Mary, I cannot locate Brian's question, but I came full face with half life of Valium when my dad with PD was overdosed by a cardiologist and anesthesiologist when he had a pacemaker replaced. Valium has an extremely long half-life and indeed he was in a coma for two months after several large IV doses given. His neurologist did not expect a good prognosis, but he did eventually recover. I think that the half-life does relate to the length of effect of the drug. Aloha, Gail -- Gail B. Post, RN,MS,CSN Maryknoll Schools Honolulu, HI 96822