Pharmacokinetic aspects of antidepressant treatment in the elderly

1. Physiological and metabolic changes with ageing may affect the pharmacokinetics of antidepressant drugs. 2. Pharmacokinetic parameters following single doses of antidepressants in the elderly tend to be altered compared with younger subjects. 3. Elimination half-life tends to be prolonged for most antidepressant drugs in the elderly due to decreased clearance and increased volume of distribution. 4. Steady-state plasma concentrations tend to be increased in elderly patients. 5. Inter-individual differences usually account for the majority of the variance in kinetic parameters rather than an effect of ageing per se. 6. The increased propensity for side effects in the elderly is probably due to pharmacodynamic rather than pharmacokinetic alterations with age.