In older animals, the processes of absorption, distribution, metabolis
ation, and elimination of drugs differ from the conditions observed in
younger animals and partly show a considerable interindividual variab
ility. The article gives an overview and also some examples of physiol
ogical conditions on which age-related peculiarities are based. The fa
ct that only little knowledge is available, and the interrelationships
between physiologic and pathophysiologic prophysiologic and pathophys
iologic processes make it difficult to estimate pharmacokinetic partic
ulars in the individual aged patient. General dosage recommendations c
an therefore not be given. When treating aged patients, the veterinari
an should especially consider a possibly reduced elimination for a pos
sible drug treatment schedule.