Once-daily dosing of enoxaparin (a low molecular weight heparin) in prevention of deep vein thrombosis after total hip replacement.

The main results of three successive prospective clinical trials which represent the successive steps in the definition of once-daily dosing of enoxaparin in elective hip surgery are demonstrated. In the first trial, a dose of 40 mg/day (4000 anti-Factor Xa IU), in one or two subcutaneous injections, was preferred to a dose of 60 mg because it gave the same efficacy with a better tolerance. In a second, randomized double-blind trial, the two modes of administration of a dose of 40 mg, in one or two injections daily, were found to be equivalent with regard to tolerance and efficacy. In a third prospective, controlled, randomized, double-blind multicentre trial, once-daily dosing of enoxaparin at the dose of 40 mg was found superior to 5000 IU of unfractionated heparin tds with regard to tolerance and efficacy. It is concluded that the dose of 40 mg/day, begun 12 h pre-operatively, gives the best benefit:risk ratio in elective hip surgery.