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.