Chrysotherapy: pharmacological and clinical correlates.

Relationships between gold administration and serum gold content were observed in 56 RA subjects receiving up to five years of weekly chrysotherapy. Wide fluctuations in serum gold responses to standard 50 mg IM injections were noted. Individual adjustments to dosage schedules were made as dictated by patient serum gold responses. Enhanced clinical and laboratory response was prolonged with higher sustained serum gold concentration greater than 300 mug per cent. Maintaining serum levels greater than 300 mug per cent is postulated to facilitate access of gold to "effector sites" within the deeper compartments by providing higher sustained gradients between superficial (blood) and deeper body compartments. The complexity of the system of effector sites responsive to gold and their divergent location within the body likely affects the accessibility of the agent for these sites; hence, affecting the correlation between gold levels and therapeutic response. The application of pharmacokinetic principles in chrysotherapy, nevertheless, provides the basis for optimizing accessibility of the agent and the therapeutic response. (J Rheumatol 2: 401-410, 1975).