Antidepressant utilization in primary care in a Spanish region: impact of generic and reference-based pricing policy...

To describe the evolution of antidepressant use in primary care in the Valencian region (Spain) from 2000 to 2004 and to analyze the effects of reference-based price and generic drugs introduction on drug utilization and cost saving.

Retrospective observational study in primary care using sales data collected from antidepressant group (N06A), corresponding to the period 2000-2004. Defined daily dose (DDD)/1000 inhabitants per day were obtained as consumption data. Cost and cost/DDD rate evolution was related to reference price system implantation.

Antidepressant utilization progressively increased by 44.0% from 30.3 DDDs/1000 per day in 2000 to 43.5% in 2004. Selective serotonin reuptake inhibitors (SSRIs) comprised 77% of the total consumption where paroxetine, sertraline and fluoxetine were the most used drugs in 2004. The proportion of relative use and cost of fluoxetine declined after a reference price and the introduction of generic competitors were put into effect in 1999; cost/DDD was reduced by 1.8. Third-generation antidepressants showed a fast rising rate i.e. venlafaxine utilization multiplied by 2.2; this drug with the higher cost/DDD was not subjected to the reference price system. Reduction in citalopram utilization was related to a replacement by its recently marketed enantiomer escitalopram.

In 2004, reference price policy and the implementation of generic drugs reduced the antidepressant cost by DDD. However, antidepressant expenditure increased since 2000 due to a continued growth in consumption (SSRIs and novel agents) and a displacement of prescriptions to drugs that were not included in the reference price policy.