MANY PROBLEMS RELATING SPECIFICALLY TO THE PROCESSES OF AGING AFFECT THE USE OF MEDICATION, E.G., AN OLDER PERSON MAY NOT ABSORB A MEDICATION INTO THE BLOODSTREAM AS WELL AS A YOUNGER PERSON. A COMPOUNDING PROBLEM IS THAT MANY ELDERLY PERSONS HAVE SEVERAL ILLNESSES AT THE SAME TIME, EACH REQUIRING A COMBINATION OF TWO OR THREE DRUGS. ADVERSE DRUG REACTIONS AMONG OLDER PERSONS ARE VERY COMMON. CLOSELY RELATED TO THE PROBLEMS OF ADVERSE REACTION AND MULTIPLE DRUG USAGE IS THE PROBLEM OF IMPROPER COMPLIANCE WITH THE PHYSICIAN'S ORDERS. IMPAIRMENT OF SIGHT, HEARING, OR COMPREHENSION CAN MAKE IT DIFFICULT FOR THE ELDERLY PATIENT TO UNDERSTAND PRESCRIPTION INSTRUCTIONS. AN IMPORTANT STEP IN IMPROVING THE MEDICATION HABITS OF ELDERLY PERSONS IS PATIENT EDUCATION BY PHYSICIANS AND PHARMACISTS. PHARMACISTS MUST ALSO RECOGNIZE THE INTRICACIES OF GENERIC DRUG SUBSTITUTION, TAKING INTO CONSIDERATION FACTORS OF COST, AVAILABILITY, THERAPEUTIC EQUIVALENCE, AND SAFETY. PROBLEMS IN THE DISTRIBUTION OF MEDICATION IN NURSING HOMES, INCLUDING COSTLY WASTAGE AND THE POSSIBILITY THAT UNUSED MEDICATION MAY FIND ITS WAY INTO THE ILLICIT DRUG MARKET, ARE BEING ADDRESSED THROUGH THE UNIT DOSE SYSTEM.