Co‐medication of statins and CYP3A4 inhibitors before and after introduction of new reimbursement policy

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

AIMS

To assess the prevalence of co‐medication of statins and CYP3A4 inhibitors before and after introduction of a new Norwegian reimbursement policy, which states that all patients should be prescribed simvastatin as first‐line lipid‐lowering therapy.

METHODS

Data from patients receiving simvastatin, lovastatin, pravastatin, fluvastatin or atorvastatin in 2004 and 2006, including co‐medication of potent CYP3A4 inhibitors, were retrieved from the Norwegian Prescription Database covering the total population of Norway. Key measurements were prevalence of continuous statin use (two or more prescriptions on one statin) and proportions of different statin types among all patients and those co‐medicated with CYP3A4 inhibitors.

RESULTS

In 2004, 5.9% (n= 272 342) of the Norwegian population received two or more prescriptions on one statin compared with 7.0% (n= 324 267) in 2006. The relative number of simvastatin users increased from 39.7% (n= 112 122) in 2004 to 63.1% (n= 226 672) in 2006. A parallel increase was observed within the subpopulation co‐medicated with statins and CYP3A4 inhibitors, i.e. from 42.9% (n= 7706) in 2004 to 63.6% (n= 13 367) in 2006. For all other statins the number of overall users decreased to a similar extent to those co‐medicated with CYP3A4 inhibitors.

CONCLUSIONS

In both 2004 and 2006, the choice of statin type did not depend on whether the patient used a CYP3A4 inhibitor or not. Considering the pronounced interaction potential of simvastatin with CYP3A4 inhibitors, a negative influence of the new policy on overall statin safety seems likely.

DOI: 10.1111/j.1365-2125.2008.03345.x

View this article

• Full article (html)
• Enhanced article (html)
• PDF
• References