Objective: Animal studies suggest that gold compounds impair haem synthesis and increase haem degradation and, as a result, reduce activity of the hepatic haemoproteins cytochromes P-450. The aim of this study was to investigate whether intramuscular gold exerts similar effects in patients with rheumatoid arthritis (RA).
Methods: Urinary porphyrin and precursor excretion, erythrocyte protoporphyrin, and antipyrine clearance, were measured in 6 patients with RA before and 10 weeks after commencement of intramuscular gold.
Results: Parameters of haem metabolism were unaffected by gold. While antipyrine clearance was not statistically changed after gold treatment, in 3 of the patients there was an average decrease in antipyrine clearance of 23%.
Conclusion: Further studies examining RA patients at different time points are required to investigate further the possibility of reduced hepatic drug metabolising activity during prolonged treatment with gold.