Abstract
Bucillamine (Bu) is a new anti-rheumatic agent synthesized in Japan. Use of this agent has been prohibited in patients with impaired renal funtion, because it is eliminated via the kidneys. This paper reports the favorable effect of Bu in a hemodialysis patient with amyloidosis secondary to rheumatoid arthritis (RA), and an investigation of the pharmacokinetics of this agent.
A 56-year-old woman with RA since 1967 developed renal failure in 1984. A diagnosis of secondary amyloidosis was made on the basis of a lip biopsy. Hemodialysis therapy was begun in 1985. At the start of hemodialysis therapy, the patient's RA was classified as stage IV, class III. In 1992, when her arthralgia became uncontrollable with steroid hormones and analgesic agents, and her quality of life deteriorated, she was treated with Bu.
First, we investigated the pharmacokinetics of this agent. On non-dialysis days, the serum half-life of Bu was almost the same as in a subject with normal renal function, but the serum half-life of its two active metabolites, SA-981 and SA-679, was considerably prolonged (9.3 hours and 24.4 hours, respectively). On dialysis days, Bu and its active metabolites could be removed by hemodialysis. Based on the results of the phrmacokinetic study, the dosage was set at 100mg after each hemodialysis session.
Four weeks after the start of Bu, the patient's arthralgia, objective findings and Lansbury index had markedly improved. Improvement of her arthralgia enabled the patient to climb stairs, and her quality of life also improved. There were no signs of accumulation of Bu or its metabolites in the blood.
Although this is only a single case report, the results suggest that Bu is useful in patients with RA accompanied by renal dysfunction by decreasing the dosage of Bu according to the results of the pharmacokinetic investigation.
