In Estonia, HMG-CoA reductase inhibitors are widely used to modify lipid levels but there are no current data on additional medicines prescribed alongside the statins. The aim of this study was to identify the frequency of potential clinically relevant interactions at a national level among an outpatient population treated with statins between January and June 2008, based on the prescription database of the Estonian Health Insurance Fund. This retrospective prevalence study included 203,646 outpatients aged 50 years or older, of whom 29,367 received statin therapy. The study analysed individuals who had used at least one prescription medicine for a minimum of 7 days concomitantly with statins. Potential drug interactions were analysed using Epocrates online, Stockley’s Drug Interactions, and the drug interaction database developed in Estonia. Statins metabolised by the CYP3A4 isoenzyme were prescribed to 64% of all statin users. Medicines known to have potentially clinically significant interactions with statins were prescribed to 4.6% of patients.
The drugs prescribed concomitantly most often with simvastatin were warfarin (5.7%) and amiodarone (3.9%), whereas digoxin (1.2%) and ethinylestradiol (2%) were prescribed with atorvastatin.
Potential interactions were not detected in the treatment regimens of rosuvastatin, pravastatin, and fluvastatin users.
 Cholesterol Treatment Trialists’ (CTT) Collaboration, Baigent C.,
BlackwellL., Emberson J., Holland L.E., Reith C., Bhala N., Peto
R., Barnes E.H., Keech A., Simes J., Collins R., et al., Efficacy
and safety of more intensive lowering of LDL cholesterol:
a meta-analysis of data from 170,000 participants in 26
randomised trials. Lancet, 2010 , 376(9753), 1670-1681
 Wenger N., Lewis S.J., et al., Use of statin therapy to reduce
cardiovascular risk in older patients. Curr. Gerontol. Geriatr.
Res., 2010, 915296
 Kapur N.K., Musunuru K., et al., Clinical efficacy and safety
of statins in managing cardiovascular risk. Vasc. Health Risk
Manag., 2008, 4(2), 341-353
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