Society already achieves economic benefits from generic substitution but fails to do the same for therapeutic substitution.
OBJECTIVE
To assess the potential annual savings due to generic and therapeutic substitution of statin therapy for the general Dutch population, taking the patients medical history into account.


METHODS
We conducted a population-based costing study using the PHARMO Record Linkage System (RLS). PHARMO RLS contains drug dispensing records from a representative sample of pharmacies located in more than 50 regions in the Netherlands. We selected all statin users in the database since 2003. The cost-savings of generic substitution of statin therapy for all simvastatin and pravastatin users, and of therapeutic substitution of statin therapy for other statin users were calculated. Substituting current users and new users of statins were considered separately. Therapeutic substitution was based on the medical history of the individual patient. Patients were only substituted if there was an appropriate substitute available. The appropriateness of substitution was based on drug-drug interactions between statins and possible comedication and the availability of an equipotent alternative.


RESULTS
Substituting (generic and therapeutic) statin therapy for all current users would lead to potential annual savings of approximately 87 million euros. Substituting (generic and therapeutic) all starters on statin therapy would lead to potential annual savings of around 51 million euros. In the case of generic substitution only, the potential annual savings for all current simvastatin and pravastatin users would be 2.4 million euros and for the new users about 1.8 million euros.


CONCLUSIONS
From an economic point of view, society could gain a lot from substituting statin therapy, especially from therapeutic substitution.
Gumbs
Pearl D
PD
Division of Pharmacoepidemiology and Pharmacotherapy, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, Utrecht, The Netherlands.
Verschuren
W M Monique
WM
Souverein
Patrick C
PC
Mantel-Teeuwisse
Aukje K
AK
de Wit
G Ardine
GA
de Boer
Anthonius
A
Klungel
Olaf H
OH
D017046:Cost Savings / Q000706:statistics & numerical data; D016527:Drug Costs / Q000706:statistics & numerical data; D016568:Drugs, Generic / Q000191:economics / Q000627:therapeutic use*; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D009426:Netherlands; D010349:Patient Compliance; D010593:Pharmaceutical Services / Q000191:economics / Q000706:statistics & numerical data; D013810:Therapeutic Equivalency
D016568:Drugs, Generic; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors