Impact of '4+7' volume-based drug procurement on the use of policy-related original and generic drugs: a natural experimental study in China.

'4+7' policy is conducive to generic substitution, drug price reduction and pharmaceutical cost-containment in China. The overall quality level of drug use of the Chinese population increased after policy intervention, especially in primary healthcare settings. However, the increased DDDc of non-winning generic drugs and alternative drugs should draw the importance of further policy monitoring.