Polymorphism of mu-opioid receptor gene (OPRM1:c.118A>G) does not protect against opioid-induced respiratory depression despite reduced analgesic response. - Romberg RR; Olofsen E; Bijl H; Taschner PE; Teppema LJ; Sarton EY; van Kleef JW; Dahan A (Anesthesiology, 2005)