OBJECTIVES: To explore the trends in physicians' prescribing of promotional targeted drugs (PTD) in two categories - Statins and COX-2 inhibitors, before and after implementing the pharmaceutical policies which included the National Essential Drug List (NEDL), the health benefit schemes, and the regulation of the hospital Pharmacy & Therapeutic Committee (PTC). METHODS: Electronic outpatient prescription records of the PTDs and the established drugs in the same category at a teaching hospital were compared. Data on how and when the PTD got approved by the PTC including the prescribing restrictions were also assembled. A time series analysis of prescription data for each drug was constructed and marked for any known phenomena during 1998-2004. RESULTS: The highly promoted drugs in both groups showed significant increases in drug uses after the implementation of pharmaceutical policies especially if the drug was listed in the NEDL. The majority of the drug costs were acquired by cash payment and the price for expensive drugs varied between 5-10 times that of the alternatives in the same category. While the sales shares for expensive drugs increased enormously, the trend decreased drastically for the alternative drugs. Among the health schemes, the Civil Servants Medical Benefit Scheme beneficiaries were likely get expensive drugs than others. CONCLUSIONS: This exploratory study reveals the different types of pharmaceutical policies that can have an impact on the trend of physicians' PTD prescribing. The findings call for further in-depth investigation of critical factors influencing physician prescribing behavior of PTDs in order to curb the escalating drug cost and promote rational drug use in the country.