An unpublished 2-year randomized study (ENHANCE) on the effect of adding ezetimibe 10 mg to simvastatin 80 mg in 720 patients with heterozygous familial hypercholesterolemia has been in the news recently. About 80% of these patients had previously been treated with statins. The primary endpoint was the change in the intima-media thickness (IMT) of the carotid artery (baseline 0.68 and 0.69 mm); the IMT increased by 0.0111 mm with ezetimibe plus simvastatin and 0.0058 mm with simvastatin 80 mg alone (p=0.29). The ezetimibe- simvastatin combination lowered LDL-C by 58% compared to 41% lowering with simvastatin alone (p<0.01). The study was not powered to assess cardiovascular events; cardiovascular deaths occurred in 2 patients treated with both drugs and 1 on simvastatin alone.

Ezetimibe, an inhibitor of cholesterol absorption, is available both alone (Zetia) and in combination with 10, 20, 40 and 80 mg of simvastatin (Vytorin). No data have been published on the effect of ezetimibe on cardiovascular events with or without simvastatin. Whether addition of ezetimibe to a statin is as effective as raising the dose of the statin in decreasing the number of cardiovascular events remains to be determined in larger studies that are underway.

Neither Zetia or Vytorin is recommended for initial treatment of hypercholesterolemia.