Evaluation of Drug Dosage and Prescription in the Aged

Abstract

Recently, along with an increase in aged patients, the frequency of drug administration has increased. It is said that drug hazards of treatment result in side effects; however, I would like to study the problematical points of why there are many side effects among the aged. First, studies in the determination of drug doses, discovery of pharmacological effects. and establishing drug standards were made using young, healthy animals and humans. Furthermore, this dose is applied to aged people as is. Secondly, dosage is calculated by drug concentration in the blood.
However, in calculating this, the distribution volume is calculated from percentage of weight of the lean body mass without taking into consideration the constituent fat in the composition of the body; in the case of the aged with obesity, and those using liposoluble drugs, it does not mean that drug concentration in the blood will reflect the effective amount. Therefore, as the third point, it is considered that side effects will not occur if the drug dose is given within the permissible limits for the organ function. If the changes due to aging which have to do with absorption metabolism and excretion of the drug dose are measured and compared with that of young and prime ages, and the common factor of each organ function is calculated, that will be the safety minimum. As a result of my studies on the change of organ function in aging, it became clear that aged liver function is 1/2 to 1/2.4, kidney excretion function is 1/2 to 1/3, digestive function drops, and immune function is 1/2. Therefore, from the standpoint of organ function, it is appropriate to start with 1/2 to 1/3 dose, gradually increasing this to seek the optimum amount. The fourth problem is that side effects occur due to combined dosage, even though each dose is not excessive in itself. This is due to drug interaction. Therefore, since side effects occur due to delay in absorption, abnormality of pH of the stomach, stagnation of contents of the stomach, conflict of protein in the process of distribution, substitution phenomena, enzyme induction, changes in the effects of drugs due to inhibition, abnormality in the order of the function of excretion, and inhibitors of metabolism, the combined use of drugs which cause interaction should be avoided. The fifth point is that to gain the benefits of drugs, the right dose must be taken; however, the aged lack in correctly taking drugs because of misunderstanding, and have troubles with eyesight and hearing ability due to senility. Therefore, the lack of education of the elderly in taking drugs can be raised as an additional problem. Solving these points will greatly reduce side effects in drug treatment of the aged.