Antidepressant medications are taken daily or more frequently based on both tradition and pharmacokinetics of the drugs. However, weekly administration may be a feasible option for drugs with a long elimination half-life and flat dose-response curve. In addition to providing effective control of symptoms, it is possible that weekly administration could also benefit patients by reducing costs and minimising drug interactions and adverse effects. The selective serotonin (5-hydroxytryptamine; 5-HT) reuptake inhibitor fluoxetine appears to be a candidate for once weekly administration.