Comparative risks of venous thromboembolism among users of oral contraceptives containing drospirenone and levonorgestrel.

Commentary Background Two case-control studies, both with the involvement of the Boston Collaborative Drug Surveillance Program, have recently been published in the British Medical Journal (Jick et al. 1 and Parkin et al. 2) in which increased risks of venous throm-boembolism (VTE) among users of drospirenone (DRSP)-containing oral contraceptives (OCs) compared with lev-onorgestrel (LNG)-containing OCs were reported. Both studies used electronic medical databases [USA: managed care plans (Pharmetrics)