridine in patients treated for hepatic metastases from colorectal carcinoma. Although it may be reversible, floxuridine-induced sclerosing cholangitis has a poor prognosis and can lead to death in a few patients. The mechanism is probably related to the vascular supply of the common hepatic duct and its relationship to the perfusion territory of floxuridine.

Hepatic and renal tolerability of long-term naproxen treatment in patients with rheumatoid arthritis

Clinical and laboratory assessments of hepatic and renal function in rheumatoid arthritis (RA) patients who received naproxen for up to 6 months during two randomized, double-blind studies comparing naproxen 375 mg twice daily (n = 286) with naproxen 750 mg twice daily (n = 300) were analyzed. Patient groups were segregated by dosage, duration of treatment, and age at entry (less than 65 years v greater than or equal to 65 years), and laboratory measurements of SGOT, SGPT, serum creatinine (Scr), and BUN were examined. Records of individual patients with clinically meaningful abnormalities in laboratory tests or adverse events of hepatic or renal origin were examined in detail. Over the duration of these studies, there were no clinically meaningful changes in mean laboratory values or differences in occurrences of abnormal values among the different patient groups. In both dosage groups, pretreatment incidences of clinically meaningful abnormalities in laboratory tests were similar to those in serial observations during treatment. Six patients who received naproxen 375 mg twice daily and four patients who received naproxen 750 mg twice daily had a hepatic or renal clinical event or distinctly abnormal laboratory value, but only three of these withdrew because of these problems. Occasional transient abnormalities of conventional laboratory tests of hepatic and renal function occurred in some patients during naproxen treatment. Such abnormalities called for careful patient monitoring but generally did not warrant immediate drug withdrawal.

Cystinuria

Cystinuria is an inherited metabolic disease resulting in renal stone formation. An incidence of 1 in 7000 makes it a relatively common genetic disease. The biochemical defect is a carrier protein in the epithelial cells of certain organs. This carrier protein is responsible for the transport of cystine and the dibasic amino acids. Cystine is a poorly soluble compound which precipitates in acid urine and results in renal calculi. Cystine stones account for 1 to 2% of all renal calculi. Homozygotes are detected by the high concentration of cystine in their urine. Treatment consists of sulfhydryl compounds that form more soluble compounds with cystine through sulfhydryl exchange as well as alkalinization of urine and hydration to make cystine more soluble.