WORLD MARKETS FOR CNS AND GASTROINTESTINALS

Eli Lilly's antidepressant Prozac (fluoxetine) is the first billion-dollar central nervous system drug treatment, according to a new study from Datamonitor. Prozac, the first of the selective serotonin reuptake inhibitors which are revolutionizing the market, is significantly ahead of other leading antidepressants, with 9% of the market. Another top-selling SSRI is Pfizer's Zoloft (sertraline), in 13th place with 1992 sales of $195 million and which accounts for a 2% share of the market.

The second leading drug in this market is Upjohn's anxiolytic Xanax (alprazolam), with 1992 sales of $652 million and a 5% share. Next is Ciba's nicotine patch product Nicotinell, with sales in 1992 of $440 million and 4% of the market. Datamonitor says a portion of these sales are now OTC, since the product has switched from prescription-only status in some countries. 1992 may prove to have been a peak year for nicotine patches, since the market has a strong "fad element," and if other world markets follow the US pattern, they will contract considerably this year.

Datamonitor predicts that the top-selling drugs in this market will change considerably over the next ten years. Newly-launched SSRIs will join Prozac at the top of the market, taking share from the older tricyclic antidepressants. Alzheimer's disease treatments are likely to move up later in the 1990s; the first, Warner-Lambert's Cognex (tacrine), is already on the market. These products have yet to prove their efficacy, but if accepted they have an immense potential market.