The influence of Rx-to-OTC changes on drug sales. Experiences from Sweden 1980-1994

A descriptive study of national sales data from Sweden to find out the effect of over-the-counter (OTC) switches on total sales of a number of drugs. During the period 1980-94, 16 drugs were changed from prescription only (Rx) status to the Swedish OTC market. Total sales increased for 14 out of these 16 drugs. The increase was seen soon after the change to OTC status. Two years after the change an average increase of 36% was seen. In the following 2 years, the increase was typically very modest (average 1%). Large differences in the changes were seen for the individual drugs. The prescription of OTC packs decreased on average by 26% during the first 2 years after the switch. Converting this decrease in sales in terms of number of packs no longer prescribed led to an estimated yearly saving of SEK 200 million ($US 30 million) for the national drug budget. Taking account of the total increase in defined daily doses (DDDs) 2 years after the change for those 16 drugs led to an estimated yearly saving of SEK 2.5 billion ($US 400 million).