[Pharmacology of pain in older persons]

Pain prevalence is high in older persons. Aging is associated with modification in pain perception and with noticeable changes in the pharmacology of analgesics. Therefore, after an accurate identification of the presence and type of pain, treatment must take into account various factors including comorbidities and polymedication that are landmarks of aging. Among pharmacokinetic changes with age, one must especially focus on renal elimination of analgesics and their metabolites, and on the increased risk of drug interactions and side-effects. Pharmacodynamic changes with age stress the vulnerability of elderly persons to drugs and require a lower dosage and a slower titration. Analgesics, co-analgesics and their contra-indications do not differ from those in younger patients, and their side-effects, well documented, can often be anticipated. It is therefore necessary when treating pain in the elderly to have a double systematic reflex of pain identification and of drug interactions, in order to improve pain treatment and quality of life, and to optimize the analgesic benefit/risk ratio.