Failure of orally administered hydroxychloroquine sulphate to prevent venous thromboembolism following elective hip operations.

In a double-blind, randomized trial of orally administered hydroxychloroquine sulphate in the prevention of venous thromboembolism after elective surgery on the hip, the drug or a placebo was given to fifty consecutive patients. Therapy was commenced on the day before the operation and continued for fourteen days. The diagnosis of deep venous thrombosis was made by daily thermographic scanning of the legs and confirmed by phlebography. The diagnosis of pulmonary embolism was made by perfusion lung scanning. No significant difference in the incidence of thromboembolism was found between treated and control groups. The results provide evidence that substances which reduce the incidence of thromboembolism in general surgery may not be effective in operations on the hip.