Homocysteine elevation with fibrates: is it a class effect?

Background: Case-control and prospective studies indicate that an elevated plasma homocysteine level is a powerful risk factor for atherosclerotic vascular diseases. Certain medications can induce hyperhomocystinemia, such as methotrexate, trimethoprim and anti-epileptic drugs. There are few reports indicating an interaction between lipid-lowering drugs (cholestyramine and niacin) and homocysteine. Recently, an interaction was shown between fenofibrate and benzafibrates (a fibric acid derivative) and homocysteine plasma levels.

Objectives: To evaluate the effects of different fibrates on plasma homocysteine levels and to measure the reversibility of this effect.

Methods And Results: We investigated the effects of ciprofibrate and bezafibrate on homocysteine levels in patients with type IV hyperlipidemia and/or low high density lipoprotein levels. While a 57% increase in homocysteine was detected in the ciprofibrate-treated group (n = 26), a 17% reduction in homocysteine was detected in the group treated with bezafibrate (n = 12). The increase in homocysteine in the ciprofibrate-treated group was sustained for the 12 weeks of treatment and was partially reversible after 6 weeks of discontinuing the ciprofibrate therapy.

Conclusions: These results indicate that an increase in plasma homocysteine levels following administration of fibrates is not a class effect, at least in its magnitude. Moreover, it is reversible upon discontinuation of the treatment.