Decreasing Number of Medication Prescriptions After e-Prescriptions Became Mandatory and Their Valid Period Was Extended: A Big Bang Policy Change in Finland in 2017.

We measured the first time the number of prescriptions in Finland by using a centralized national shared repository of e-prescriptions and their dispensing data. This was made possible by introducing two policy interventions that were effective since 1 January 2017: mandatory e-prescribing and extension of a prescription's valid period from 12 months to two years. The trend in recording e-prescriptions started decreasing since the 'big bang', but pharmacy dispensations were not affected, as followed up to September 2019. It is possible to monitor the effects of health policy interventions by utilizing national e-health data systems, especially at the occurrence of a natural experiment.