“Half-life” is the amount of time for the concentration of drug in the blood to fall by 50 percent. This time-period will vary between individuals. Commonly used “short” half-life benzodiazepines include Ativan and Xanax, while “long” half-life benzodiazepines include Klonopin, Valium, and Librium. Of note, Valium and Librium are further transformed into “active” metabolites, each with their own elimination half-lives. This means that they accumulate gradually and are cleared more slowly from the body, which can provide an advantage in tapering, as it can help prevent withdrawal between doses. Elimination half-lives are often doubled or tripled in the elderly, due to less efficient metabolism in the liver.