Risk:benefit assessment of old medicines.

Any meaningful discussion about the present value of old drugs requires appropriate comparisons with new drugs. While there is noisy propaganda claiming the superiority of new drugs, the evidence supporting these claims is often scanty and poor. Therefore, the database utilizable to evaluate old and new drugs is incomplete and fragile. There are several reasons, including the poor dossiers presented for the approval of new drugs, the lack of comparisons aimed at showing superiority of new drugs, the bias frequently involved in clinical trials and the conflict of interests. This brief discussion reviews these questions and gives some examples by comparing diuretics and new antihypertensive agents, ticlopidine and clopidogrel, and atypical and classical antipsychotic agents.