The management of psychotropic drugs is a daily preoccupation for geriatric psychiatrists and geriatricians alike. The lack of controlled clinical trials in very old patients (over 80 years old) often leads to empirical therapy. The multiple somatic co-morbidities of old patients, the high prevalence of potential drug-drug interactions and a wish to implement an increasingly patient centered approach all influence psychotropic drug prescription which tends to be simplified and individualized. This review is an attempt to depict the general principles and precautions we, as in-hospital geriatricians, geriatric clinical pharmacologists and geriatric psychiatrists in Geneva, Switzerland, have found helpful after many years of interaction with elderly patients and their families, and shared responsibility for the care of these very frail patients.