Pharmacokinetics of Interferons

Abstract

Interferons are able to induce resistance to viruses, and are apparently able to induce a number of potentially useful modifications of immune mechanisms. So, we now begin to administer it to patients to achieve the effects desired. But how much do we need to administer to attain and maintain effective levels? In fact, what is the desired level? And how long must it be maintained? We have previously seen (Fig. 8) that even very high levels of circulating interferons induced in animals very rapidly disappeared within just a few hours. Where did this interferon go? And what happened to it? The answers to these questions are not yet known. Present applications of interferons are based on the limited information presented in this Section: interferon is usually administered on the basis of giving as much as possible, based on either availability or restrictions imposed by “side” effects (which have usually been presumed to be due to non-interferon impurities in the preparations). Much more work is required on the pharmacokinetics of interferons before clinical applications will be more rational. In view of some of the differences observed with high or low doses mentioned previously in cell cultures and some that will be mentioned later (Section XIII) it seems likely that more attention should be paid to this problem.