smart drug
n. A drug that improves a person's cognitive abilities.
Examples
2003
The new class of cancer drugs, often called "smart" drugs, target this genetic cascade, jamming it up at various points in the process. These drugs draw from recent insights into the genetics of cancer cells, killing cancer cells only, unlike older treatments which often destroyed cells indescriminately, causing miserable side effects and offering limited benefit. At the moment, only a handful of smart drugs are in widespread use, though that may change soon.
—Raja Mishra, “Advances begin to tame cancer,” The Boston Globe, July 06, 2003
2003
Back in the 1930s, Aldous Huxley's prescient Brave New World offered a universal panacea, a drug called Soma, which removed all existential pain. Today's brave new world will have a multitude of designer psychotropics, available either by consumer choice (so called smart drugs to enhance cognition) or by state prescription (Ritalin for behaviour control). These are the emerging neurotechnologies, crude at present but becoming steadily more refined.
—Steven Rose, “Brave new brain,” The Guardian (London), May 08, 2003
1991 (earliest)
The latest type of drug to slip through the FDA's legal loophole — in rapidly increasing numbers — is "smart pills": memory and intelligence boosters.

There are plenty to choose from. Many drugs commonly prescribed for depression, heart disease and arthritis — even birth-control — are rumoured to have the beneficial side-effect of improving mental ability. The loophole in the FDA's rules lets Americans buy these drugs without having been prescribed them for their intended uses. Recently a new publishing company called B&J, from Santa Cruz in California, issued a buyer's guide to some 60 smart drugs and nutrients. It was compiled by Ward Dean, an expert on ageing who runs a medical practice in Pensacola, Florida, and John Morgenthaler, a journalist. They scoured medical literature to find all the drugs that have some claim, from animal or human studies, to enhance memory or intelligence.
—“Don't go gaga, be like Babar,” The Economist, February 02, 1991
Notes
The new class of cancer drugs, often called "smart" drugs, target this genetic cascade, jamming it up at various points in the process. These drugs draw from recent insights into the genetics of cancer cells, killing cancer cells only, unlike older treatments which often destroyed cells indescriminately, causing miserable side effects and offering limited benefit. At the moment, only a handful of smart drugs are in widespread use, though that may change soon.

At the end of last year, there were 100 new cancer drugs in the final phase of human testing, according to NCI statistics, most of them smart drugs. Some directly disrupt tumor cells' replication machinery. Others block growth signals from reaching the cells. One class of drugs cut off tumors' blood supply, starving them to death.
—Raja Mishra, “Advances begin to tame cancer,” The Boston Globe, July 06, 2003