Effect of a non-steroidal anti-inflammatory drug, diclofenac, on haemostasis in patients undergoing total hip replacement.

ABSTRACT

Haemostasis was studied in patients receiving diclofenac for postoperative pain relief. Intravenous diclofenac 75 mg over 60 min, followed first by an infusion of 5 mg/h for 15 h and then by 50 mg every 8 h orally was administered to 20 patients undergoing total hip replacement. Eighteen patients receiving a placebo infusion and dextropropoxyfen per os served as controls. The results showed no statistically significant differences between the groups in blood loss, bleeding time (IVY), partial activated thromboplastin time and prothrombin complex assay or in platelet count. The measurements were performed preoperatively, 3 h postoperatively and on the fourth and tenth postoperative days. Plasma concentrations were also determined in ten patients undergoing knee arthroscopy. An i.v. diclofenac infusion of 75 mg over a period of 15 min was administered either once (to half of the patients) or twice. The mean diclofenac concentrations were 28 +/- 5 nmol/ml (+/- s.d.) after 15 min and 36 +/- 12 nmol/ml after the second infusion. The bleeding time in the arthroscopy patients receiving one or two bolus infusions of 75 mg diclofenac remained at the control level. It is concluded that diclofenac given as an intravenous infusion of 75 mg in 60 min, then 5 mg/h for 15 h, followed by 50 mg every 8 h orally, is a safe as dextropropoxyfen for pain relief in patients undergoing major orthopaedic surgery as far as coagulation data are concerned.