To the Editor.
—In the excellent article, "Leukopenia due to Penicillin and Cephalosporin Homologues," by Homayouni et al in the Archives (1979; 139:827-828), the authors appropriately caution against slavishly adhering to recommendations in many standard textbooks concerning the administration of specific daily quantities of antibiotics without taking into consideration the weights of the patients requiring these drugs.The authors stated, "It has been conventional to administer antibiotics to children on a milligram per kilogram per day plan. This practice should be extended to adults as well." An important caveat is in order should this recommendation be construed to apply to antibiotics in general (including those in which renal excretion plays an important role) and their use among all segments of the adult population. Just as children are not "miniature adults," adult subjects are certainly far from being homogeneous in their response to drugs. With aging, for example, there are notable