MODELING THE MARKET UPTAKE OF NEW DRUGS FOLLOWING LISTING FOR SUBSIDY IN AUSTRALIA - A REPORT FROM THE DRUG-UTILIZATION-SUBCOMMITTEE OF THE AUSTRALIAN-PHARMACEUTICAL-BENEFITS-ADVISORY-COMMITTEE

The market uptake of five drugs following subsidy listing in Australia during the period 1990 to 1992 has been modelled using the sigmoid E(max) model for drug-receptor binding. Utilisation trends for simvastatin, omeprazole, budesonide, fluoxetine and moclobemide in defined daily dose (DDD) per 1000 population per day were smoothed by expressing as rolling annual averages. The results indicate good fits of the model to the data except for omeprazole, with good estimates of uptake rate and eventual maximum utilisation. Substantial differences between the drugs occurred in uptake rate which may be related to public education campaigns on asthma and coronary heart disease occurring during the release period. The very slow uptake of omeprazole relative to other drugs is likely to be due to restrictions on subsidised use. Modelling the market uptake rate and eventual utilisation of new drugs is useful as an aid to regulatory, quality use of medicines and financial decisions and allows comparisons between drugs to investigate factors important in market uptake.