Prozac is a brand-name medicine doctors give for depression (a long, heavy sadness that will not lift) and for some kinds of anxiety (feeling very worried, often for no clear reason). The drug inside the brand is fluoxetine. It does not work like a sweet that makes you happy in an hour; people usually take it every day, and the change in mood, if it comes, comes over weeks. Doctors and patients both use the word, and in ordinary talk people sometimes stretch it to mean “any pill for feeling down,” though that is loose — Prozac is one famous brand, not the name of every such medicine. It can help many people feel more like themselves again; it can also bring side effects, such as trouble sleeping, a dry mouth, or less interest in sex, and a few people feel worse before they feel better, which is why it is meant to be used with a doctor, not borrowed from a friend. Some doctors do worry, as the tidy line says, that a pill can become a stand-in for talking about life — though actually, for quite a few people, the pill is what makes talking and daily life possible at all. The name still sounds famous, even a little old-fashioned now that other brands sit beside it.