polypharmacy
n. the simultaneous use of a variety of drugs of the same or different classes with the intent of producing a more robust therapeutic response. Polypharmacy for mental disorders may, for example, involve the administration of two or more antidepressants in the hope that agents with different mechanisms of action will produce greater clinical improvement than that seen with any one drug alone. Polypharmacy is often criticized because of the lack of well-controlled studies supporting its use and the greater likelihood of adverse drug interactions when two or more drugs are used simultaneously. However, for those individuals unsuccessfully treated with several trials of monotherapy, or for whom monotherapy achieves suboptimal results, polypharmacy may be therapeutically indicated and appropriately managed.